Help with choice of Heating/ Cooling equipment for Southern New England

Discussion in 'HVAC Heating & Cooling' started by Scup, Jan 11, 2014.

  1. Scup

    Scup New Member

    Messages:
    43
    Location:
    Stonington, CT
    Being a newbie to this site, I quickly became overwhelmed with the core knowledge of this form, and how quickly members are willing to offer their experienced advice on various subjects. No question about it, I would be a fool not take advantage of this free but very valuable service.

    I am 75 years old and know I am going to have to redo my entire heating/cooling system since it is well past its useful service life. What I wish to know from members what should I consider as a replacement for use in southern New England.

    This is what I currently have: A 37 year old Williamson Five in one hot air oil fired Furnace, air conditioner, humidifier, electrostatic filter, and dehumidifier. I quickly disconnected the humidifier 37 years ago since it continuously fed a trickle of water over a grid in the duck work. Perfectly happy with a standalone humidifier for winter use! The electrostatic filter failed ten years ago, but left a gap large enough that regular throw away filters inserts have worked out fairly well. The burner, air conditioner, and dehumidifier all still work although after a few mice ate up some of my wiring and a few electrical components failed, I had to rewired it up as a single high speed air conditioner. It probably was one of the first two speed air conditioners out there.

    The oil burner is so obsolete I do not wish to talk about it, and the air conditioner, while it still cools the whole house down quickly, it is on its last legs.

    Next to the Williamson furnace is an independent wood fired Bison furnace tied into the duck work. While it was designed as an auxiliary add on, it has become my primary heating unit and is still very functional.

    All of this is in a very cramped area with no room for an oil tank. Having an outdoor oil tank in Connecticut is a major liability; hence, after periodically replacing oil tanks as not to push my luck, I decided to give up on oil. Cost is a major factor and oil is not the bargain it was in the seventies.

    Now here is the $64,000.00 question: what would you replace my heating/cooling systems with?

    Natural gas is not available. I am sort of in love with my wood furnace and plan on retaining it, and if necessary replace it the future. A new air conditioning system is needed and I am thinking about the use of a heat pump to supply both heating and cooling. While the electric rates are high, and likely to go even higher with Obama closing down coal fired electric generating plants (we just lost one two years ago), I know my auxiliary wood fire furnace is definitely going to be needed to offset fuel costs during those cold winter nights. Another problem with an electric heat pump, if we lose power, which seems to be happening more and more, and the down time can be measured in weeks rather than days, there could be a serious problem trying to make do with small emergency gasoline generator and keep warm at the same time. In addition, even though I winterize my 3500 watt generator, and it has always started up for me, I have little trust in anything that uses our mandated E10 crappy fuel.

    The electrical load to operate a wood fire furnace and its associated blowers is around 15 amperes at 120 VAC. Even without power the wood furnace could be operated as gravity unit with a greatly reduced output. Not sure what that really means but I suspect its 50,000 BTU rating would have to be reduced to something around 10,000 BTU at the most.

    I do have a Chinese made kerosene heater (I wish I had a kerosene heater made in Japan but they have given up on the USA with our insane libel suits) that can provide 30,000 BTU but really do not feel very comfortable about its use in an emergency and consider this to be a last resort procedure.

    The only other heat source I can think of for consideration is an outside propane tank. Have no experienced at all in propane heaters, and propane is expensive, but considering the liability one could run into with a leaky oil tank, it is up for consideration. I do not know if it would be possible to tie into the heating propane tank a whole house emergency electric generator using propane as a fuel to keep things going if the power lines should go down.

    Once I get rid of the lovable Williamson monster, two large units, burner and fire box alongside the blower cabinet, there should be plenty of room left to stick anything else in the space that I desire.

    Please help me out here; should I go with just a heat pump, or a heat pump combined with propane heat, perhaps just air conditioning and propane heating, or even just a heat pump with a propane fueled whole house generator. In all cases, my wood furnace will still be there. Cost is important, but something has to be done, and I do need some advice as to a plan of action.

    For the solar types, please, my life is complicated enough right about now and the payback for solar will likely never come for a 75 year old.
    Last edited: Jan 11, 2014
  2. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,006
    Location:
    New England
    Good mini-splits should handle your place both for heating and cooling. The big thing is to figure out what size you really need. The choice can get a little complicated depending on the floorplan of the house...the more open it is, the easier and less expensive it will be since you need fewer heads or units. The good ones provide heat at much lower temperatures than the older ones. They would free up space in the house as well. Read a few similar threads here and you'll get enough info to start to evaluate what's going to be required.
  3. melcohvac

    melcohvac New Member

    Messages:
    1
    Location:
    Florida
    Mini splits aren't really ideal for cooling and heating an entire home. The most glaring issue is the scacity of warranty parts because the majority of these are manufacturerd west of Hawaii. You also won't find a high percentage of AC contractors that know much about them either for a number of reasons. There are additional drawbacks that include higher installation costs and shorter warranties than standard central heating and cooling systems.

    The best advice is to call a licensed contractor you trust. The call is impossible for us to make from here that can not determine your heating/cooling load, compare electricty/propane costs etc. Any forum advice should be taken with a grain of salt including mine. My opinion is that you will save more money in the long run by installing a heat pump and that it will suffice in conjunction with the furnace but again, I'm not looking at it.
  4. Scup

    Scup New Member

    Messages:
    43
    Location:
    Stonington, CT
    I had reasoned that since all the duck work is in place I would go with a central heating system. Unfortunately, I have called a licensed contractor, and while I cannot say he is not trustworthy, I am concerned since I have not needed much in the way contracting over the years, and when I have hired so called professionals I usually ended up thinking I could have done a better job of it myself, but not always.

