Mission Accomplished? Heat pump adoption has a long way to go | Hacker News Reader

Mission Accomplished? Heat pump adoption has a long way to go

heatpumped.org

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Big disclaimer - I work for a heat pump company (Quatt.io).

I suspect that in Europe, there could be a real opening for heat pumps when people want to install aircon - which more and more people do. Many air conditioners (mini and multi-split air to air units) are also heaters, and when I lived in Ireland in a well-insulated new build house we simply used the aircon as our only heater, and it worked well.

Unfortunately, much of Europe uses radiators, and you can't really pump cold water around the house to cool it due to condensation, but even here I think there could be an opportunity with add-on aircons that use the exterior heat pump to vent heat - https://www.quatt.io/quatt-chill for instance.

Anyway, I know the article is about the US, but I thought some perspective might be interesting.

You can if it’s a new construction because mechanical ventilation and heat recuperation keeps humidity low enough to avoid condensation. We do it in our house but the panels are actually huge radiation surfaces installed in the ceiling with a low temperature differential to the temperature in the air. In winter we run the loop at around 25C and in summer at about 17-19C. We do need awnings to control direct sunlight into the house but it works pretty well. With the solar panels and batteries we have we generate about 50% of what we need.

That's really cool! Can I ask roughly where this is? I wonder if it's an area with generally low humidity.

Northern Spain, horrible humidity usually 80-100% max and low of 40-50% max. Company that’s did the installation is a startup https://sunthalpy.com/en/. I was worried humidity would be too high but after the building mass dried out it’s stable around 42-48% humidity no matter what the external humidity is.

Yes, it’s a similar situation in the US! Many folks (especially on the west coast, where summers have historically been mild) don’t have an AC, so big motivation to install a heat pump is to add AC! Unfortunately, plenty of one-way ACs are still being installed; each of those is a missed opportunity where a heat pump could have been put in and decarbonized heating at the same time

I'm in Texas, and my HVAC guys all switched to heat pumps on their own houses a few years ago. The main problem is that most of are on electric AC and gas/propane heat; so, the switch to heat pump usually means throwing out either a perfectly good AC or a perfectly good heater, and installing a heat pump which is, generally about 50% more expensive than either: it's just a lot for a homeowner to swallow. For new builds, the entrenched builders have backlogs of old equipment that they don't want to lose capital on. It's a tough cycle to break.

A shame, really, because they're so nice. And in the US you can even DIY the install! (It cost twice as much to get one in Ireland because I needed an F Gas certified tech).

Is aircon rare on the west coast? I recall basically everywhere having it when I grew up in Sacramento. But I do remember it being less common in San Diego...

Sacramento is not “on the coast”, more of Central Valley, so it does get hot.

Where I live in the “Peninsula” part of Bay Area, we may “want” rather than need A/C maybe 1 week a year. My heating is provided by a 15 year old forced air gas furnace, but I’m in no hurry to install a heatpump because of our ridiculous electrical costs - thanks PG&E.

Our current rates seem to already average at $.5/kwh, probably 5 times more than the rest of the country.

I would wager that adoption of heatpumps is related to cost of electricity vs gas

Nomenclature but I generally think of the west coast on the national scale, but you're correct. I mean, downtown LA is definitely the west coast but it can be much much hotter than Santa Monica, 15 miles away.

But you're right that expensive electricity kills the value proposition.

Is the problem up-front cost on the heat pump (vs pure AC)?

I have a friend remodeling a home in Seattle right now and they’re installing a heat pump in the extension/basement. Seems like a no-brainer given the relatively mild highs and lows. The original house had no AC and radiators of some sort (1920s build, maybe).

Seattle is a great place for a heat pump. Depending on where you are, and your tree cover, most summer days are fine with windows open, but heat waves are icky. Otoh, below freezing is pretty rare, so most of the time, you'll be in the efficiency zone; on the big snow days, it's useful to move snow away from your outside unit to keep it working as well as it can in those conditions. Wall mounted units, common with mini-splits, probably don't have to worry about that.

