No Heat(er vents) in 2nd Floor of Older Home

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LarryLeveen

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I just moved into an older (1918) 1,250 sq.ft., 1.5 story home in Tacoma, WA. Forced air gas furnace seems to work really well on the main floor (see pix of unit's "badge" at end of message), but there are no heater vents upstairs and we are curious about our options and what might be economical/affordable to provide heat on chilly mornings.

There is a vent coming out of the wall towards the bottom of the stairwell (see pix below). I was curious if that duct might be able to be extended upwards and to serve the two smallish bedrooms upstairs. I realize that ducting is ideally sized/balanced to serve the room areas and this might be less-than-ideal, but it would doubtless be an improvement over what we have now. I don't know if this house lacks firebreaks between the studs, but one never really knows what's in a wall till it's open, do they? Potentially, if needed, the duct could "emerge from the wall" in the stairwell and run upwards in an aesthetic enclosure to serve the upstairs.

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The air return register is fairly adjacent to this stairwell heating vent (see pix below). This seems especially dumb as the second floor has no return. Seems like the upstairs would only be pressurized by the stairwell vent blowing hot air into it. Instead, logic suggests the hot air will instead move to the adjacent air return instead of upstairs. Am I right?

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It is clear that there used to be a door at the base of the stairs that was removed (likely one of the doors in the basement). But without an upstairs air return, I would expect that a door would only help so much — the pressure issue mentioned above would remain and hot air would always follow the path of least resistance and be drawn towards the return. At least, if the stairwell heater duct was extended upstairs, its vents would wind up being at the furthest points away from the air return, making a somewhat decent circuit for heated air to circulate in the rooms and colder air to move towards the return.

Thoughts and advice greatly appreciated. Thanks.

I figured it might be helpful to supply this info:

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Fitter30

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Two story homes if your considering ac heating not so much since most bedrooms run cooler in winter. Mini split system, SpacePac or a regular air handler heat pump.
 

breplum

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FYI, a modern 1,200 s.f. home might have a load demand closer to 35,000 BTU. Your furnace is highly inefficient.
With a lot of work and some asbestos abatement you could get the vent run up higher, like you imagine, but it would not give you much more comfort.
When you replace that furnace, which is less than 75% efficient, you should be able to increase the size of the supply feed to that second floor riser (likely 6" now, so you could make 8" . Plan on getting a properly sized (not 100k BTU!) 96% AFUE furnace with two stage minimum and it will run longer, softer airflow and quieter.
With an old unremodeled house, you will not have good comfort upstairs.
Sorry.
 

jadnashua

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Since the hot air rises, it won't flow directly across to the return, or at least most of it. You could confirm that with a smoking candle wick. Returns are more critical when you have rooms with doors, and the doors are closed, especially if there's a carpet, and the door has little clearance.

That sized duct is pretty small to supply an entire floor of the house. You might improve any performance if you were to add duct fans to boost the airflow.

In many places, a ducted minisplit could add heat and cooling, and may be a prudent choice for the upstairs.
 

Dana

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FYI, a modern 1,200 s.f. home might have a load demand closer to 35,000 BTU.

Huh? 35K? For a NEW house? Is that with the windows open? :)

A modern 1250' house built to IRC 2018 code minimums would usually come in under 15,000 BTU/hr a @ Tacoma's balmy 99% outside design temp of +25F. My 1.5 story 1920s antique is twice that size (2400' of fully above grade fully conditioned space, plus 1600' of insulated but not directly heated basement) and it's heat load is barely more than 35K @ +5F (my local 99% outside design temp.) Before fixing the most egregious air tightness & insulation deficiencies it was pushing 50KBTU/hr @ +5F, but even moving the "before upgrades" picture of the house, moving it to Tacoma would have only yielded about 30-31K design load.

Even without insulation the as-is 99% design heat load of this 1250' house in Tacoma is probably less than 30K, and if there have been any window & insulation upgrades since 1918 it's probably even less than 20K. If there is a heating history on the house that can be estimated fairly accurately by correlating fuel use heat load against local heating degree day data, as explained here.