    For example, excavators (heavy equipment operators) in my area have always been extremely professional, concrete contractors have varied from being great to where I had to have a footing removed because one team must have put it in when when some of them were drunk. Very good experience with carpenters, roofers, duck work men, and sheet rock guys. When it came to plumbing, the first plumber I ever hired was a young man just starting out, to rough in all my fixtures, he did a marvelous job. Then with future licensed plumbing and heating contractors it went all downhill. Had a side shot unit put in to exhaust my oil burner that came on when the air conditioner lit off. A hole was made in my foundation wall for the unit not with a carbide/diamond drill but with a concrete pavement breaker.

    I have noted that whenever I hired a contractor to tune up my oil burner, it would fail that very heating season. I could not understand how a relativity new Williamson Furnace could operate so poorly and fail so often. Each time I had gone to a different contractor thinking that sooner or later someone would know what the hell they are doing. Finally in total disgust, I called up Williamson about the problem. They immediately sent a rep out to my house at no charge to analyzed what is wrong.

    The fire chamber had to be replaced due to the installation of an improper blast tube, and likely carelessness when cleaning. The wrong nozzle was installed. The electrodes were set so far behind the nozzle, the rep explained that he was surprised that the unit would even light off. Even worse, the replacement electrodes were so short that it would be impossible to even adjust them properly. The air mixture was set wrong.
    The rep wanted to know who did the work, and I would have told him if I knew, but since I had hired so many different contractors it became problematic as to who did what. After the repairs were made that the Williamson Rep had found the unit purred like a kitten.

    In disgust, I purchased a $700 oil burner tune up kit and started to do the tune ups myself, even though I still do not know what I am doing and to me that is very scary. Although do give me some credit in that I can change an oil filter, I do know how with wire up a side shot that comes on when the oil burner starts and not the air conditioner, I can read specifications and ask for the proper nozzle for my burner, and likewise, purchase the proper electrodes and follow Williamson's adjustment diagram.

    On my very first post that I have ever made on this site, I stated I am not a people type of person, and probably many members will now definitely agree with me. Heating and plumbing has always been a very difficult item for me since this is not in my area of expertise. However, it seems through my inability to hire or find trusted contractors that I have become much soured on this profession.

    Quite to the contrary, on this form I have received several personal emails from members who after reading my posts, wished to provide a novice with information and their only purpose were to set me straight. I can read the back and forth arguments on another post concerning the disadvantages/advantages of say a CSV. Not that difficult to understand what they are saying and why they are saying it. The information posted by so many on this form I do digest, then think about it, and finally hope that I have come up to speed enough that when I do talk to contractors I at least have an idea that he might trustworthy.

    I fully understand that the contractor that came to my home who praised propane heat might have been correct, or it might be a high profit item for him to sell. I am sort of starting out as a total blank sheet of paper here but even from the just the two posts made, I decided that going with a few ductless air conditioning units would be foolish considering my Modified A frame has a more than an adequate ducting system already in place. I am not particularly fond of systems for which decent replacement parts are not available either as I recently found out those offshore products may or may not come up to snuff.

    As far as calculating loads, well I am not starting up from scratch here since I know what I now have, how well it performed and how my home is insulated. I know that my Five in one Williamson unit is overkill for my home. My little Bison wood furnace, maximum output rating of 50,000, BTU can bring the house temperature up to 65 degrees assuming it is 0 degrees outside and windy. One must understand that it is just about impossible to get maximum output out of a wood furnace unless you are standing by it, feeding it well dried ash, mixed some heavier heat producing wood like oak or hickory, shaking out the ashes, and continuously watching the stack thermometer to prevent over heating the fire box. I believe a more conservative practical estimate of 40,000 BTU would be in order. I do not need a 150,000 BTU heater. When I start my 37 year old Williamson air conditioner, it has gotten so cold so fast in my home (my wife likes it that way) that I had to put a small electric space heater under my chair. I do not need a central air conditioning system that requires 50 ampere service. While I have not measured it (although I could), I suspect that the air conditioner does not even draw 40 amperes when the compressor is running at high speed.

    When I talked to a contractor about loading for the possible installation of a heat pump, he explained that I would need an additional 60 amp 240V service since my 50 amp service already in place would only handle the air conditioning. After doing a quick mental calculation 240 X 50 is 12,000 watts. That is over 40,000 BTUs per hour. I find it hard to believe that a heat pump requires two different services, since what engineer would design a unit such that it would have to pump heat and cool at the same time. Again, I really do not know what I am writing about since this is not my field but something is not right here. The contractor also refused to attach my wood furnace into the ducting explaining that the evaporation pan in the heat pump is plastic and would melt, and it would be very unlikely he could find one with a metal substitute. This winter I placed a temperature probe on the pan, ran the wood furnace at 1000 degrees stack temperature and measured just less than 90 degrees. Perhaps some plastics can melt at lower than 90 degrees but I do not think anyone would use such in a heat pump.

    I find picking a trusty contractor is beyond my capabilities. I know they are out there, but even after I have talked to them, listen to what they had to say very carefully, take notes, research what they claimed it still seems I get behind the eight ball way too often.

    I have tried referral services and the free ones are nothing more than an advertisement vehicle as one of the real losers I had hired was on the preferred list. I have not tried the paid referral services as their advertisement on TV really turned me off as I could give a damn if my plumber walks my dog or not.

    I really believe I have learned far more at this site in a month than speaking with the so called trusted contractors. What is strange, I believe of all the posts I have read on this site, have come from honest people trying to help out, whether they are in the business or not, and while some answers and solutions may not sit quite right, that is fine by me. Honesty to me looms far and above a good cock and bull story.
    Last edited: Jan 12, 2014
  5. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,006
    Location:
    New England
    A traditional heat pump will usually have electrical resistance emergency backup heaters...those would require additional electrical service, should they be required. But, the efficiency of many of the new mini-splits are that they produce decent heat way down, much colder than the old ones. I do not know if they still have those, as they may no longer be needed. So, that discussion may be apples and oranges.

    If Dana doesn't pop in here, send him a PM. He has done a lot of research on these things, and if you read around on the forum, there are bunches of discussions on them.

