[blahedo]

People are reluctant to install them because they don't work as well as the good old boilers we'd be replacing. I'm not saying they can't, and I'm not saying that there are zero models out there that work. But in practice, a lot of us that have interacted with heat pumps have the specific experience that they get anemic as the temperature goes down and eventually become unable to do much of anything.

I live in the mid-Atlantic (US) climate zone, where it's certainly not as cold as the north but definitely goes well below freezing regularly for several months of the year. The place I've lived for 15 years had a heat pump and a (oil) boiler with radiators, and when it was below 40°F (~5°C) I had to switch to the radiators. It's because it's old, everybody told me, modern heat pumps are better! So last year when both systems needed repairs at the same time, I not-entirely-willingly switched to a brand-new 2024-model heat pump. It absolutely could not keep up when the temperature was freezing until they came back and installed resistive heat strips for low temperature---these seem to be a fancy version of the heating elements in a space heater or a toaster. They do not seem to be particularly efficient. And to the extent that my "heat pump system" does now more or less keep the house adequately warm, if not as comfortable as the radiators always could, it's not solely due to the heat pump, but the other stuff they had to put in because the heat pump couldn't keep up.

My experience is far from unique. Maybe it's that they only install the good ones in farther-north locations! Maybe it's that the good ones are just way more expensive! I'm perfectly prepared to believe the factual statements about the physics and the tech. But if we're talking about perception and "why aren't more people looking to install heat pumps", it's because lots of people have experiences like the above, and that is what the industry needs to work on.

[amarant]

This is such a weird tale to hear. I heat my 2 story 147m2 house in Sweden with a single heat pump and it's downright cosy down to -10C. I have noticed that my office, which is located at the furthest possible place from the heatpump, tends to get a bit chilly when outdoors temperatures fall below -10°c. usually a blanket is enough to keep me toasty, but on the rare occasion that it gets real cold (below about -15°c), I have a fireplace to save the day. That fireplace actually gets used more for the cozyness of a fire than it does for actual need of heating, but it does help on the worst days of Scandinavian winter.

All this to say: if your pump can't handle +5°c, I wonder if you got scammed or if there are other factors at play? Is your house insulated at all? Do you keep your windows open throughout winter? Your experience is so different from mine it's hard to believe we're even talking about the same technology!

[starkparker]

It's the insulation. While it depends on the location and geography, I'd wager that American homes are probably less well insulated than Swedish homes because they didn't have to be.

That contrasts quite a bit with Swedish home standards, which have long been built more air-tight and with considerably better insulated even if they're of comparable age. This has been true for decades, became even more stark in the 1980s, and likely remains very different on the balance: https://www.aceee.org/files/proceedings/1984/data/papers/SS8...

[blahedo]

Responding to this and more generally to everyone mentioning insulation: I'm not saying that insulation is irrelevant, but when I say it fades out at low temps, I mean that if I put my hand over the forced-air duct it feels at best maybe a tiny bit warmer than the ambient air. (Which together with the forced-air circulation makes the room feel even colder, even if the temp is technically going up, but that's more a complaint about forced air, not heat pumps.) Insulation problems would mean I'm running it more and I'm paying more to heat the place than I might with better insulation. But insulation problems aren't what's causing the emitted air to feel cold.

Also, as noted, I'm sure part of it is that they gave me a heat pump that's rated to 5°C or whatever instead of -15. Probably because they expect that everyone around here has a backup heating system, and it doesn't get Sweden-cold (or Chicago-cold, for that matter) in this area. Cool cool, but that just reinforces the message that heat pumps can't hack it and if you're buying a heat pump system you really need to also buy a second system—which may not be entirely true but there's other people on this very thread with a kind of dismissive "everyone knows" attitude regarding backup heating that fundamentally undermines the original message (which was my whole point).

[amarant]

I profoundly disagree with the dismissive people on this thread in all but a few very extreme edge cases. There are heatpumps rated for down to -30°C. If you live somewhere where it gets colder than that, then yes, you'll need a backup system. In all other cases it's just a matter of getting a heatpump that can handle your local climate (I'd argue it's a good idea to get one that can handle at least a couple of degrees below the coldest recorded temperature in your area, just to be safe)

I realise it might sound hollow to say that I don't think you need a backup, given that I myself actually do have a backup in the form of a fireplace. Well, my house is old, even by Swedish standards. A letter I found in a jar under the floor when I was redoing the ground insulation a couple of years back claims the house was built in 1840. I have of course updated the fireplace to be compliant with modern fire safety standards, but the original construction predates heatpumps by some margin. If not for that I probably wouldn't have had a backup. I might have gotten a second pump to help with my chilly office, but that's really more about my house being too big for the pump I have than it is about heatpumps not being able to "hack it".

[eldaisfish]

it isn't insulation.

It depends primarily on your electricity and methane prices. In Ontario, Canada, electricity is cheap enough that heat pumps are cheaper than methane on all but the very coldest days, even if your home insulation is older than 1980 standards.

[ip26]

Some heat pumps bottom out at 35F, some at -15F. It seems to be down to the breed of heat pump, and there isn't much in between.