Per ASHRAE the "right" gas furnace size would be 1.4x the load at the 99% outside design temp, which is enough to cover Polar Vortex disturbance cold snap lows, but small enough to still have a (1/1.4=) 71% duty cycle when it's 25F outside (the 99% design temp in Tacoma.) So rather than intermittent hot blasts followed by the extended chill it's delivering "warm summer breeze" at comparatively lower cfm than with the oversized beast.

So if the real load of this place in it's current where-is-as-is condition is 16,000 BTU/hr (it's probably something like that, assuming storm windows over single-panes, and at least some fluff in the attic & walls) the right sized furnace would have an output of (1.4 x 16k=) 22,400 BTU/hr.

But it's probably better to fix the most obvious deficiencies of the building envelope first, starting with a serious round air-sealing (guided by blower door & IR imaging, if you can.)

Plan on getting a properly sized (not 100k BTU!) 96% AFUE furnace with two stage minimum and it will run longer, softer airflow and quieter.

At WA's low electricity pricing a right sized modulating heat pump with a big turn down ratio (4:1 or higher) might make more sense, even at WA's low gas pricing. If going with a heat pump, limit the oversize factor to about 1.2x, not 1.4x. There are several 1.5 ton - 2.5 ton ducted mini-splits that could fill the bill.

With an old unremodeled house, you will not have good comfort upstairs.
Sorry.

With retrofit air sealing & insulation even antiques can be made reasonably comfortable upstairs without going so far as a major remodeling. But to get there required a master plan and diagnosing it correctly in the first place. Replacing or hacking on the HVAC isn't usually the first step.

Nate Adams runs a company in the Cleveland OH area that focuses on fixing comfort & efficiency issues with older houses, and even wrote a book on the topic. He has some downloadable free chapters and short videos on those topics on his "house whisperer" blog site. It's worth peeking at his Home Comfort 101 and HVAC 1o1 (and HVAC 102) materials as you ponder the plan of attack.
 

LarryLeveen

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Thanks y'all. While I don't understand half the jargon slung around in the replies, the overall message seems clear — start with good foundational data from a thorough home energy audit with blower door and duct testing, inspection, etc. , then make a prioritized plan of attack, likely starting with sealing the envelope, insulating (attic, walls, ducts, pipes), replacing old windows, and only then dealing with the heating (and complete lack of cooling) with efficient non-hella-oversized units that can run with slower blowers more consistently at lower speeds. I'll read the linked guides and will research finding a good energy auditor who will help us make a rational plan. With my ignorance, I'm not in the best position to judge who will actually do a good job in that department, of course — I'll ask for references from other clients — but if y'all have tips there, please let me know. Thx.
 

Dana

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Thanks y'all. While I don't understand half the jargon slung around in the replies, the overall message seems clear — start with good foundational data from a thorough home energy audit with blower door and duct testing, inspection, etc. , then make a prioritized plan of attack, likely starting with sealing the envelope, insulating (attic, walls, ducts, pipes), replacing old windows, and only then dealing with the heating (and complete lack of cooling) with efficient non-hella-oversized units that can run with slower blowers more consistently at lower speeds. I'll read the linked guides and will research finding a good energy auditor who will help us make a rational plan. With my ignorance, I'm not in the best position to judge who will actually do a good job in that department, of course — I'll ask for references from other clients — but if y'all have tips there, please let me know. Thx.

I discovered recently that Nate Adams has a full-chapter reading of the Home Comfort 101 chapter on that video hosting site. Well worth it for the review if you're more of an audio-visual learner rather than a book-reader. His videos are much more instructive and informational than mine. :)

If you have a heating history with gas meter reading dates and quantities from last winter I can run the fuel-use load calculation for you. Even when running a Manual-J or IBR type calculation the fuel use is a good sanity check, since it's a MEASUREMENT that includes all of the standby and distribution losses.
 

LarryLeveen

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I discovered recently that Nate Adams has a full-chapter reading of the Home Comfort 101 chapter on that video hosting site. Well worth it for the review if you're more of an audio-visual learner rather than a book-reader. His videos are much more instructive and informational than mine. :)

If you have a heating history with gas meter reading dates and quantities from last winter I can run the fuel-use load calculation for you. Even when running a Manual-J or IBR type calculation the fuel use is a good sanity check, since it's a MEASUREMENT that includes all of the standby and distribution losses.