    When I did look at them, I do not remember them needed excessively large amounts of power input.

    FWIW, some of them can output into your existing ducts, if I remember properly.
  6. Scup

    Scup New Member

    Messages:
    43
    Location:
    Stonington, CT
    I understand that heat pumps become more and more inefficient as the temperature differential drops say from 68 degrees in one's home to something above freezing. At an outside temperature of say 50 degrees, they will transfer more BTUs per hour into your home than the equivalent wattage they use which is a good thing. There is some low temperature (I do not know just where it is since I am sure the technology is improving all the time) for which a heat pump can no longer be practical, hence, it will resort to a resistive type of heating. That is why I ran my calculations and my required heat load and came up with figure that 50 amperes @240 volts should be more than adequate to heat my home properly even if the temperature drops to zero degrees at which no heat pump could work effectively at.

    I do not understand why two services of 50 and 60 amperes are required. I find it hard to believe that electrical engineers (I happen to be one) could not figure how to stop a compressor from working when a certain low temperature is reached where it becomes so inefficient that it becomes impractical to operate, hence its rated load has to be transferred to resistive heating.

    To be sure it would be slightly simpler to have an independent resistive heating in place and just turn it on and off as needed. However, whole house emergency generators can transfer electrical power quite nicely, safely, and automatically when needed. For example, your home is being powered by Con Edison and some nut drives into a pole and your home loses all electric power. A transfer can be immediately and automatically made by switching your home (the load in this case) previously on Con Edison's system to the output of your emergency generator in little more than a couple of seconds that it takes for the generator to kick in and get up to speed. What you are describing is a system in which it would be simpler to always have your emergency generator running all the time and hooked up to your heating load thus the only thing necessary in an emergency would be to have your heating loads turned on.

    I am not saying you are wrong, and it certainly is no big deal to run an extra 60 amp service, but I am somewhat surprised that my peers could not figure how to redirect electric power quickly, safely, and automatically when needed. I cannot help but think about when a diesel/electric submarine (yes I am that old) has its snorkel covered by a wave, the diesel can only drive the electric propulsion system for a short period of time if the snorkel does not recover since it needs air operate. No air, diesel no work! It has to be cut out before it stalls or busts every bodies ear drums because it will draw an vacuum. I have no idea of how many thousands of amperes are automatically transferred to the electric propulsion engines from the diesel's generators which had been shut off to a battery bank and all of this is done in seconds, automatically, and this is World War Two technology.

    Good thing I joined this form, because I would never have believed that two electrical services are needed for a heat pump, one for the heat pump and is associated compressor/motor and a second for a semi independent resistive heating system.
    Last edited: Jan 12, 2014
  7. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,006
    Location:
    New England
    Some of the better mini-splits produce decent heat at -15F...they do turn off the compressor once it gets to a certain level, and a more typical mini-split will probably run on a 20A circuit. An older heat pump might have trouble once things got to freezing, so the technology has improved. A conventional heat pump will probably still need a separate air handler, and in that, they may have a bunch of resistance heaters.

    When you start matching the heat load to the heater, they have less makeup capacity...i.e., while they may keep the house warm, they may not be able to reheat it quickly after a setback. This is where the resistance heaters may become more critical.

    FWIW, the two services are more likely one for the heat pump, and a second one for the air handler, where the resistance heaters are. In a mini-split, they run off one feed, and the ones I've seen are no where near that big. The best ones are from some of the Japanese brands, but some aren't far behind.
  8. Dana

    Dana In the trades

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    2,840
    Location:
    01609
    Ductless mini-splits would have a seasonal average of about 3.3-3.5 in a southern CT climate, and cost less than half to heat with than an 85% combustion efficiency oil burner, even at CT electricity prices. (An NEEA field monitoring study that included a cluster of ten one-ton Mitsubishi Hyper Heating mini-splits in Idaho Falls averaged a COP of 2.96, in a climate where the AVERAGE winter temperature is only 3-5F above the 99% outside design temps for coastal CT. I can point you to the final report if you want to wade through the ~160 pages of it.)

    BTW: Regarding electricity prices- coal fired plants are significantly more expensive to run than the combined-cycle gas units that have replaced them in CT/MA. This is due to both the near record low price of natural gas, and the fact that they cc-gas generators operate at 2x the efficiency of thermal-coal. This isn't much affected by executive branch energy policy or even EPA air-pollution issues, as much as the coal industry folks would like you to believe otherwise. Fracked shale & coal-seam gas is what's doing-in the economics of coal, an ongoing development for several administrations. (Love him or hate him, Obama only WISHES he could take credit for cheap natural gas, and non-rising coal production numbers. Only in 2012 did US coal production begin to decline, and that was due primarily to combined cycle gas plants coming online, the sober decisions of utility operators looking at 25-year price projections.)

    But if your house doesn't have a very open floor plan it can be difficult to heat with ductless. But even heating 1-2 main zones with mini-splits and sparing-use of resistance heating for temperature balance in the doored off rooms is still pretty cheap.

    Middle-of-the road 1-2 stage heat pumps might work, but would run at an average COP of about 1.5-2.0. A better class fully modulating Carrier Greenspeed ducted heat put would run at near mini-split efficiency, but at a fairly high up-front cost, and may have capacity issues if your house isn't very tight.

    To get a handle on your heat load in order to size ANY new system, it's fairly straightforward if you have a winter oil-bill with a "K-factor" stamped on it (best) or annual gallons usage (very crude) and a zip code to verify heating degree-day and outside design temp numbers.

