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Nine US states are teaming up to accelerate the adoption of heat pumps

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Re: Nine US states are teaming up to accelerate the adoption of heat pumps

#501

Post by Reason077 »

jhallenworld wrote: post #497
mdasen wrote: post #174

One of the big problems with heat pumps in New England is that our electricity costs 1.7x the US average ( https://www.eia.gov/electricity/monthly/epm_table_grapher.ph... ). If you're in the South, a heat pump makes perfect sense. You're going to want AC anyway and it'll be way more efficient and save a ton of money when you want heat. In most of the country, even if it gets cold your electricity prices are still a t…

It's a big problem for electric cars too... Here are the current prices per kwh for me in MA: Electricity = $.26 / kwh Propane (LPG) = .134 / kwh Heating oil = .095 / kwh Gasoline = .091 / kwh Natural Gas = .082 / kwh

You still need to account for efficiency of the various fuels when working out which one is cheapest.

An electric vehicle is on the order of 5X more efficient than a gasoline vehicle per kWh (that is, an EV that will go 5 km on 1 kWh of electricity would be lucky to get 1 km per kWh if it were running on gasoline).

So in this case, it's still cheaper to operate an EV than a gasoline vehicle in MA, even if electricity costs more per kWh.

Re: Nine US states are teaming up to accelerate the adoption of heat pumps

#502

Post by smeej »

theteapot wrote: post #268
mdasen wrote: post #174

One of the big problems with heat pumps in New England is that our electricity costs 1.7x the US average ( https://www.eia.gov/electricity/monthly/epm_table_grapher.ph... ). If you're in the South, a heat pump makes perfect sense. You're going to want AC anyway and it'll be way more efficient and save a ton of money when you want heat. In most of the country, even if it gets cold your electricity prices are still a t…

> Heat pumps do work into freezing New England temperatures, but they're a bit less efficient as it gets to zero fahrenheit. What's the temperature in the ground? Did you look at a ground source heat pump ( https://en.wikipedia.org/wiki/Ground_source_heat_pump )

There's a reason NH is called "The Granite State."

Planning to put things underground in at least that part of New England is not likely to go very well. It can be done (plenty of places have septic tanks, for example), but it's not easy.

Re: Nine US states are teaming up to accelerate the adoption of heat pumps

#503

Post by Scoundreller »

fnbr wrote: post #350
xutopia wrote: post #303

Earlier quoted context omitted.

I'm in Canada and we have heat pumps with secondary heat sources for when it gets really cold. Mine is with gas.

Yup, me too. And with my Nest thermostat, I can manually configure the crossover point. I did so at the economic balance point (where the heat pump is cheaper than my gas furnace).

Is there any capability in having a "smart" economic balance point? IE: Accounts for time of day/market pricing of kwh? I guess there needs to be occasional reprogramming of gas prices?

Re: Nine US states are teaming up to accelerate the adoption of heat pumps

#504

Post by jlawrence6809 »

zbrozek wrote: post #42
jacobolus wrote: post #26

Earlier quoted context omitted.

Can you explain why this is a big issue?

The simplest devices are on or off. If they are grossly oversized they cycle a lot and make homes less comfortable by pushing a huge volume of hot or cold air briefly. Variable speed compressors are better, but blowers may not also be variable speed. So you'll get better efficiency but may still suffer a feeling of draftiness. A properly sized variable speed unit will operate within some optimal band of efficiency an…

When I was shopping for a mini split recently all the models I could find seemed to be variable speed compressor and blowers, unless I was reading something wrong. So maybe this isn't an issue anymore? I oversized mine but wish I went even bigger after a cold snap we just had in the pnw this last winter.

Re: Nine US states are teaming up to accelerate the adoption of heat pumps

#505

Post by scruple »

michaelt wrote: post #496
bagels wrote: post #214

Earlier quoted context omitted.

