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Harnessing America's heat pump moment

heatpumped.org

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Re: Harnessing America's heat pump moment

#171

Post by sokoloff »

throw0101a wrote: post #167
sokoloff wrote: post #163

Earlier quoted context omitted.

Typical seasonal average? Sure. At -5°F? Hell no! At +5°F, they rate their own equipment to have a 2.0 CoP. https://mylinkdrive.com/viewPdf?srcUrl=http://s3.amazonaws.c...

Here's a Trane/Mitsubishi unit that has a COP of (at least) 3 at -13F/-25C: * https://ashp.neep.org/#!/product/156605/7/25000/95/7500/0///... An LG unit with 2.4 at -4F/-20C: * https://ashp.neep.org/#!/product/29688/7/25000/95/7500/0///0 Searchable database of cold climate air source heat pumps (ccASHPs): * https://ashp.neep.org/#!/product_list/

Correct (and thanks for the link to that unit).

Though it’s worth noting that that first 2 ton rated unit is putting out 0.5 tons (6k BTU/hr) at that temp and rating.

That’s not going to be particularly helpful for a structure that needed 24k BTU/hr during warmer temps, meaning the owner of the unit is likely mixing in a lot of 1.0 BTUs to meet the heat loss at -13°F.

Re: Harnessing America's heat pump moment

#173

Post by kragen »

crgwbr wrote: post #164
kragen wrote: post #136

Earlier quoted context omitted.

Get solar.

I’ve tried. For it to be at all viable on my property, I’d need to cut down a bunch of trees. I’d rather keep the trees and pay someone else with solar panels.

That makes sense. Is that legal?

Re: Harnessing America's heat pump moment

#174

Post by raddan »

yojo wrote: post #162
sitharus wrote: post #146

Earlier quoted context omitted.

I was shocked when I saw the price of heat pump installation in the US, even with an existing ducted system. There’s no reason a reversible heat pump system should be significantly more expensive than a cooling only one.

It’s bonkers. I bought a pre-charged ductless mini split to DIY. Took my dad and I about four hours to do the install. So call it 8 hours of semi-skilled labor. The unit was $1350, I added a line set cover, pad and feet for another $200, and needed about $200 in electrical equipment - it was a long wire run and code requires installing a disconnect box. The only special tool was a hole saw bit for running the coolant…

I did the same thing and spent slightly less than you did because I did not need the extra linesets, etc. I was also able to install this in a location that few professionals would have tolerated (interior wall). My thinking was that even if the unit died, I would have saved so much on installation that it wouldn’t even matter. It’s a great unit too. Installation costs are kind of a racket.

Re: Harnessing America's heat pump moment

#175

Post by kragen »

srjek wrote: post #158
kragen wrote: post #135

Earlier quoted context omitted.

They can work at lower temperatures, but they do need the auxiliary heat to deice the outside coils.

It's my understanding that nowadays most heat pumps have a defrost cycle where they automatically run in reverse for a bit with some or all fans off

I think that may be how it works, yeah.

Re: Harnessing America's heat pump moment

#176

Post by skywhopper »

corbet wrote: post #91
VWWHFSfQ wrote: post #42

Earlier quoted context omitted.

A heat pump just makes no sense whatsoever for me in my northeast town. The electric bill alone would outpace the old propane bill, not to mention installation. And it won't even work during some of the coldest winter weeks when you _really_ need it to work. Maybe I would consider it if I was in, like, Nevada or somewhere.

My heat pump, in Colorado, kept the house warm at -18°F last winter. Without firing up the backup resistance heating strip. I think it works. (It is more expensive to operate than the natural-gas furnace was, though).

Insulation matters as well and I’m guessing your Colorado house is far newer and better sealed than most New England homes.

Re: Harnessing America's heat pump moment

#177

Post by glxxyz »

danielsju6 wrote: post #148

Maybe I have scar tissue from COVID prices but $20k to install a ductless heat pump vs. a $200 to throw a window A/C in or $700 for a portable heat pump. While I get that these heat pumps are better for the environment and much more efficient it's a last mile issue. The installers charge an arm and a leg and I'm not hurting enough to self install. I'm hoping the window heat pumps that just run off mains will be avail…

It's the opposite for me, much bigger ROI on the heatpump than solar. Rural property, 10 years old, ~3,500 sq ft + basement, in Canada where summer can be above 30C (86F) and winter below -30C (-20F). Electricity costs (Canadian) 7.6 ¢/kWh off-peak and 15.8 ¢/kWh on-peak here.

I spent C$40K (about US$30k) on a ground source aka 'geothermal' heat pump to replace furnace powered by propane tank. I kept propane for on-demand hot water and whole house generator. I have no options for utilities other than electricity.

A couple of years later I spent another C$40k for a 20kW rooftop solar system, with net metering and no battery. Net metering was critical for getting any return at all. A battery is next to useless here- I generate almost all of my solar electricity in May-Oct but use the majority of it in Nov-April. Net metering lets me 'store' excess from summer and use it in winter.

Annual costs:

Before:

    C$8,000+ propane (heating + hot water)
    C$2,500 electricity (cooling + misc)
    $10,500 total
With C$40k investment in geothermal heatpump:

    C$4,500 electricity (heating + cooling + misc)
    C$500 propane (hot water)
    C$5,000 total.
With heatpump and then C$40k investment in rooftop solar:

    C$2,000 electricity (heating + cooling + misc)
    C$500 propane (hot water)
    C$2,500 total.
So I'm seeing about C$8k/yr saving for C$80k investment. The heatpump saved me over $5k a year and the solar about $2,500 a year. The heatpump has pretty much paid for itself after 5 years, the solar will take at least 15 years (unless prices go way up) although should eventually see some return 15-20 years out.

In reality it might have cost even more than that to heat with propane. On the propane furnace we barely heated in winter, burned a lot of firewood to make part of the house livable. I'm trying estimate how much it would cost to heat the house to a comfortable 20C (68F) although the thermostat now with the heatpump is set to 22C (72F) in winter so there's an improvement in comfort as well as the ROI.

Re: Harnessing America's heat pump moment

#178

Post by simmonmt »

mithr wrote: post #26

Electricity costs are a big factor in this, imo. Rates for my northeast town increased by ~25% in 2024 and are going up by another ~10% this year. It's a hard sell to spend a large amount of up-front money (even after rebates, which decreased this year) to convert to a system that will cost you more than you pay today, and may not work as well in cold weather (every heat pump company I talked to suggested keeping my…

Costs are a big thing, sure, but for me it's electrical reliability. For better or worse our heating oil and natural gas supply are both more reliable than our electricity supply. I don't need the heat going out in the dead of winter when some wind storm drops a bunch of branches on power lines.

I'm aware that both my boiler and a natural gas furnace have electric blower motors. It's a lot easier to power them from a generator than it is to have a generator than can power a house worth of heat pumps.

Re: Harnessing America's heat pump moment

#179

Post by cwillu »

estimator7292 wrote: post #67
WorldMaker wrote: post #60

Earlier quoted context omitted.

The strength of your heat pump shouldn't be outside surface temperature, but underground aquifer temperature. Those two temperatures are related but not as directly as they seem. A good aquifer in certain cavernous regions of the US might stay about 55 degF year round, regardless of outside surface temperature. 55 degF is still below what a lot of people want their home to be year round so a heat pump still has to su…

You're talking about geothermal heat pumps which are far less common than air-to-air heat pumps because they are far more expensive. These are entirely disjoint concepts.

Nit: disjoint product classes, but clearly related concepts.
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