    It's unlikely that your heat load is truly 40,000 BTU/hr, but even if it were, that load could be met with a pair of Mitsubishi MSZ-FE18NA 1.5 ton mini-splits, that would pull less than 40A (20A per) @ 240VAC running flat-out, and a heluva-lot less on average. Being fully modulating systems with DC motors and scroll compressors, you have nothing like the startup current issues you have with reciprocating on/off compressors. The interior heads are barely louder than your refrigerator at max-speed, and whisper-quiet at low speed, much quieter than most ducted systems. The Mitsubishi FE "Hyper Heating" units, as well as the Fujitsu RLS2-H "Halcyon XLTH" series have rated outputs at -13F (much colder than it got during the recent cold-snap). Even at -13F and running full speed they are running at a COP of 1.8- which is roughly the all-in efficiency of most on/off ducted heat pump systems at +20F. At part-load modulating at lower speeds the efficiency soars.

    With any ducted system it's important to seal every seam and joint with duct mastic, and tape up the seams of the air handler with FSK tape, insulating at least the supply ducts to R6 (more if they run outside of conditioned space, such as an attic.)
    Last edited: Jan 13, 2014
  9. Scup

    Scup New Member

    Messages:
    43
    Location:
    Stonington, CT
    Thanks Jim and Dana,

    You have me feeling almost embarrassed that you would have spent so much time on a complete stranger in answering so many questions and in such detail. While I do have a strong technical background, I tend to be a slow but exacting reader when adsorbing technical information. I will probably have to read and reread the material presented and even then asked for clarification on some points.

    The non technical part i.e. Dana's second paragraph describing the decline of coal powered electric generating plants is simple enough to understand with the first reading. My incorrect beliefs came about because of miss-information being promulgated from various sources. I saw two coal powered electrical generating plants go cold iron very close to areas where I had worked. The first was the Montville CT generating station, which was disassembled and sent to South America and the second was the Dresden Plant NY, (located on Seneca Lake) that was reported to have been shut down because of operating costs. It had been reported both ran afoul of very restrictive pollution standards. That was fairly easy me to understand and accept, even if it was not accurate. Dana's explanation makes far more sense to me.

    What impressed me most was Jim’s statement as to the very low temperatures these modern heat pumps can work at, and Dana's statement concerning the cost of operation even with CT’s electric rates and the conformation of Jim's claim.

    I hope neither of you will be sorry for responding to me since I just might end up being one big pain for both as there are going to be quite a few forth coming questions.

    Perhaps it is proper that I should describe my inner concerns so you can understand why I am so very worried about going about and getting things done properly. I have really done poorly in getting/selecting honest contractors in the past so I realized far better attention has to be paid to future selections.

    Though my eyes, I see my home as a mess. Being an electrical engineer, I have always been around to do or correct items that have needed attention. When things have gone wrong, repairs were needed, or mistakes had to be righted, I was there to correct whatever the problem might be, either directly (most of the time) or through contracting. Recently, being seventy five, my loved ones would not allow me to climb to the top of my A frame roof to clean out our chimney or even drop down into our dug well to replace a pump.

    The chimney ended up being cleaned far better than I had expected, but the pump replacement went really badly, expensive, and may have to be redone; only time will tell.

    The co-occupants of my home, wife, son, and daughter, have all declared their desired to remain in our home no matter what. I really cannot see where there is a pathway in which my loved ones could survive for very long without someone being around to keep things running. I had recommended they sell the property in the event I am no longer around, but they remain steadfast in their wish to remain together and continue to reside in the home they love. Whether I think it is advisable or not, I find myself on track to correct things in my home as much as possible, get rid of aging utility systems that I have kept running using bailing wire, and get our home in a reasonable condition such that future maintenance and operational costs will be minimal.

    The above is why I joined this site, and will be grateful if you bear with me as I absorb the useful and needed information you have presented.

    I do wish to take one step at a time and this would be my first concern: should I get rid of my entire oil fired Williamson Five in One hot air heating system(its corresponding duct work I do not consider to be part of the system)? While the system is still operating, my wife told me our home was built in 1983 (I had thought we built it in the seventies), but still, the entire system is pretty old. The cost of oil has sky rocketed in my area, and having no room for an inside oil storage tank an outside tank was in order. The replacement costs of an outside oil tank (necessary to prevent leakage) was high, and keeps climbing upward. The tank itself is not costly, but the paperwork/documentation, charge for reclaiming or to get rid of old oil, recording test results with the town hall, and all of this was done even though I have never leaked a drop of oil, really makes one question the sanity of staying with oil in my area because of its enormous liability concerns. The maintenance costs have been high as well, requiring servicing and replacement parts and while I do not wish to create any criticism from local oil heating contractors in my area, my experiences with them over the years, except for one, have not been favorable. If you feel that a private notification is in order here, I will always keep such confidential.
    Last edited: Jan 14, 2014
  10. Dana

    Dana In the trades

    Messages:
    2,840
    Location:
    01609
    Get rid of the oil-burner- it's just an expensive to operate liability at this point.

    There are heat pump solutions that may be able to utilize the existing ductwork, but you may need to at least seal and insulate the ducts to get you there. But to make a sane decision on the sizing we need to zero-in on the actual heat load. ALL oil-burners are oversized for the heat loads of mid-sized 1980s house, but that's definitely not the case for heat pumps. The very best heat pumps (like ductless mini-splits) will come in at about half the operating cost of heating with oil. But even a right-sized 2-stage would still be a net savings. (You'd have to be drinking the frack water to believe heating oil is going to average under $3/gallon for the next 20 years, given the rising demand for oil & oil products from the developing world.)

    Any new equipment is best sized for the "after" picture of fixing all the low-hanging fruit on the building envelope, so now's the time to figure that stuff out. If your kids are planning to live there for another 40 years, it's worth dealing with those things sooner rather than later.

    If your house was built in 1983 it's probably 2x6/R19 construction(?) which isn't terrible, but it probably leaks a lot of air and has no foundation insulation, and depending on both the air-leakage at the foundation sill/band joist (usually THE largest leak in a house that hasn't undergone blower-door directed air sealing) and the amount of above-grade foundation it could easily add up to 25% of the the whole-house heat load. In many houses the foundation's heat loss is over 10,000 BTU/hour if uninsulated, but drops to about 1000-1500BTU/hr with insulation. To insulate a basement without introducing mold issues it's important to get the particulars right- you can search the "Remodel" section of this site for details- it's a subject that gets covered regularly.