Right, the heat pump will reduce energy use to maybe 1/3 of a gas furnace, but natural gas is something like 6x cheaper for the same amount of energy, so it is an expensive folly. If California is serious about this, they need to reign in the utilities to reduce prices and or stop the attacks on solar installation.

> stop the attacks on solar installation I don't know if the experience of a Brit with a roof covered in solar panels applies in California, but: during months when you want to run the heat pump, your solar won't be producing shit.

In Orange county, CA, we generated 16.6kWh today, on a 5.6kWh system, and it's been partially sunny with some sporadic rain storms.

Re: Nine US states are teaming up to accelerate the adoption of heat pumps

#506

Post by Garypaul »

Aloha wrote: post #431
stephen_g wrote: post #401

Earlier quoted context omitted.

What kind of system do you have that is only giving you (if I’ve converted the those very confusing units correctly) a COP of 2.2 at 10° C? That’s really very poor… There are air-to-water units that can achieve COP > 4 at 0° C, and even a good air-to-air should still be over COP 3… I’d expect to see a COP like that at -15° C or below on a modern unit…

Should have been 60,000 BTU, I read the wrong column

[flagged]

Re: Nine US states are teaming up to accelerate the adoption of heat pumps

#507

Post by switchbak »

vundercind wrote: post #2

> Death is coming for the old-school gas furnace—and its killer is the humble heat pump. Uh, you still need a furnace (though it could be electric) if you live somewhere that ever really gets cold, right? [edit] I mean, seeing it presented as a furnace replacement is weird to me. I’ve always seen it sold as an air conditioner replacement that also happens to heat (with weird characteristics that often confuse people—…

They make ones that handle the cold quite well, but in my mind dual-fuel is where it's at, especially if you're doing a retrofit. Unfortunately there does seem to be a desire (even with the rebate systems) to kill the old furnaces.

Re: Nine US states are teaming up to accelerate the adoption of heat pumps

#508

Post by jhallenworld »

Reason077 wrote: post #501
jhallenworld wrote: post #497

Earlier quoted context omitted.

It's a big problem for electric cars too... Here are the current prices per kwh for me in MA: Electricity = $.26 / kwh Propane (LPG) = .134 / kwh Heating oil = .095 / kwh Gasoline = .091 / kwh Natural Gas = .082 / kwh

You still need to account for efficiency of the various fuels when working out which one is cheapest. An electric vehicle is on the order of 5X more efficient than a gasoline vehicle per kWh (that is, an EV that will go 5 km on 1 kWh of electricity would be lucky to get 1 km per kWh if it were running on gasoline). So in this case, it's still cheaper to operate an EV than a gasoline vehicle in MA, even if electricity…

It's more like 2.5 to 3x for good ICE cars (they are around 30% efficient- I think it's been going up over the years, in the past I assumed 15%):

https://en.wikipedia.org/wiki/Engine_efficiency#:~:text=in%2....

But anyway, the big issue is for electric cars fast chargers, more like $.48 / kwh..

For carbon emissions, the WTW (Well to wheel) efficiency is more important- they are about the same unfortunately (we need more solar):

https://ui.adsabs.harvard.edu/abs/2020SJRUE..24..669A/abstra....

Re: Nine US states are teaming up to accelerate the adoption of heat pumps

#509

Post by icehawk »

torpid wrote: post #367

I live in an old furniture factory converted into lofts. LEED certified of course, with mini splits instead of forced air in each unit. This is in the midwest. For the past 11 years, every season it's failed to maintain minimum temperature of 68 degrees when it hits below 5 degrees outside, or maintain cooling in the summer. Another adjacent building built 2 years after this one with the exact same setup, same story.…

I've had the same issue with an apartment complex, the AC it could never properly maintain The issue was that builders didn't properly size the AC unit for the amount of heat it needed to reject in a 5th floor apartment when it was 100F outside.

> or maintain cooling in the summer

Here's the key phrase.

This isn't an issue with a heat pump. They just undersized the unit.

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