Utility natural gas is available in some places in the region, but not everywhere... Heating with propane would be pretty expensive, IMHO.

Yeah, they were fine without AC for years. But, with a kid on the way, they wanted more space, and liked their neighborhood enough to remodel vs move. Outside of the remodel, probably wouldn’t make sene to install AC/heat-pump, but once you’re spending hundreds of thousands, it’s a drop in the bucket and making a heatpump made sense.

I'd love AC, but I'd only need it for a couple weeks a year in the bay area.

And I have PG&E so the economics of a heat pump don't pencil out. Gas heating is still cheaper than a heat pump because electricity rates are out of control. (Gas isn't cheap either but still cheaper)

California is doing everything it can to eliminate natural gas heating except for make the alternatives more affordable. PG&E and Socal Edison are basically given a bank check to keep raising rates by the oversight board. (Doesn't help that they are also burning down cities)

Most of the heat pump units in the UK market don’t operate as an AC unit. It’s a hard sell to rip out a working gas central heating system

Yeah, ours don't either (yet) in large part since radiators are more common. Though at least in NL there's a lot of hybrid systems. You keep your gas boiler and attach a heat pump as well. The heat pump handles house heating and the gas boiler still heats domestic hot water.

I have some of (possibly the?) cheapest residential electric power in the US, at 5.58 cents per kWh all-in cost here in Wyoming, 90%+ hydropower.

Absolute lowest cold here each year will be around -30 F / -34 C (there will be several nights in the winter where it gets below -20 F / -29 C), and absolute hottest it will ever be around 85 F / 29 C, but average annual temperature is about 35 F / 2 C. It can snow any month of the year here, with snow on the ground usually between November and mid May.

My house was built in 1968 and I have primarily resistive baseboard heating, with a large Mitsubishi mini-split installed by my home's previous owner mainly for air conditioning purposes in major rooms for a couple of weeks in the summer. I live at 6500 ft / 2000 m altitude, so even on the hottest summer days once the sun goes down it gets quite chilly and can get close to freezing, so it's really just for a few hours in the afternoon for a/c purposes. I otherwise use the heat pumps as baseline heat in the winter.

I'd like to put trust in heat pumps more because they are obviously more efficient (also as seen by my already low power bill), but lack of heat on certain days in the winter has serious implications here for home integrity, and while this might just be this one Mitsubishi model (though they are less than 5 years old), I haven't been left with a good opinion of heat pump design and repairability in general and am not tempted much to explore heat pumps further.

The heat pumps are rated to work down to -5 F / -21 C in the manual, but in practicality it's more like 15 F / -9 C otherwise they just spend a large part of their time defrosting. The models I have don't seem well engineered for reliability or maintenance either, there are important fuses hard-soldered to the main board that are not individually replaceable, and true enough in the middle of winter my HVAC technician and I had to bypass the blown fuses with an automotive fuse we had (same stats) attached with alligator clips, as it would take weeks or months to obtain a new $1500 (!) main circuit board from who knows where. On the other hand, resistive heating usually just works assuming you have power, and I also have two fireplaces as emergency backup if there's no power (though power lines are almost all buried here due to snow/ice anyways).

I really would like to see more emphasis on reliability and repairability rather than, like, SEER, HSPF, or COP ratings or whatever.

See perhaps the "Cold Climate Air Source Heat Pump (ccASHP) Product List and Specifications" from the Northeast Energy Efficiency Partnerships (NEEP):

* https://neep.org/heating-electrification/ccashp-specificatio...

And their product list:

* https://ashp.neep.org/

One of the search criteria is their rated capacity (BTH/h) at 5˚F. A 'proper' installer will figure out the energy you need for the design day in your area:

* https://www.greenbuildingadvisor.com/article/design-temperat...