[throw0101a]

> The place I've lived for 15 years had a heat pump and a (oil) boiler with radiators, and when it was below 40°F (~5°C) I had to switch to the radiators.

When was the heat pump manufactured? Mitsubishi, for one, publishes data were they have 100% heating capacity at -15C, which some models being 100% at -20C and -23C:

* https://www.mitsubishielectric.ca/en/hvac/home-owners/zuba

There's a website for cold climate air-source heat pumps (ccASHPs), that has performance data down to (at least) 5F/-15C:

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

* https://ashp.neep.org/#!/

OEMs can optionally have publish data on "Lowest Cataloged Temperature" if it's below 5F/-15C.

Also: how (air) leaky is your house? how much insulation? For a lot of folks dealing with those two things would be more cost effective than anything.

As it stands, even if you are heating with "cheap" methane (née 'natural') gas, propane, or oil, you're throwing money out the window by letting the heat out in winter. (And the heat in / cold out in the summer.)

[Merad]

I have to agree. I've spent about 2/3s my life in houses with heat pumps and the last 5 years with a gas furnace (the rest being wood heat as a child). Mostly in Western NC and Eastern TN near the mountains, so chilly but not extreme cold.

Heat pumps work, but they aren't nearly as _pleasant_. You can write essays about the efficiency of heat pumps, how lukewarm air works just fine to warm the house, how heat pumps are great _most of the time_ and you can supplement with space heaters or whatever when they fall short... But as long as furnaces are accessible and affordable, an awful lot of people are going to choose to have nice warm heat that is always going to be nice and warm regardless of the outside temperature.

[smnrchrds]

I have never had a heat pump, so I wasn't aware of this shortcoming. Could you please explain a bit more how different it is with heat pump compared to furnace?

[Merad]

The heat pump will always produce air that is warmer than the temp in the house, but as the temp outside drops the temp of the air coming out of the vents also drops. So on a very cold day when the house temp is say 70F, the system might only be putting out air that's 75-80F. The air coming out of the vents doesn't really _feel_ warm and it may take an hour or two to raise the temperature in the house when you wake up or get home in the evening.

In my experience at least with relatively modern heat pumps (roughly 2000 and newer) it doesn't matter that much when outside temps are above freezing. But it quickly starts to become noticeable as temps drop into the 20s.

[smnrchrds]

I see. Thanks for the explanation. So the system is slow to come up to the set temperature. Is it good at keeping the temperature though? After the house temp gets to 70, does it consistently stay at 70, or are there shortcomings in this aspect too?

[lotsofpulp]

That depends on the insulation and how much you open and close the doors and windows.

[estimator7292]

Resistive heat strips are what all electric furnaces use. It's just a bunch of coils of nichrome heating wire. The efficiency of a resistive heater is basically 100%. One Watt of electricity in gives you one watt of heat out.

The mistake people make is assuming a heat pump can do everything by itself anywhere in any climate. If you have cold winters, you need a dedicated furnace to supplement the heat pump.

I say supplement because while an electric furnace is near 100% efficient at turning electricity into heat, a heat pump can be far more than 100% efficient. And that's the crucial detail: a heat pump can give you more heat per Watt than a resistive heater when outside temperatures are warm enough.

[lbotos]

What brand and was it sized for winter load?

Im in NY, 6 heads across 3 floors with 2 heads per outdoor unit. 2500sf covered.

Mitsubishi h2i (i think im on my phone). Get plenty warm in the winter as my sole heat source. I could have gotten smaller outdoor units and had resistive backup but I didn’t want that.

[prlambert]

Yes this is actually the worst – when open minded people get a heat pump for "the right reasons" and then have buyer's remorse. Completely backfires the transition. Do you have a ducted or ductless heat pump? Sounds like ducted, and if so that might be part of it too. The air cools down in the ductwork and if that's not accounted for - i.e. you reuse ductwork that was meant for a furnace – you run into issues like this. And you also need a cold climate heat pump.

(disclosure/transparency I'm the founder of Quilt, a ductless heat pump manufacturer)

[switchbak]

Hi Paul - I'm a big fan of Quilt from Vancouver Island.

It seems to me that you're helping to close the loop on some of the quality concerns that the parent commenter has. Inappropriate sizing/installation and poor product selection seem like common issues from HVAC installers that aren't particularly well versed on heat pumps.

Wishing you continued success, and that hopefully it'll be available in Canada at some point! And also I remember you from the Scala meetup in Vancouver :)

[prlambert]

Also sorry I missed this, not only are we in Canada, we just signed our first partner on Vancouver Island – in Victoria, Pacific Heat Pumps: https://www.pacificheatpumps.ca/

We'll have a partner in Nanaimo very soon as well.

[prlambert]

Thank you! Yes, that is the hope. And what a blast from the past :) Hope you are well

[JeremyPOsborne]

We account for duct losses at Electric Air when sizing. It’s baked into industry standard Manual J sizing calculators and other methods. ManJ isn’t perfect find for this purpose.

In this case, contractor should have advised the heat pump would not keep up and recommended a different solution.