    If the attic has only the typical R19s rolled out between joists or 8-9" of blown fiberglass, it's worth topping it with 6-8" of blown cellulose after air-sealing the attic floor/upper-floor ceiling. Masonry chimneys on exterior walls can often be a big heat-leak, but are a bit more complicated to deal with. Masonry chimneys that cross through the interior often have chases that are open from basement to attic, which de-pressurizes the house, sucking outdoor air in. This too can be air-sealed (with sheet metal as the air-barrier.)

    1983 vintage clear-glass double-panes have a U-factor of about U0.6-0.7, and it's expensive but still cost-effective in the long term to add tight low-E storm windows over the outside, which will cut the heat loss from windows nearly in half. At an interior temp of 70F, exterior temp of +10F ( about the 99% outside design temp in Stonington) that's about 400BTU/hr of peak load for a typical 10-11 square foot window, and adding a low-E storm would drop that to under 250 BTU/hr a reduction of about 150BTU/hr for a typical double-hung. (They make low-E storms for picture windows too.) Harvey Tru Channels are the tightest in the industry, and they ahvea low-E glazing option, but the Larson low-E storms sold through box stores aren't terrible if you upgrade to the Silver or Gold series (the Bronze series are too leaky, and have crummier hardware.) It's less than half the cost of a replacement window that would have the same performance, even cheaper than the installed cost a code-min replacement.
  11. Bob.Small

    Bob.Small New Member

    Messages:
    1
    Location:
    CT
    Dana, I tries to send you a message your inbox is full. Do you do consulting? Give me a call if interested 203-996-8598
  12. Dana

    Dana In the trades

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    Location:
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    I'll clear the message box- try again.
  13. Scup

    Scup New Member

    Messages:
    43
    Location:
    Stonington, CT
    Dana,

    My house is a modified A frame, modified simply means the pitch of the roof is a 45 degree slope, and never drops to anywhere near ground level. You are right in how it was constructed with 6" studs for the exterior wall and filled with insulation of R19. Being an A frame with no attic, the insulation is in the roof and while I cannot recall the size of the rafters I expect they were at least 2 X 8 (likely 2 x 10) and filled with insulation. There are foam spacers placed in the rafters their entire length to guarantee that the insulation would not completely close off the ventilation, since there are breathable roof ridge caps running the length of the roof and corresponding vented eaves.

    The basement is walkout (complements of Stonington which is appropriately named) since ledge determined just how far down the footing could be placed. At least three blasters and one hydraulic rock splitter contractor (lost count of the number of excavation machines needed, but every inch of footing depth had to be fought for).


    I would estimate about 3/4 of my finished basement is above grade with a screwy method of being insulated. Since it is a finished walk out basement, I used 2 x 4s around the inside perimeter just so I could install electrical outlets, telephone, and TV cabling. When the insulation contractor came everything was insulated and 6 mil poly stapled to the studs before the sheet rock was installed. The basement floor is not particularly cold, but that was not insulated. I did place 6 mil poly down before the concrete floor was poured which really pissed the contractor off since he had to leave the floater guy there for 6 or 7 hours because the poly slowed down the curing process, which is why I placed it there. I threw a decent bonus at the guy to keep him happy.

    The below grade part of the foundation has 1" (maybe 2" cannot remember) foam stuck to the outside walls. I did not put it there for insulation but when they back-filled, I was really concerned about the size of some of the rocks in the mix and simply pinned the foam there as a cushion should something go wrong but nothing did.

    I have no idea how tight the place is, but even with Sandy blowing I did not feel any drafts with the exception of the air input pipe for the wood furnace which was needed. I have a lot of twin pane glass on the south and south east side of the house but little elsewhere. In the summer, the large glass area would definitely increase the cooling load (it gets hot in the loft if the air conditioning is not on).

    I have no idea if we have a mold problem so I asked my wife since she is the one that goes into all the dark crevices to clean. She has never seen any. I do have mold on the outside of the roof shingles, and small amounts form on the North side of the house, but that is a very common problem living on a salt water marsh, and most of the homes will sooner or later develop this problem unless mold resistant shingles are used.

    The electric company did calculate my heat load (I might even be able to find it) but oil heat was about 1/3 cheaper back then than electric heat so while the house was insulated for electric heat it never came to pass.

    The rectangle base of the basement is approximately 42 x 26 feet on the outside but subtract about two feet from that for the inside since 10 inch concrete walls plus a wider lip in places for brick veneering in addition to the 2 x4s studding.

    The only place the duck work is insulated is the run from the basement to the loft.

    Question: Since the whole house is heated/cooled, I do not understand the concern for insulated ducts. All supply ducting has adjustable air valves in them. I used to screw around with them initially i.e., get the bathrooms a bit warmer and fuss with some in winter versus summer but nobody has complained in years so I stopped messing with them. I do have a two zoned hot air heating system in which two air valves that look like a Venetian blind open and close (they still work) but I am not sure if they ever were really needed. In simple words, if my home was a ship, there are no voids or unmanned spaces.

    The chimney is a massive brick affair centrally located in the middle of the house and it seems to hold the heat quite well long after the wood furnace dies down. Unless it is well below 30 degrees, we usually let the thing die out during the night since I am very comfortable with my electric blanket, and my wife prefers a 63-66 degree room temperature in morning anyway.

    I think you are probably right Dana, that my heat load is probably less than 40,000 BTU.

    When the outside temperature it gets into the 40s, we sort of sometimes get lazy and instead of lighting off the wood furnace, we just use a small 1200 watt space heater in the den area where we are.

    If it is sunny out, we rarely have to fire off the wood furnace during the daytime if the temperatures are in forties or above.