If you're in a really cold area (IECC Zone 7+), then a dual fuel system could be one option:

* https://www.carrier.com/residential/en/ca/homeowner-resource...

* https://www.lennox.com/residential/buyers-guide/guide-to-hva...

* https://www.trane.com/residential/en/resources/glossary/dual...

Of course before you go spending money on equipment, it's probably a better ROI on better air sealing / draft elimination and insulating. Once you're not leaking (as much) heat then you may need less powerful equipment to keep indoor conditions comfortable.

Our heat pump (~2 years old) doesn't seem to have much trouble with -21C, though we rarely get down that low. With frequent temperatures that cold, a combo unit with natural gas backup for the coldest temperatures likely makes a lot of sense.

I was hoping the Inflation Reduction Act Home Electrification and Application Rebate (HEAR) for buying heat pumps would help, but the money, allocated to the States, seems to be gathering dust where I live.

One of the more salient critiques of the Democrats is that they need to stop taking victory laps when they pass legislation and short-changing the implementation. Part of the loss in this last election was because of how little of what they’d gotten passed had actually made its way into the world (well, that, and a total inability to get a message out, followed by a total unwillingness to say whether what they did was good or not, but at least if they’d actually implemented some of what they’d passed, it’d be harder for people to ignore what they’d done.)

Fair criticism. But structurally the Fed Gov is fairly limited in this regard. Where the Fed can exercise power over the States is to withhold funding that the States need/want in order to push through some change (highway speed limits for example). But you can't force States to spend money on something they don't already have, so there isn't much leverage other than making the funding available and hoping that the States will take it the rest of the way.

The EV station rollout is similar -- Congress allocated a bunch of money, but they can't force States to come up with plans and the States have taken a long time to do so (of course these things take time anyway). And now the money is being taken away -- missed opportunity. But not sure what else Congress could have done?

The highway system must have been done somehow. I don't know the details but there has to be lots of ways to ensure these things get done. Maybe it's lack of political will or maybe it's loss of people who know how to get these things done.

Right. But the highway system was something that greatly benefited the States themselves as it provided them with new roads stimulating their local economy and creating a great number of jobs (to build the roads). But the States weren't forced to do so, and it took 35 years (I didn't know that until I looked it up[0]). Heat pumps benefit consumers, and climate change, but there's probably less incentive for States to push the program, especially if they don't really care about climate change anyway.

[0] https://en.wikipedia.org/wiki/Interstate_Highway_System

Yeah, these things are true, but I think that needs to be baked into the calculus on these bills: getting them passed isn't even half the battle - if you don't have an answer for how to get the money down to the ground, the law's just an interesting piece of paper.

On the one hand, fixing the dysfunction at the state level is, you're right, outside the purview of the Feds - although when the Democratic governor and Democratic legislature of a state and the Democratic mayors and city councils of the city are where the money's stopped, I think that's still a rock you can throw at the Democratic party.

I also think there's still a belief (fading, thank god) among the Democrats that if they do the right thing and the Republicans stymie them, they'll get credit and the Republicans will lose face (call this the Obama theory of polite governance). At the end of the day, passing bills that get blocked by the opposition doesn't show people your virtues, it shows them your inability to get things done.

And now it will most likely be clawed back.

Not just clawed back, but spitefully used to encourage people to burn coal to heat their houses. Residential rolling coal.

https://en.wikipedia.org/wiki/Rolling_coal

The HVAC trade at least in the US is interesting. I have dealt with quite a few companies, and collected a range of quotes with wild variations in pricing for essentially what is the same exact system. In my anecdotal experience the residential HVAC industry is full of scams. Maybe it's just poorly run companies that need to break even is the reason for such gouging. A quote of 12,000 USD for a 2 head minisplit system installed from one company, was 5,800 USD from another. And a Mr. Cool DIY kit could be shipped to my house for 3,000.

