That's because your apartment had the cheapest code-minimum electric furnace. Codes are updated and current code-min is almost always more efficient than the prior code minimum.
California Moves To Ban Natural Gas Furnaces / Heaters
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Heat pumps in the comparatively temperate US really are the way to go. I wish I had one.
Not really. You're replacing two systems (Furnace and AC) with one system (Heatpump). The HPWH on the other hand might have some teething pains assuming architects don't go stupid with its placement.
Tell that to my poor sinuses from Dec-Feb in "humid" Atlanta. Our house is so leaky that the interior RH goes down to 30 percent in the winter.
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90% Is a fair constant to use for this. I can see this comparison are valid. Thanks for doing the math!
How do you figure? Electric furnaces all have an efficiency very near 100%, even your refrigerator has an effective heating efficiency near 100% for local heating. More efficient heater fan does not matter, still produces heat the same as the heating elements do, at 100% efficiency.
If the 80% furnace is pulling it's combustion air from inside the house...air leaks from the outside. Assuming you could seal the house up well enough, you'll just starve that furnace of combustion air.
In winter?
Heatpumps have an efficiency typically greater than 200% and as much as 400%.
Yes. I would even use a dehumidifier even in the winter. But someplace colder who knows.
Good point. The only difference would be sizing.
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I live in Northern Virginia and I've never needed a dehumidifier in winter. I needed to run a humidifier back when I lived in a drafty house (built in 1995, go figure) with an 80% furnace.
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Ahhh yes, New York, where they shutdown Indian Point, which was replaced with gas, and then talk about banning gas for normal peopleAs I understand ,NY was/is considering banning NG in new buildings. It has not passed but is/was under consideration. I suspect pushing such a thing will resume after election time.
N.Y. governor backs nation's first statewide gas ban
New York made announcements yesterday on offshore wind, clean energy and a gas ban that could set a national precedent.www.eenews.net
It would be really expensive to get down to 2 ACH50. In any case it's a nonissue for the most part because many of these furnaces are located in vented attics and garages. Attics and garages are "outside" (i.e. exposed to outdoor air 100 percent of the time) so they don't need interior air for oxygen.
Slab-on-grade residential construction almost always have the furnace in the attic or garage. Basements are typically leaky at the sill plate.
Ultimately the issue is leaky duct work in these spaces which release conditioned air into the outdoors causing the house to depressurize and suck in exterior air through the walls, windows, doors, ceilings, floors. Fix the exit/entry pathways and you can reduce the amount of air being sent back outside.
Remember cold air is dry air. Keep the cold air out and you can maintain RH levels.
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Depends on the area. In places where houses have basements---the furnace is usually in the basement, not the attic or the garage. And I've seen a few slab-on-grade houses where they put the furnace under the stairs.
In general it's a bad idea to put furnaces and ductwork in unconditioned spaces.
As far as leaky duct work, current building codes require that ducts be sealed with mastic.
Duct sealing has always been required but installers were sloppy with it. There was a big shift in 2006 towards better air sealing when the Obama administration offered the states a huge chunk of coin if they updated their building codes. Since then many states have updated the codes considerably but you have millions of units which were built to a prior code. Even today states adhere to different standards if they have them.
Codes now have to meet whole house leakage standards which among other things demand an duct system which isn't leaking like a sieve. Better windows, doors, sealing at the top and bottom plates, sill plate, taped WRB (ex, Tyvek, ZIP System) etc all go towards improving occupant comfort by reducing the amount of air which can be pulled into the house.
Ideally the furnace and duct work should be inside the building envelope but it's cheaper for builders to put them in the attic or garage for areas where code allows. I see new million dollar homes with a furnace in the garage of all places.
My home was built under code which pre-dates 2006.
Current code by state
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In northern climates, furnaces normally aren't in attics or garages. They are located in conditioned interior spaces. Typically a basement or what is referred to as the "utility room".
80% combustion units use air from inside the structure. These are (in newer construction) supplied by outside air into the room. Older construction used to depend on the "leaks", but current building codes result in tighter construction.
Because these units draw a lot of outside air in at much colder temps that cannot carry much moisture, the net effect is very low relative humidity indoors during prime heating season. When it is very cold outside (say in Minnesota in the winter) this can result in uncomfortably low interior relative humidity levels. When I lived in Colorado, the very dry air there normally added to this issue, and most houses did use humidification in the winter.
Wasn't there some class-action on 90% furnaces? Perhaps it was 95%. I seem to remember reading something about the condensation rusting out the furnace.
It’s the magic of a working gas that makes a heat pump extract an extra 200% to 300% and maybe 400% under the right conditions. How do you extra heat from thin air when the temp is 30 F? The coils are 5 degrees F and the 30 F heat heats the fluid in the coils. You then compress the gas to a hot temp and exchange the heat to the indoor circulated air. Bingo. Efficiencies way more that 100%.
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