Move away from oil?

[dietz31684]

I currently have a 30 gallon Therma Flow water heater that is rusting from the bottom, where the bottom of the tank is riveted to the sidewalls. The setup is direct oil fired with a Beckett burner. My plan was simply to swap the tank and move on with life. I started looking around and realized direct fired oil water heaters aren't very common. I called my plumber and he said they don't mess with oil. I called my oil delivery company and they quoted me $2300 (installed) to swap the tank, use the existing burner, and the replacing the the aquastat (new tank apparently changed and old one won't work). While not an insane amount, that isn't exactly cheap for hot water which still has me using a 12 year old burner. The tanks I'm finding online aren't a whole lot cheaper. Maybe $1500-$1800 plus shipping. The current setup does everything we ask of it with lots of hot water on demand.

My other option in a Rheem heatpump model from HD. I live in Pennsylvania so lots of humidity a majority of the year (I currently run a dehumidifier) and I have a fairly large basement which is open. The basement stays around 65 in the winter. I am limited to a 50 gallon model due to the $500 energy company credit that only applies to tanks <55 gal. We have a family of 4. Me, wife and 2 young boys, no plans for more! We do not take long showers (typically in the morning) and bathe the boys in the evening.

I went into home depot ready to buy the Rheem platinum 50 gallon heat pump and the guy working there (I realize HD knowledge isn't the best a lot of the time) basically refused to sell me one. Said that I'll be back there in a week to return it because I'm unhappy with the performance or it'll fail with in a couple of years with all the problems they have had with them. His opinion is the direct opposite of most reviews on their website. He was really pushing me towards the all electric unit, but I have no interest in paying $40 a month to heat water. What he said makes no sense to me. Even if the heat pump isn't as efficient as I hope, I'm still not going to be any worse off than a straight electric tank. After the energy rebate, the initial cost is pretty much a wash.

Natural gas is not an option, unfortunately, or I wouldn't be posting!

Any thoughts or opinions would be appreciated. I've been mulling this over for a couple of weeks now and need to do something soon. Install will be DIY and I have a sump to outlet the condenser so that's no problem. I will have to consolidate a couple spots in my panel with dual breakers, but I've accounted for running a 240v 30amp line.

Thanks -

 

[Sylvan]

Oil is considered toxic and has a very high liability to service or install these appliances

The great thing about oil is its heating value as # 2 oil has 130,000 - 140,000 BTU per gallon and natural gas is 900, 1,200 BTU per CU FT

Oil you can shop around for a great service contract along with competitive fuel prices

Oil you pay for before you use it , gas you pay for as you use

Oil leaks you get a hefty fine

Gas leak you have an explosion

There is always an electric heater no Venting , no fumes and are easier to install and can last for decades

 

[Sponsor]

 

[Phog]

Heat pump hybrid sounds like a perfect option for you now, however if your family bathing habits evolve as your boys age that could change. I'll let the plumbers here speak about the failure rates they see (I'm not a pro), however I'll say that there haven't been many complaints about them on these boards. Which matches the reviews you were seeing and tends to contradict the HD employee you spoke with. What is your home heated by? Is indirect tank off a boiler an option or is it pretty much down to electric vs heat pump hybrid?

 

[Dana]

I'm not a plumber with a lot of direct first hand experience with them, but from all other information sources both the efficiency and reliability of heat pump water heaters has gone WAY up over the past decade.

Recovery time is slow in heat-pump only mode, but if/when faster recovery times are needed putting it "hybrid" mode delivers recovery times comparable to that of a standard electric water heater.

A 50 gallon water heater maintained at 140F storage temperature can support a pair of back-to-back low flow showers of reasonable length. If better showering capacity is needed (now or later), running it in hybrid mode helps, at the cost of higher energy use, but if you have at least 5' of vertical drain downstream of the shower a drainwater heat recovery heat exchanger would improve both "apparent capacity" as well as recovery time, since the water is entering the water heater at room temperature or somewhat higher rather than at ground temperature, and the cold side of the shower mixer is also taking in tempered, preheated water rather than truly cold water, reducing the amount of hot water mix needed to reach a ~105F temp at the shower head.

With a heat pump water heater the apparent capacity increase won't be doubled the way it can be with a gas-burner, but it'll still be well into double-digits as a percentage. A 50 gallon heat pump water heater + heat recovery is likely to have mid-winter apparent capacity of a 65-70 gallon heat pump water heater, not 80. But the recovery time will be much quicker since it's starting with 70F+ water in the bottom of the tank when the outgoing water drops to a tepid 100F rather than 35-40F water.

They're not cheap (figure on $1000 even as a DIY), but they reduce rather than increase the amount of electricity used in a shower, and are an arguably cheaper upgrade than buying an even bigger heat pump water heater. They do nothing for tub-filling capacity/efficiency, since the heat exchange only happens when both the potable water and drain are running at the same time.