I know there is some skill in braising the lines and evacuating the system, weighing the charge, etc... and the industry is gatekept with certifications, permitting and environmental compliance, but I image most any handyperson can handle an install. Especially with the pre-charged lines that are available in many kits.

I've had about a dozen residential HVAC technicians do some kind of work over the past year, due to a warranty claim and they had to visit 6 times, never could troubleshoot the problem, and in the end just installed an entirely new outdoor unit. The first technician claimed the problem was a 'dirty blower' and quoted $1,200 for them to come clean the blower fins on my condensers. The second one said it was definitely a board. Then it was the board on the other end. Then it was the same board they already replaced once. They were all wrong. But their troubleshooting was done over the phone with the manufacturer. I was civil and patient with them, but it was hard to watch. I think the residential HVAC industry is the biggest problem with US adoption... The rest of the world seems to be handling it fine.

Competency indeed seems like one of the larger challenges for them in the US, especially during the sizing phase. When I had some mini-splits installed, the amount of bad information and outright lying even from established, top rated contractors was staggering. When we finally found someone that wasn’t completely stupid and quoting “fuck you” prices, they completely oversized the units. In the winter, they are reliably toasty warm even below zero, and in the summer they cool the rooms quickly… too quickly. Like, almost instantly. The result is a terrible increase in humidity, because they don’t run long enough to pull water out of the air. If I run them in dehumidification mode, it turns the room into a meat locker. So, I have to run a regular floor dehumidifier in the summer, much to my chagrin. When I look at the other quotes I got, they were all similarly over provisioned. Very frustrating.

I found anecdotally that it was fairly difficult to get a heat pump when I replaced my air conditioner last year. Several reputable and carefully vetted companies suggested that retrofitiing it into a midwestern house to replace an air conditioning, because it only worked efficiently on a certain temperature band. I’m not sure why they do it, but replacing my existing system with a heat pump was heavily discouraged by the vendors in my area. We have boiler radiant heat in our older home not forced air.

On this topic I've been wondering why are the air-air heatpumps significantly cheaper than air-water units?

As far as I could tell, there's not that much of a difference (different heat-exchanger, circulation pump instead of a fan, maybe a three way valve for hot water)- but I have hard time seeing how they contribute to the price difference of several thousand EUR.

There are also quite a few conversion projects (where an air-air unit is converted to air-water), so I'm wondering if it really comes down to just higher demand for air-air?

One thing I found out that's a bit infuriating is committee the the sets national code standards has effectively banned R290 (propane) monoblock heat pumps. No residential indoor or outdoor heat pumps with more than 144 grams of propane. You can have a 20lb tank of propane on the BBQ you store in your garage in winter. Trust us this has nothing to do with the representatives of the companies that manufacture refrigerant on the committee.

It's infuriating because a R290 monoblock air to water heat pump is something you could install yourself. And R290 is really cheap and environmentally friendly.

I think we'll see a lot larger scale adoption of heat pumps once they are re-engineered for dealing with 15F average winters (where heat pumps break even vs furnaces) that also go down to -25F for a week (where heat pumps use more energy or fail). But it's good to see small progress in using them in places where it only gets cold rarely and briefly.

Not being able to handle the full range of average and peak(valley?) temps means a lot more complexity that prevents adoption.

We’re already pretty much there!

https://www.energy.gov/eere/buildings/articles/doe-efforts-s...

“Bosch, Carrier, Daikin, Johnson Controls, Lennox, Midea, Rheem, and Trane Technologies participated in the challenge. They successfully completed prototype testing at Oak Ridge National Laboratory and other facilities in 2022 and 2023, with some units operating at temperatures as low as –15°F (–26°C) while still meeting efficiency requirements. The companies then moved products into field testing in 23 residential sites located across 10 U.S. states and 2 Canadian provinces. In partnership with Pacific Northwest National Laboratory, each site gathered a full year of data. U.S. testing sites were in the Northeast, Midwest, and Mountain regions.