    Strange but my wife and I both like the heat from the wood furnace rather than the oil burner. The burner seems to come on, then shut off, come on and then shut off, it does not happened often but it sort of reminds me of the operation of a water pump needing a Stop Cycle Valve. With the wood furnace everything happens very slowly and does not jerk one around with ups and downs in temperature. The main problem with the wood furnace is it is like a baby always requiring attention. It is a lot easier just to turn a thermostat knob, but over the years we have become accustomed to heating with wood.

    Likely we have become very careless in worrying about some BTUs being lost here or there since I have notified everyone on my block that I heat with wood including a couple of storm clean up contractors. Hence my property is typically used as a drop off point for hardwood after a major storm and we seem to have one every other year. I do not really buy firewood but try to find out who left what and then compensate them for their trouble. There is some concern on my part that likely no one in my family but me would likely stack 1500 pound bolts off the ground for seasoning, split, stack, and cover wood piles, and fill the small wood storage ricks for immediate use.

    I have thought this out and reasoned that I cannot do everything for everyone from a grave, so I will try within my means, to modernized utilitarian systems as best I could for them. I wish for them to have a suitable home, but they do have to take some responsibility on their own. Very likely, they will not be able to maintain a home, as they have not yet even figured out that leaving on eight outdoor flood lights all night is not cost effective. I cannot see into the future but perhaps when they come to the realization of having to pay the electric bills things might change.

    We understand your recommendations that a house should be properly sealed and insulated even before consideration is given to the selection of modern heating/cooling equipment. If not done in the order you described, it would be impossible to have everything operating in an efficient balance.

    As with most homeowners, there also has to be a balance between what one can afford, what is necessary, what is practical and what one would like to have. One would think that even the personalities of the final users could easily come into play. I have been asking friends who own heat pumps and so far one contractor, concerning the costs of heat pump installations, and while my friend thought they were very expensive it seems to me these modern units with their incredible performance capabilities, are very reasonably priced and manageable. However, because of the exacting information provided by this form, especially from Dana, I now realized there has to be a much bigger effort on my part to digest what was suggested and I have to spend quite a bit time looking up specifications and getting manufacturer's literature.

    Dana, you overloaded my small mind; I never realized the capabilities of these modern units have advanced so far so quickly. Modulated direct current motors, well why not as I suspect the development of high powered mosfet and solid state controllers made this possible. What next, AC to DC power converters powering a solid state variable frequency AC power source driving AC induction motors or have they already done that? Almost sounds like a propulsion drive system for a ship. You have convinced me that I have to have one or two of these heats pumps installed. Now comes the hard part, tying to pick a Trusted Contractor.
    Last edited: Jan 15, 2014
  14. Dana

    Dana In the trades

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    Using batt-insulated studwalls with interior poly on the sub-grade portion is risky, sinces it traps ground moisture in the studwall. But with big roof overhangs and 3'+ of exposed above grade foundation it's not too bad. A 2x4 wall with R13s comes in at about R10 after the thermal bridging of the studs are factored in, which is OK, not great. If there's room for 1.5" of foil-faced polyiso on the interior side, that would DOUBLE the thermal performance of the wall. The vast majority of the wall losses are at the above-grade portion, but any time you're re-modeling or fixing up a new section, it's worth it.

    With an A-frame the majority of the exterior surface of the house is roof. As long as there isn't any interior-side poly sheeting in the roof stackup, next time you re-roof it's possible (but not cheap) to dense-pack the vent channel with cellulose as long as you put R20 of rigid foam on the exterior of the roof deck under the new shingles. (That's 5" of EPS, or 3.5" of polyiso) In New England there are multiple vendors of reclaimed roofing foam (insulation depot in Framingham MA is just one of several- check the Hartfort/Worcster/Providence craigslist materials sections and you'll find some of the others.) Reclaimed foam is about 1/4-1/3 the price of virgin stock. It can be tacked in place with foam board construction adhesive, then permanently held down with half-inch OSB through-screwed to the structural roof deck 24" o.c. with pancake head timber screws. Once the foam is up there, with dense-packed 2x8 cavities you'll be looking at about an R45-R50 roof, which is probably better than 2x the performance of your existing roof.

    If it's a fairly open floor plan you can get 90% of the way there with mini-splits as-is. You are correct in your presumption that the high-power mosfets are a key technology of the high efficiency "inverter drive" DC motors used in all better-class mini-splits. It's essentially "switching power supply" or "class-D amplifier" technology, applied to permanent magnet DC motors.

    Being fully modulating systems mini-splits always "play nice" with wood burners and other auxilliary heaters. They do least-well with forced hot-air systems, which can deliver rapid variations in local air temperatures. To make it work nicely with force hot air placement the ductless head where it's well out of the drafts becomes critical. But mini-splits deliver EXTREMELY STABLE room temperatures on their own when operating in their modulation range. The turn-down ratio is about a 3:1, sometimes 4:1, so as long as you don't oversize it by more than 30% or so it'll be modulating and running nearly-continuously through most of the winter months, and on-average will use slightly less than 1/3 the electricity of electric baseboards or other resistance heaters in your climate.

    If all ducts are completely inside the thermal and pressure envelope of the house they need not be insulated, but air-sealing them is useful for getting the heat to where it is actually intended.
  15. Scup

    Scup New Member

    Messages:
    43
    Location:
    Stonington, CT
    Question for anyone!

    Question for anyone!

    I understand the need to have a well sealed home as that will ease and improve the heating and cooling loads. In addition, there could be a host of other problems that are either alleviated or introduced depending on how it is done. I am not sure if there are codes specifying that a bathroom should have a force draft external fan but all of my bathrooms have working windows instead. My electric kitchen stove has a hood, with a filter and fan that goes nowhere! The cooking odors just get circulated through the filter. I would also assume that many homes might still have resistance heating in them as well, which does not require an air change out to operate.