 

[DIYorBust]

So what are the options: propane, but you probably don't have a tank. Electric, Heat Pump, indirect, coil and storage system, oil burner(which you already own), perhaps some esoteric types like solar powered. Tankless doesn't seem like a good fit here. I think it's safe to assume that the heating system is oil fired, and probably a high mass type boiler which would not be ideal for an indirect since the boiler would have to warm up to make hot water even in the summer, but it would eliminate an oil burner which would save on maintenance costs. I'd choose the heat pump over the electric, perhaps do some homework on reliability of different models. There's more stuff in it to break, but I think the technology has been around long enough now. An electric/heat pump will have a slower recovery rate, so that's something to factor in depending on your usage.

 

[Dana]

In most local markets propane is as expensive to run as a standard electric water heater, sometimes even more, so the typical choice is electric, heat pump, or oil-fired (either tankless coil, indirect, or standalone.) The heat pump has (by far) the lowest operating cost, but also the slowest recovery rate of any option.

The fact that the heat pump does double-duty as the basement dehumidifier from May through October, and harvests the standby & distribution losses of the heating system to the basement from November through April (lowering the actual heat load on the house) makes the net efficiency even higher than when looking solely at water heating energy use in isolation.

 

[Reach4]

The fact that the heat pump does double-duty as the basement dehumidifier from May through October, and harvests the standby & distribution losses of the heating system to the basement from November through April (lowering the actual heat load on the house) makes the net efficiency even higher than when looking solely at water heating energy use in isolation.

But how does it know when to switch?

If there is any remaining doubt, my post is an attempt at humor.

 

[Dana]

But how does it know when to switch?

Those suckers are a lot smarter than they look (or at least smarter than I look, anyway )

 

[dietz31684]

The oil furnace is forced air, so indirect water heater isn't an option (as far as I understand at least). The furnace is relatively new, I think ~2008? We bought the house 3 years ago. It would be nice to have one less oil burner to service (assuming I ditch the oil WH) and once I run the electric, replacing a tank down the road will be a no brainer. I'm also on a well so my winter water should be a bit warmer to start with.

Judging from the reviews, I agree that it seems like the technology is reliable. They have good warranties so I guess worst case I'll either be swapping parts or a tank.

Thanks for the replies thus far. Sounds like I'm on the right track. I really wish they'd give the energy credit with a 65gallon tank. I'd go that route, but it's hard to leave $500 on the table. My only major concern at this point is whether the water heater can keep up, but I think with electric backup we should be okay. There are just so many variables to consider and don't want to do this twice!

 

[dietz31684]

Also, I just looked at thermostatic mixing valves. Anyone have experience with these? Looks like a way for me to set my water tank to 140 degrees and get ~120 degree water out of the tap extending the "hot water capacity" of one tank. That would give me a bit more capacity in the morning, then it'd have all day to recover (say from 8am until 7pm) on heat pump mode.

 

[Dana]

Keep track of the fuel use on that oil furnace, and use it to measure the heat load of the house at design temperature. With better class heat pumps it's already cost-competitive to heat with a right-sized (and preferably modulating) heat pump than an oil burner, and cold climate heat pumps are getting more efficient year on year. If you already have the heat load numbers in your back pocket you'd be able to spec the replacement equipment pretty quickly and not oversize it. Oversized heating/cooling equipment is more than a mere efficiency/operating cost problem, it's a comfort problem.

When crude was hitting $100/bbl the "pay off" for cold climate heat pumps in operating cost savings was under 5 years. We're one oil price spike away from hitting that price point again (Iran, anyone?)

In the Cleveland area (comparable winter weather to Hershey PA) consultant Nate Adams is often in the position of having to tell folks that their brand new furnace is too big to hit their comfort goals and has to be replaced to get there. So when the opportunity moment arrives, at the point of furnace replacement, seize the day and right-size it. Unfortunately even the smallest burners on oil fired equipment is usually sub-optimally oversized for the heat load, but the silver lining is that it often means the ducts are sufficiently oversized to be able to get there with low static pressure ducted mini-split cassettes, which have more modulation range and are smaller & quieter than full-sized air handler heat pumps (and often cheaper up front.)

 

[Phog]

I don't think you'll have any issues, at least until your kids are in the "I'm showering twice a day" dating/sports/etc phase... Which sounds like a long way away if you're still giving them baths. And yes -- a thermostatic mixing valve will increase the apparent capacity of the tank, as will the drainwater recovery HEX Dana spoke of (in shower mode only). In an increasing number of places tempering/thermo valves are now code.

 

[Dana]

Also, I just looked at thermostatic mixing valves. Anyone have experience with these? Looks like a way for me to set my water tank to 140 degrees and get ~120 degree water out of the tap extending the "hot water capacity" of one tank. That would give me a bit more capacity in the morning, then it'd have all day to recover (say from 8am until 7pm) on heat pump mode.