In the field, the residential CCHPs reliably provided heat with little assistance from auxiliary elements, even during the coldest winter periods.”

What hurts adoption here in NL from what I hear (from installers so grain of salt etc etc) is that there aren’t enough people to do installs and then later maintenance.

Having looked at getting a heat pump set up in our house (built in 1902) is that even with the extra insulation we put in, the energy needs of a heat pump are huge which means more electricity is needed and what with congestion happening locally is getting to be a problem to supply all houses with enough oomph to run heat pumps, electric stoves and charging EV’s.

Even with people having solar installations this remains a problem because we’ve had almost three consecutive weeks with heavy cloud cover and fog as well as hardly any wind. So renewable power generation was down across the board.

Fact of the matter is, we adopted many energy hungry solutions without providing the necessary capacity up front.

I worked at a startup (Jedlix) where we built a platform to optimise EV charging specifically to deal with these problems (demand shifting) but there are so many hurdles to get this rolled out at a large enough scale to matter.

Car OEMs don’t provide the necessary APIs, (local)grid companies won’t provide usage data necessary to steer on so billing/compensation becomes impossible removing the incentive for consumers.

It seems so obvious that this would solve a real problem but even though the technology exists it’s not going anywhere. Maddening

Also in NL and I work for a heat pump company - I don't know the specifics but for as long as I've worked here we've never not been hiring heat pump techs. (https://quatt.recruitee.com/)

I actually am hoping that better grid coördination could help a lot with the problem you describe, there's a few companies in the space but I can't think of big ones in NL. In the UK you have Octopus Energy which has effectively made a (virtual) power plant by managing individual assets.

Hey to all you NL people (we're in Den Haag) - I've been researching solar water heaters and they look really promising? I've read they even work in winter. Is that wishful thinking in a country like NL?

They work in winter provided there is enough sun.

If there’s no sun you’re looking at a different energy source which typically means electricity so you’re back to the demand problem when the weather is poor regarding renewable power.

I can't really comment except that when I asked our installers about it they had the perception that solar water heating was "an 80's and 90's thing". I don't know much about it beyond that.

I guess you could look up the insolation values and do the math on how much water you use and how hot it needs to be.

Jedlix had been acquired by Octopus in fact and specifically for the virtual power plant tech + EV integration.

What’s more challenging is that when it comes to EV charging in cities not a lot of people actually have their own charging station and need to use public ones. That means they’re in use all the time and “throttling” them causes availability problems.

One of the challenges would be to get people to charge their cars during the day when there usually is a power surplus (especially with solar when the weather is decent) but that’s a behavioural change that takes time.

Another problem in a densely populated country like the Netherlands is noise pollution by heat pumps. One of my friends has been in a conflict with his neighbour over just that which has cost a lot of time and money and probably can not really be solved entirely as the law is written, the distances between houses and the noise signatures of heat pumps and whatever sound-dampening enclosure they are stuffed in don't meet. This is not a problem where I live (Sweden) since we have way more space and build less densely than in the Netherlands.

This definitely also is a problem for the reasons you point out: density.

Have heard a few stories about it and it’s also a quite common topic in HOA meetings when someone wants to place an aircon unit.

Is air-con just that rare? A heat-pump isn’t all that much complicated than a ducted air-con. Here in the US, most HVAC service companies can/will service all types (pure AC, heat pumps, various furnaces, etc).

Mean daily maximum in July and August in Utrecht is 23C/73F (compare to 30C/85F in Chicago and NYC). The Netherlands is further north and a lot more moderated by ocean temperatures - it's kind of like SF in that regard except the entire country has a similar climate so AC is not a cultural expectation.

> Mean daily maximum in July and August in Utrecht is 23C/73F […]

Which is why heat waves/domes can be so lethal in Europe: people/infrastructure are not prepared for them.

