Thread: HVAC Heat Pump
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Old 12-28-2025, 03:42 PM   #100 (permalink)
Isaac Zachary
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Location: Gunnison, CO
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Quote:
Originally Posted by Piotrsko View Post
Start with proper search strings: Mitsubishi heat pumps for mobile Home installation. Biggest well known company. GE, also although suspect it's Mitsubishi. rebadged bunch of Korean and vietnamese available for less$$$

-20 &50 room temps just take more time to exchange enrrgy to get to 70. My mild climate rated is still producing, just at way lower BTU on the floor registers, and takes longer to get to 70. @ -20 typical I would have installed the extra heat strips, but it don't normally get that cold here and worst case I fire up the pellet stove. Being all electric it's kinda zero NOX.

Winter electric bill is a whopping $120 @ monthly all electric house, rather un insulated and we have market time pricing
Heat pumps are zero NOx. And it's nice to see one that will work at -20 °F.

But this is "the coldest town in Colorado." I've seen -40 °F quite a few times. Last year it reached -30 °F several days, one day being -36 °F still at 8:00 a.m. If I went the heat pump route I'd first make sure I had a backup heat source. There's no sense in putting in a heat pump unless it's rated for -40 °F.

But let me do some math here.

Last February was the month I used the most natural gas: just over 133 CCF and the bill was $136 total, including overhead, which I think is something like $30. So about a $100 for a very cold month that I use a lot of gas.

If my math is right, that's just over 3,300 kWh of energy, or about 2,500 of kWh energy if we factor in 80% efficiency. Then take the 11.24¢ per killowatt-hour I pay. That would be $281, nearly triple to use resistance heat over gas. So, for there to be any fuel savings, the electric heat pump would have to average about 300% efficient or better.

One thing to keep in mind with all this electric heat stuff is that the trailer has a 100A panel, or 80A useable for continuous loads. A 50,000 BTU/hr electric heater running at 100% would be 14.7 kW or just over 60 amps. Now we couldn't have that running and the 30A drier at the same time, as that would be more than the usuable amperage for continuous loads.
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