That's very kind of you to offer! So, we just moved into our house and the gas company who supplies our gas refused to share the previous owner's data with us (I always thought we had a legal right to that info, but maybe I'm wrong). Fortunately, I just texted the previous owner who — works for the gas company oddly enough — just texted me their usage. Is this what you need?

If you need anything else/additional, please let me know. Thanks and thanks for the links too.

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Dana

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Without exact meter reading dates and amounts it's pretty useless. But now that the heating season has begun even a single month's data can be very useful.

I'd need the ZIP code to find the most-local weather station, the labeled AFUE (or the input & output BTU rates) on the furnace, as well as the thermostat settings. Deep overnight setbacks can skew things quite a bit. (edit: I just looked back through the thread and saw that you have an 80% efficiency 100KBTU furnace, which is simply ridiculous, of course.)

This might be a bit tedious to sit through, but last April Nate Adams ran a webinar (targeted mostly at building efficiency professionals) discussing a case study that also shows his process. His company had fixed the comfort issues in a ~1600-1800 square foot 1960s (?) vintage house that had dramatic temperature differences between the upstairs & downstairs. The homeowner (an engineer) also participated in that discussion. Bear in mind that in his location the 99% outside design temp is about +5F, about 20F cooler than yours.

If you sit through most of it you'll discover that the Manual-J load calculation of the "before upgrades" came in at around 49,000 BTU/hr, but in reality it was measuring closer to 36,000 BTU/hr. After extensive air sealing and reasonably modest improvements to the insulation the real load had dropped to under 30,000 BTU/hr, and the Manual-J was under 40K. They installed a 3 ton heat pump, but Nate commented after reviewing the heat pump performance data that they really could have gotten away with a 2 tonner.

This isn't uncommon, which is why I nearly fell on the floor when it was suggested that your 1200' house needed "only" a 35,000 BTU/hr furnace. Even before fixes it's unlikely that you need anything as big as a 35,000 BTU/hr furnace, but it might if your house is extra leaky. But extra leaky is usually easy to bring down to merely kinda-leaky, without resorting to blower doors & IR imaging (though those tools can help.)

Note, the retrofit insulation upgrades didn't take it anywhere near current code minimums except possibly in the attic. The basement wall insulation added wasn't up to current code, and didn't drop much lower than the above-grade exposure, but it did a pretty good job of air sealing the foundation.

In your house you can probably find and DIY seal most of big holes- you don't need a blower door until you've taken care of the obvious. The biggest less-obvious leak in most houses is the foundation sill & band joists, adding up to more than all the windows & doors combined. Cobwebs near the top of the foundation is one tell-tale sign of a higher than average leak point on the foundation sill &/or band joist.

Even if it has replacement windows it's probably still leaking a ton of air from the window-trim, which may or may not have to be pulled to take care of. In my 1920s house with the original double hungs I was able to seal the casings with caulk without pulling any of the antique casings apart. Since most of those windows are still using sash weights I used retrofit pulley seals around the sash ropes. There was/is still a bit of air leakage at the side jambs (the boards that guide the sash keeping it from swinging into the room), but when pulling them to replace the sash ropes it's possible to seal the seams under the jamb with caulk, and the window gets a lot tighter. All of the extraneous air leakage is usually 2-4x the amount of air leaking around the sashes themselves (which can be retrofit weatherstripped if need be.)

Chimney, duct, plumbing & electrical chases from the basement to the attic can be pretty huge too, often fixable by a diligent DIY-er.

So go crazy on the place with DIY air sealing- any where you feel a draft see if you can figure out where it's coming from and block it. It's almost impossible to make the place "too tight" where active ventilation would be required, until you're on about round three of air sealing aided by blower door, smoke pencils, and IR cameras. Nate's goal is always to make it that tight, but in your more temperate climate you should be able to reach reasonable comfort & control before then.

BTW: I'm originally from western WA, and am VERY familiar with your climate issues. I still have relatives in Kitsap county (the other side of the Tacoma Narrows bridge isn't Asia- it's still WA :) ), and usually visit most summers often taking in some summer skiing between visits with extended family.
 
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