* https://climate.copernicus.eu/heatwaves-brief-introduction

Same problem in Vancouver, Canada: it's a Marine climate, so when heat hits, folks aren't prepared for it.

In the UK at least, domestic air conditioning is extremely rare. Less than 5% of homes (I'm surprised it's even that high, although I am up North).

Oh wow, that’s lower than I would have expected. Totally makes sense in the north and Scotland.

How are most homes in England heated? Gas furnace + radiators?

Yup. Gas boiler central heating with radiators.

Air con is fairly rare here in NL although you do see more units popping up so it may be getting more popular.

These conditions are pretty common too (winter anticyclone).

We installed a heat pump last year (2024) when we decided our condensing gas furnace wasn't going to last that much longer. Various incentives paid for about 1/3rd of the cost, and we had insulation upgrades at the same time as well as replacement of an electric water heater by a heat pump water heater. Overall, we've been very pleased with the level of comfort and the economics.

This is near Ithaca NY, where the coldest month (January) has an average low of 18 F.

I'm definitely interested in heat pumps, but we also live up north - 12F average in January. Does it hold up well during polar vortexes, when you are below 0 for a few days?

We haven't experienced that yet. I think the lowest temperature we experienced since it was installed was -4 F one night. We didn't notice any problems.

The only issue I've seen is the large buildup of ice below the outside unit. The unit is elevated on legs for just this reason so it hasn't affected its operation. The ice is formed when the outside unit goes through its defrost cycle in cold weather; water dripping off freezes when it hits the ground.

I’m in DC and my childhood home and both homes I’ve owned have had heatpumps.

They all have back-up electric heat elements that kick on when the heat pump can’t keep up. In our mid-70s build home (mediocre insulation and windows), that happens somewhere in around 15F. Basically a few nights/month in Jan and Feb. I can see the bump in electric bill when we have an unusually cold winter.

But, overall it’s not a bad system. Most of the time, it works fine. The one downside (vs radiant heat) is it can feel drafty. But that’s going to be true of any forced-air heat.

Anyway, sounds like you’re right on the edge of where a heat pump might be suitable, so you’ll need to talk to a specialist (or at least somebody else who’s used one locally). They’ve come a long way in efficiency and if it’s a new home, the better insulation will help a bunch too.

For those 1-2 days a year when a heatpump cant keep up with the cold, its fine to have a plug-in heater.

Heat pump water heater - is that ducting the waste heat outside somehow? I’ve thought about them but not sure I want something dumping extra heat into my basement when it’s 100* outside here in DC metro.

No, it extracts heat from the air in the basement. It cools the surroundings (assuming one is using the hot water, not allowing all the heat there to eventually diffuse out through the insulation, but a resistive water heat faces that same issue without having caused any cooling first.)

Oh, lol, I had it backwards.

But in winter, when I’m using more hot water, the heater is cooling a house I’m desperately trying to keep warm? Not sure that’s any better. Is the amount of cooling noticeable? We’re in a small (by US standards), mid-70s home - it’s already next to impossible to keep the basement warm enough to use in January.

Did you have a gas water heater and furnace? How much is your electricity per kwh?

We had a gas furnace but an electric water heater. Last month we paid $0.196/kWh (including distribution charges, supply charges, taxes, and various minor fees.) Better than CA, worse than TX. Average power use over January was a shade over 4 kW.

Lowest temperature so far this winter has been -21°F and my Haier Arctic heat pumps kept going (although I concede it was only lower than -15°F for a few hours in the early morning while I was asleep). As for costs, they're pretty much on par with oil currently but my house isn't yet adequately insulated.

I suspect once I have sufficient insulation and air sealing, and condensing gas hydronic heat for when the exterior temperature drops below 5°F (COP 2.0) the overall system will be very cost effective month to month. Although the upfront cost is nontrivial, so it's a payback period measured in decades.

I also augment with a wood burning stove.