    However, from my own personal experiences working at a DOD research facility in New London CT, we had a major problem in one building with basically stale air (I do not know the proper term to use for improper exchange of air within an office building). Engineers and scientists were falling asleep at their desks, at least 25% of the people reported headaches, coffee breaks were getting longer and longer and occurring with greater frequency; extended coffee breaks at a government facility is not normally an unforeseen situation but people where having these breaks outside of my window during winter rather than in the usual interior spaces.

    Understand this building was a typical office building, offices around the perimeter with fixed windows that could not be opened, and with the usual interior cubicles dividing up work areas. Occupants had no control of heating, cooling, quality of the air, no thermostats could be manipulated, and even if one wished to have a small AC circulation fan in their cubicle that would require prior approval.

    Speaking with public works, who maintained and controlled the heating, cooling, and ventilation systems, I was told their hands were tied, there was a very real problem in air change out, but there was no way they could improve the situation because of the way the system had been designed.

    I understood Public Works had no recourse to correct the situation but our Safety Engineer did. It was discovered he was informally told time and time again about the problem and did nothing. I forced the issue by sending him a memorandum explaining the situation, and for the distribution list, I included everyone. The Commanding Officer was on the list. I must have ruined the safety engineer's day because he now had to respond which he did in writing a few days later.

    His written response included the recommended air exchange rate for our building (I did not even know there was code addressing this issue) and he either calculated or measured (hard to tell how he did it from his response) the existing air exchange rate in our building and it was a fraction of what it should be.

    Thinking that this would be it, everyone expected the problem would be taken care of. Weeks later, nothing happened to correct the situation other than a couple of engineers blocked exterior doors to stay open. Being really upset; I marched into the Safety Engineer's office with his written response in hand and asked, WHY! He explained that even though I had read his response, I did not understand what I was reading. The code had recommended what the air exchange should be, but it was not mandated!

    My question is now this: since a home is a complex blend of various systems working together, one must not ever forget that people play a very important role in this makeup and they too have their needs and have to be able to operate within certain parameters: how do modern homes (or even older ones) insure the occupants are being properly cared for?

    Again, I do not know if the codes have changed, perhaps far more consideration is now given to the occupants? Is there now code mandating the air change out, specifying either passive or active venting systems, or must one fall back on air leakage or the opening or closing of windows?
  16. Dana

    Dana In the trades

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    Code for new construction calls for exhaust ventilation for both kitchen and bath rooms, but there isn't anybody making you use it. In very-tight well insulated house heat recovery ventilators (HRV) operating at a duty-cycle is a common solution to indoor air pollution.


    In those homes it's common to have only exhuast registers in the kitchen & bath areas, and use jump-ducts or door-cuts as the ventilation path for those rooms. That keeps the odors & humidity from being drawn into the other spaces. These are very tiny ducts by heating & cooling stadards- 4-6" trunk lines, with 3-4" branches, and are pressure-balanced when commissioning them so that the HRV neither pressurises or depressurizes the house so that it doesn't drive air infiltration via other paths. Internally they have a counterflow heat exchanger to pre-condition the ventilation air to nearly the same temp as the exhaust air, and are EXREMETLY efficient from a sensible-heat point of view, but they do not preserve the humidity balance. Their close cousin the energy recovery ventilator has a moisture exchange as well as a sensible heat exchange, but the moisture exchange isn't nearly as effective, but still better than nothing in a CT climate given fairly high summertime outdoor dew points.


    Under IRC 2012 houses that test tighter than three air exchanges per hour at 50 pascals pressure (aka " 3ACH/50" a common blower door test pressure) require mechanical ventilation. Under IRC 2012 all new houses in New England need to test no more than 3ACH/50, which means all houses will be required to have some sort of active ventilation that can be run at ASHRAE 62.2 rates or higher (though there is no reason to actually run it that high under normal circumstances- maybe when you have the gang over drinkin' whiskey, playin' cards and smokin' cigars it might make sense. :) ) While HRV isn't mandated, it's the most energy-efficient. Exhaust only systems can work, but require inlet ports at every room to truly meet spec. A retrofit HRV system could run as much as 4-5 grand, sometimes higher, but in new construction it's usually less than that.

    Tight house or not, the indoor air quality of ALL houses can be improved with ventilation systems. The air leakage into your house isn't guaranteed to be the locations that need it most, and could be coming from some less-great space, like a garage or a fetid crawlspace full of mold.
  17. Scup

    Scup New Member

    Messages:
    43
    Location:
    Stonington, CT
    I cannot remember if there is poly or not on the inner side of the rafters. If there is a problem it has not surfaced. However, I do not know what I should be looking for?

    The overhang extends from 4' to 2' since it is tapered. Unless there has been say a failed pex fitting, there never has been any water entering anywhere. Although Sandy did have me concerned; she never even came close to coming inside. Again, it was impossible to get the home dug in as deep as planned because of ledge. The footing area consisted of sand between pretty solid ledges. The footing itself had to be engineered, acting like a girder, to span the sandy areas while being pinned to the ledge area. There are no cracks anywhere in the foundation walls, at least as far as I know. When tests were done for the placement of the septic system it was difficult to measure the rate of how fast the water would exit the test hole. Being mostly sand, no clay whatsoever, I can still remember running down to the cove to get a couple of five gallon pails of water and dumping it into the test hole and the water would disappear pretty fast. The contractor had his watch out but he made me run back and forth to the Cove a half dozen times to keep filling the hole so he could get the measurement for the town hall. Probably why I never had exterior water becoming an interior water problem is because of good drainage. More recently, I helped a neighbor install his leaching field, and his leaching field had to be so enormous one would think it could handle a small motel. The code has changed so dramatically that I am pretty sure my system is grandfathered in.

    The roof is fairly new, so it is unlikely anything is going to be done here.