Thermostatic mixing valves or tempering valves are a code requirement in most places these days. A thermostatic mixing valve is superior to simpler tempering valves, with better flow and bigger adjustment ranges.

 

[dietz31684]

Great, thanks again for the help everyone! You are correct, the kids are 2.5 years and 8 weeks so I'll likely be replacing the tank right around the time my oldest hits teenage years.

 

[DIYorBust]

Great, thanks again for the help everyone! You are correct, the kids are 2.5 years and 8 weeks so I'll likely be replacing the tank right around the time my oldest hits teenage years.

Maybe not if you change the anode!

 

[Dana]

Great, thanks again for the help everyone! You are correct, the kids are 2.5 years and 8 weeks so I'll likely be replacing the tank right around the time my oldest hits teenage years.

You may have to install an occupancy sensor light switch in the bathroom to keep the teenagers from fully depleting the tank, no matter how big the replacement water heater.

At my house the gas burner + drainwater heat recovery unit has sufficient capacity to support a truly endless shower (until the gas company turns off the meter anyway). There was a period of a few years when my kid would have been happy to stay in there for an hour or more without the cue of the occupancy sensor turning off the light. I have it set for 10 minutes, which is plenty for most people.

 

[dietz31684]

I am ordering the mixer valve and parts to install today. I have another question. The HPWH has the hot and cold hookups on the side located a few feet apart from each other. If I'm interpreting the building code correctly, I should have some type of metal pipe connecting the cold water supply to the mixing valve since it's all within 18" of the tank? I'm planning this out with pex and it's getting messy transitioning to corrugated stainless lines all over the place and creating many joints.

I look at install photos online and see many people just ran pex straight to the heater for the hot and cold supply (this is just standard install with no mixing valve). I also see that you're required by code to have 18" of metal (flexible recommended) until you transition to pex. While this may make sense when you have the inlet/outlet on top directly next to a vent for gas/propane/oil, I'm not sure it really matters in the case of electric heaters? I understand 'code', but I'm thinking from a practical standpoint.

Easiest and cleanest option is to screw the mixing valve directly onto the hot output and go all pex from there. I really see no reason to complicate things, other than the fact that an inspector could flag it if we ever sell. I've looked for photos online but had no luck finding any HPWH with mixing valves. And for what it's worth, Rheem installation recommendations taken directly from the instructions have an illustration stating "Flexible Connection recommended (Such as PEX)" connecting directly to the tank.

Opinions? Thanks again -

 

[Reach4]

https://up.codes/codes/pennsylvania says

"Plumbing Code 2015 of Pennsylvania adopts the IPC 2015 without amendments"​

https://codes.iccsafe.org/content/IRC2015/chapter-20-boilers-and-water-heaters
https://codes.iccsafe.org/content/IRC2015/chapter-28-water-heaters

I am not a plumber. It looks to me as if the IPC is permissive on this as long as mfgr instructions are followed. Some codes are not permissive on this. Another code difference is if you can use CPVC for the T+P drain. Some insist on copper or galvanized (still a good use for galvanized). Some permit CPVC. Maybe some allow PEX, for all I know.

If you could route hot water to the dishwasher and washing machine before the cold-water mixer, that would be ideal. If you could mount the mixer or mixers farther from the WH before splitting to the limited-hot water lines, that would be higher performance than having the mixer early and carrying unbranched limited water to the branch.

What kind of PEX are you using? This is not relevant to your question, however.

 

[dietz31684]

Great, thanks for your reply. I plan to use my existing copper line for the T/P drain. I am planning on using Apollo or SharkBite brand (whatever is at HD) 3/4" pex. I'm going to just go straight to PEX, especially this what the MFG calls for. I'm not too worried about the water temperature on the laundry as we never wash with hot, only cold or warm. The dishwasher is a good call though. Thanks for the additional info to chew on.

 

[Reach4]

Great, thanks for your reply. I plan to use my existing copper line for the T/P drain. I am planning on using Apollo or SharkBite brand (whatever is at HD) 3/4" pex. I'm going to just go straight to PEX, especially this what the MFG calls for.

If doing several connections with that PEX, I would use stainless steel clamps rather than SharkBite.

If you did want the stainless flex lines, these would be easy to connect to PEX.

http://falconstainless.com/product/34-pex-barb-connector/ could connect with a stainless clamp.

http://falconstainless.com/product/34″-john-guest-push-to-connect-connector/ has push-connectors like SharkBite, but a different long-standing brand.

However your idea of mounting the pex connector right on the WH should work fine, I think. I got (good deal I thought at the time) some Falcon stainless lines with the expansion pex connections that I use, in case I need to replace my 2003 WH (top connections) some day. I expect 30+ years from a classic atmospheric gas WH, but clearly others have different experience. Incidentally, what is the datecode on your old oil WH? You or a friend might want to check with the Hershey inspectors to see if they have an exception or different interpretation.