For new construction that's properly air sealed and insulated, heat pumps with resistive baseboard backup would probably be sufficient.

Heat pumps are used extensively in Scandinavia, including up in the polar circle. These are usually ground source heat pumps, which is the essentially the same pump technology but connected to an in-ground loop instead of taking heat from outside air.

Nowadays the air con uses the same heat pump to extract heat from the house and pump it into the ground, which not only chills the house but also helps a little recharging the ground source.

Ground source heat pumps install cost is very high when used in cold areas because of the frost depth caused excavation costs; significantly higher than the cost of the heat pump unit and parts themselves. It can be good if that disproportional initial cost is paid. But it's not the same class of purchase. This cost is reflected in the lack of demand and so lack of (solvent) installers.

If the big initial cost is rolled into home construction it would be less daunting and more normal. So I expect newer homes to adopt heat pumps in cold areas but with little adoption in existing homes.

I read somewhere that you can just drill a well and install a big coil?

News to me. But probably similarly expensive once the environmental regulations for wells, etc, and it's excavation are considered. And even fewer installers who are qualified to do it.

You are making this up as you go :)

Yes they are often installed in bores into bedrock.

All those pesky Scandinavians must be doing it because it makes economic sense.

Step back and think that if you don’t know the details then all the excuses you can imagine are probably misleading or wrong.

I see you just skipped to responding to the end of the comment chain instead of reading it. Common mistake. Here is what you missed,

>If the big initial cost is rolled into home construction it would be less daunting and more normal. So I expect newer homes to adopt heat pumps in cold areas but with little adoption in existing homes.

In Scandinavia heat pumps are often replacing wood burners in existing houses. Source: I live there

Yes, ground sourced is an excellent option, and I would also consider it for new construction in my area (Northern New England, US). The problem is finding installers that can do it.

I had a large house that was heated by electric and wood and replaced them with a ground source heat pump with a loop zigzagging under my lawn. Relatively expensive to install but paid for itself in 5 years.

YMMV. Good luck, hope it works out for you too :)

> Lowest temperature so far this winter has been -21°F and my Haier Arctic heat pumps kept going […]

Crikey:

> For zones with exceptionally harsh winters, the Arctic mini split AC with heat pump ensures you stay warm even when temps get down to -31 degrees F.

* https://www.haierappliances.com/ductless/arctic-next-gen-ser...

-35˚C.

For exact reason I want heat pump (i mean these ones with 60C temperature output), but my range starts from -5C (23F), where efficiency starts to drop. As for connecting to house heating system with furnace using mini-split is just few pipes and one or two valve away. Is not hard to have big note, reminding following: "light furnace - close valve a, use heat-pump open valve a and close valve b"

Main problem is price... The air-water heat pump which looks match my house something from 4000-4500€ and I living in small house. Yes there is government assistance, but main requirement is to remove (to wall up) chimney and remove burning stove... which during cold winter will rake costs to insane numbers.

This is only for air source pumps, right? My furnace will probably outlive me so this is a more theoretical discussion but my plan has been to get a ground source pump if it ever breaks.

The physics don't change but the ground never goes to -25F. So yes, after paying for digging (unless you have a deep pond), well designed geothermal remains efficient regardless of season. It is seen as the most efficient option, especial in more extreme environments.

Heat pumps are quite prevalent here in Norway, where we regularly see -5F or lower.

I got one and while this winter has been mild, not much below 15F so far, last winter we had couple of weeks below -5F and we had a nice 73F indoor without issues.

And to be frank I don't care if it's less efficient couple of weeks during winter if it's more efficient the remaining 50 weeks.

Bonus points is that it can keep us cool during summer, unlike a furnace or heating panels.

How much is your electricity per kWh?

Usually during winter around 10-20 cent/kWh, though can go several times higher depending on weather.

Nice! 28 cent here in the UK!

Plus 23 EUR/mo fixed charge

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