    I really like the idea of these high efficiency mini splits but the floor plan is fairly open for only the living room, which is not even used much by occupants. The ground level den/dining/kitchen is the most used portion of the house but certainly is not very open. The loft can present another problem as well as it is not driven by heating but cooling. There is a massive return vent at the highest point of the cathedral ceiling, since by natural convection heat just rises up to the ceiling. Once the heat is sucked up, it is returned to the ground level Williamson air conditioning unit where it gets cooled, and then through two insulated ducks running all the way back up to the loft. I am not always a loser, as the contractor I hired who did the duck work seemed to know how to size things up and to be able to provide heating and cooling effectively throughout every room in the house. I really think I am stuck with a centralized heat pump since the existing ductwork appears to be very accommodating for what is probably a very difficult home to size up correctly.

    Is it possible to obtain a decent single centralized heat pump that can be tied into the existing duck work? I understand this is likely not the most efficient solution but it just might be the most practical one. I do not ever plan to use the wood furnace while the heat pump is operating. Obviously one would not need the furnace during the summer, nor would there be a need for a heat pump to be operating in the winter should the wood furnace be putting out. There is a need, however, for the main distribution blower within the heat pump to be independently turned on via a single set of contacts to distribute the hot air (just under 90 degrees) throughout the house.

    The contractor I spoke with seemed totally lost and obviously wanted to do things his way avoiding the simple auxiliary tie in. I assumed that your modulated DC motor, if used in a centralized heat pump, would be the compressor's prime mover since this is the workhorse, and the air distribution would be a simple squirrel cage blower/motor? If not, then I really have to get some schematics to figure out just what is happening in these units.

    Dana, if I am pressing you too hard for information, let me know and I will quickly correct such. I am consolidating your posts and placing them in a folder for my children. At least they will have an instruction booklet of what they should know and be doing. Thank you very much for the help you have already provided.
  18. Scup

    Scup New Member

    Messages:
    43
    Location:
    Stonington, CT
    Not a question for Dana, as I have already been picking his brain far greater than is polite, to say the least. This post is for readers like me, who never even heard the term HRV. I Google it and got 10,000,000 hits. There are ample descriptions as to how they work, why you should have them, and what they can do for you. I noted the street price can range from under $1000 to the heavens. In particular I watched a professionally made YouTube flick, part 1 and part 2, (total time around 25 minutes) of such a system being installed in a high end New Hampshire home under construction. The flick was not intended for the do it yourselfer but rather aimed at what is involved in a professional installation. Very clear video with a well spoken contractor explaining every step of the installation process. No price of the unit being installed was given, but I would expect it would parallel the overall construction quality of the home being built. The system requires 240 VAC for operation. It also became clear that this new home installation could become far more difficult to install in an existing home.

    I would give my eye teeth up if I was forty years younger, rich, and building a new home. Somehow, I would also expect that very few homes on my block, mostly a mixed assortment of home styles being fairly old, would have a HRV installed.

    http://www.youtube.com/watch?v=WJXBNrkUUYQ
    Last edited: Jan 15, 2014
  19. Dana

    Dana In the trades

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    As long as you have the vent chutes between the insulation and the roof deck, having poly on the interior surface doesn't matter. But going forward, if you fill the ventilation gap and add exterior rigid foam above the roof deck THEN interior-side poly would be a problem, since it would put the roof deck inside a "moisture trap" between the water vapor-impermeable polyethylene, and the barely vapor permeable roofing felt + shingles.

    But it sounds like you have another 20 years before re-roofing to figure that out, eh? ;-)

    There are fairly few central heat pumps using modulating compressors & variable speed air handlers, but a few. The most well known is probably the Carrier Greenspeed, but Daikin has coupled their mini-split compressors to a Goodman variable speed air handler for at least a few models with some success. (Daikin bought Goodman a year or so ago- I expect to see more of these hybrid systems in the near future.)

    My strong suspicion (without actually measuring or calculating the heat load) is that after a round of blower-door & infra-red imaging directed air sealing you would likely be able to drop in a 3-ton Carrier Greenspeed (25VNA036) using your existing ducts, and that it would keep up with both the heating & cooling loads, at roughly half the operating cost of heating with oil or propane. If you click on the "Heating Capacities" tab on THIS WEBTOOL and play around with the different compressor & air handler options at the lower left you'll find that with the bigger air handlers it can deliver a bit over 25,000BTU/hr @ +10F outdoor temps, and over 30,000BTU/hr @ +25F. With a "set and forget" approach to the thermostat it will modulate, keeping up on it's own except for the very coldest nights. With a modest amount of resistance heating using heat strips inside the air handler or auxilliary heaters in the rooms you actually care about (radiant cove heaters are preferable to baseboards, at a comparable price) you would always have some comfortable living space even when it's -5F out (rare, but it happens in Stonington.)
  20. Scup

    Scup New Member

    Messages:
    43
    Location:
    Stonington, CT
    Thanks again Dana, although I was up all last night playing around with the Webtool calculator. I still do not have its proper use down pat. One thing about being an engineer trying to understand an area quite removed from his field of expertise is I am quickly learning HVAC is far more complex than I had ever imagined. I am in way over my head and now know it. To even try to mate my wood furnace with the 25VNA036 is likely folly.

    I believe Carrier always had a good reputation and the 25VNA036 seems like a good starting point, but there is going to have to be a Carrier Dealership somewhere in the picture this coming cooling season. First things first, however, the oil burner has got to go.

    Next, a Carrier dealership in my area has to be selected, the Carrier's dealership finder indicated there are only two: Sears and Bartol. For me that does not seem to be a very big choice due to my having an almost comical but disastrous experience at least forty years ago just trying to purchase a working refrigerator from Sears on one occasion, and then just a few years later another comical experience (this time it had a positive ending) trying to purchase a replacement element for a built-in Sears oven. The store is no longer in its original location, all the old sales and management personnel are probably dead or retired, and likely my concerns are silly; but unless someone convinces me my worries are way off the mark, my recollection of the very distant past is still very clear in my mind.
    Last edited: Jan 17, 2014
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