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Heat Pumps – The Well-Tempered Future of A/Cs

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Re: Heat Pumps – The Well-Tempered Future of A/Cs

#341

Post by glogla »

gooseyman wrote: post #309

Heat pumps are great, but it’s the dc inverter and advances in compressor efficiency that is really the biggy on energy usage here. Every one of these “heat pumps are the future” articles is so soft on data, and they often fail to explain the basics or a simple “why.” Once we get past the clickbait heat pump articles, we can actually make an impact.

I think the consensus on why heat pumps _should_ be the future is that you can power them with low carbon electricity, as opposed to literally world destroying natural gas.

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#342

Post by baq »

Alupis wrote: post #226
cycrutchfield wrote: post #197

Earlier quoted context omitted.

Induction cooktops heat faster and more evenly than gas

There's many good reasons induction cooktops aren't used in commercial kitchens... and those reasons apply for home-cooks as well.

Woks suck on induction by design and that’s pretty much it. The rest is uniquely US problem of not having 400V installations.

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#343

Post by kbuck »

fireflash38 wrote: post #216
amluto wrote: post #205

Earlier quoted context omitted.

In my local market, if you ask an installer for a heat pump, you get something from Japan or Korea. I’ve never encountered an American unit. (I’m referring to normal air-to-refrigerant-to-air heat pumps. I know of a really weird system that is thoroughly American and an utter pain in the arse to replace because it’s specialized and undocumented. It’s quite loud, too, because it’s single-speed, and that single speed i…

Trane and Carrier are both US based and do heat pumps. They are more expensive than Mitsubishi or Daikin though.

Some (all?) Trane heat pump models are re-branded Mitsubishi units.[0] Not sure about Carrier.

[0]: https://www.metahvac.com/

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#345

Post by Tor3 »

__MatrixMan__ wrote: post #115
jillesvangurp wrote: post #97

Earlier quoted context omitted.

This persistent myth just needs to go away. People use heat pumps all over Scandinavia, including in the arctic circle. They are extremely popular there. They were early adopters of this technology there decades ago. There are two popular varieties: - Ground source heat pumps. Those work pretty much anywhere; just dig below the perma frost and you are good to go on the northern tip of Canada, Alaska, Norway, or where…

I've been on zoom calls with two separate co-workers who are all bundled up because their heat pump can't handle the weather. It doesn't mean that the technology is inadequate in principle--probably their systems have some problem that competent HVAC installers know how to avoid. But its an unfortunate fact that there are places in the US where installers that recommend heat pumps can't be found for 100 miles. It doe…

There are power outages in Norway too - though there are typically years between incidents, and years and years between incidents lasting a day instead of hours (with the exception of certain avalanche-prone areas where this happens much more often than people would like). So my home has a backup system - as do most houses. And that's a wood heater. But my house is so well insulated that it takes a day even in the coldest of winter before I actually need to use it if this happens. Newer houses are also quite much better than mine in this respect.

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#346

Post by bobmaxup »

stephen_g wrote: post #315
simonblack wrote: post #142

Earlier quoted context omitted.

Ditto Australia. We've been using 'reverse-cycle air-conditioners' for heating in Australia for decades. I'm puzzled as to why there is any debate at all on their use for heating. A heat-pump is far more efficient for obtaining heat than direct resistive heating using electricity. Many houses here use no other form of heating at all. And then at the press of a button, we get cooling in summer too. What's not to like?…

Yes. Although I have noticed that some people here in Australia go from the belief that "air conditioners use a lot of electricity" so therefore have the misconception a (resistive) electric heater must be cheaper to use than the reverse cycle AC (heat pump). So there is a bit of an education gap even here where they are quite ubiquitous! I also do want to get a heat pump dryer (it's next on the list after my recentl…

> have the misconception a (resistive) electric heater must be cheaper to use than the reverse cycle AC

You'd think costs would educate. Do people not talk about living expenses much?

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#347

Post by Tor3 »

nightski wrote: post #278
Maxion wrote: post #188

Earlier quoted context omitted.

> It seems to me, there is no future where a heatpump can be the only source of in-home heating then. > > 1) Natural Gas is vastly cheaper in most/all of the US. > > 2) Homes still require an alternative heating source when temperatures drop to low levels (coincidentally when people need heating the most). > ... > I must be missing something here... Yes you are, your natural gas subsidized, i.e. government handout, i…

Heat pumps might work at -40c, but all the efficiency gains are lost and it's going to cost a fortune.

The best one reaches 1:1 when approaching -35C, which means that they're as efficient as resistive heaters. So you save nothing in electricity costs, and if all your days are that cold then the $3000 you invested in the heat pump is wasted (that's how much a quality pump with installation will cost you in the Nordic countries - it seems to be much more expensive in North America, at least that's what the comments appear to indicate).

If you have warmer days now and then then you'll start saving money, and eventually it'll pay for itself. Where I live (cold winters), the cost was covered in only two years.

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#348

Post by vinay_ys »

In India, we have been using "Ductless Air-Source Heat Pumps" aka split AC units with 3,4,5 star energy ratings for decades. The more efficient ones come with dual inverter compressor which allows them to operate at lesser power (for lesser cooling) during long continuous operation periods (like sleeping at night).

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#349

Post by ww520 »

nsxwolf wrote: post #193

When I needed a new air conditioner a couple years ago I was quoted $17,000 for a heat pump. I can only guess at that point whatever energy cost savings it would bring would never be realized within the service life of the system. I went with a $6000 standard replacement AC unit.

Not too far off. I got 5 quotes recently. Most are from $17,500 for $19,000 for a 3.5 ton Mitsubishi heat pump, with an outdoor condenser unit and an indoor fan+coil unit. Permit and inspection from the city add another $1,000.

Re: Heat Pumps – The Well-Tempered Future of A/Cs

#350

Post by baq »

Alupis wrote: post #135
kibwen wrote: post #131

Earlier quoted context omitted.

It's actually difficult to say what the cost would be if everyone switched over. The reason is that natural gas is subsidized, both on the production side (at least in the US, which wants energy security) and on the consumption side (because it's politically unpopular to let people freeze to death). Of course, electricity prices are also affected by subsidies. Figuring out the true operating prices would require some…

It seems to me, there is no future where a heatpump can be the only source of in-home heating then. 1) Natural Gas is vastly cheaper in most/all of the US. 2) Homes still require an alternative heating source when temperatures drop to low levels (coincidentally when people need heating the most). So, even if a heatpump is technically more efficient in terms of emissions, the technology does not solve all of the probl…

You’re talking about the future but only consider the present. You’re one government decision from your calculation to have an opposite result. Estimating probability of any such decision (ban on fracking, tax incentives, etc) is the hard part.
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