[pfdietz]

When we had our ducted heat pump installed, we also had the ducts in the attic covered with extra insulation, as well as spray foam at the top of the foundation to seal that completely. This all really helped.

[JeremyPOsborne]

Cool!

[pfdietz]

The latter was a surprising (to me) source of heat leakage. As part of the whole effort we had the house examined in detail for heat and air leakage, including using IR imaging and one of those things with a fan that replaces an exterior door to change the internal pressure to find/quantify air leaks.

[maxerickson]

How is the insulation in the house? Poor insulation and an undersized system will be a bad experience regardless of the heat source.

[baggy_trough]

It wasn't a bad experience before, but now it is, because of: new heat pump

[maxerickson]

Well what capacity does each system have?

That they came back and added resistive heating suggests your contractor may not have been too worried about sizing the system correctly in the first place.

[baggy_trough]

Seems like it's harder to correctly size a heat pump system, perhaps because it costs more if right sized, if it's even possible to right size it at all.

[jcalvinowens]

The radiators might make you feel warmer despite not actually making the air in the room warmer: the black body radiation from the big warm radiators affects your perception of warmth in a not insignificant way.

[card_zero]

Seems to me that making people feel warmer is the objective, and making the air warmer is not.

[kevin_thibedeau]

I have a gas furnace and infrared heating panels (glassheat). The panels make you feel warm when you're standing in their path but they are no where near as comfortable as furnace heated air.

[jcalvinowens]

Yep.

[Marsymars]

Basically the idea behind infrared (and far infrared) heaters. I'm really curious about them, but there's no good way to trial them without buying and installing.

[ssuds]

I just wrote a big thread yesterday responding to someone with similar concerns to yours (https://bsky.app/profile/shreyassudhakar.com/post/3m3w3nra2h...). Copying it here if it's helpful to other folks. FWIW, the challenges you are facing seem to be grounded in bad design and application, which happens more than it should and really sucks. We need to move the bar much higher for the contractors installing heat pumps. Here's what I wrote on that thread:

This is why contractor & homeowner education are so so so important to get this energy transition right! I always hate to see reviews like this from folks that have installed a heat pump.

It’s almost always a combo of poorly communicated expectations & installer issues.

A few thoughts…

1) “Air doesn’t come out hot” is a common complaint. It’s by design! You don’t need scalding hot air to have a comfortable space. If you’re targeting a 70 degree setpoint, even 80 degree air will get you there eventually. Heat pumps work best when you let them run - they soak the space with heat.

Your furniture, walls, floors all equalize in temp and radiate heat. A totally different form of comfort than standing in front of a vent that blows hot air at you for 5 minutes and then shuts off!

2) AC doesn’t reduce humidity as well. Unfortunately, this is a classic problem with oversized heat pumps. The key to dehumidification is runtime. A well sized system will run for longer, which will pull the humidity out of the space. If the system is too big, it’ll cycle on and off & not dehumidify.

Your contractor should be do load sizing calculations to determine the size of your heat pump, not using rules of thumb or matching the size of the existing equipment! The very best contractors use performance based load calcs, where they look at your past energy bills to size your new system.

3) Supplemental heat runs a lot - this SUCKS. Electric resistance heat is really expensive to run. It really should be something that comes on for emergencies, if ever. Definitely not regularly.

Many contractors set the temperature where the supplemental heat kicks on way too high. You could be running the heat pump (which is way more efficient) to a much lower temperature, but it’ll switch to expensive aux heat instead. Fortunately, the fix to this is simple - just a thermostat setting.

In other cases, they’ll install a cheaper mild climate heat pump in a truly cold climate. This might save money up front, but it’ll kill you in operating costs when you’re paying 4x as much as you could be in the middle of winter to heat your home. The lowest bid could cost you in the long run!

PS - this homeowner later chimed in that swapping the thermostat helped reduce their electricity bill roughly $30/month! A lot of heat pump issues actually boil down to a poorly configured system. Choosing the right contractor is probably the single most important decision you'll make when you get a heat pump installed.

[doctorhandshake]

This. I had 12 contractors come out for an estimate. I insisted to each that I would only consider estimates accompanied by a Manual J (aka show your work). I got 4 estimates with a manual J, and one of them the vendor said ‘despite that the math says you need a 4 ton outdoor unit, I’m giving you two,’ and refused to budge on that.

I went with a vendor who did the math and sized accordingly and my system works great - great comfort year round and very low energy usage.

[JeremyPOsborne]

If we’re trying to bring down cost the this is the issue with so many contractors coming out. The cost of sales is about 10-15% of the installation in the US. So thats $2-3k in California per heat pump

Try to get an install for $600 like in Japan when you have to pay $2k to find the customer.

Let’s have a lower cost sales process. Review 12 companies online, pick top 3, ask them to come out.

[doctorhandshake]

Yeah in case it wasn’t clear - I wasn’t asking a million vendors to price the job, I was asking them to do a manual J so they could price the job. It took 12 to get 4 to do the manual J. The other 8 came on-site and then refused to do the calcs even though I told them before coming out that it was a prerequisite for me to consider their quote.

I got a variety of explanations for why they weren’t going to do it, most of them along the lines of ‘I’ve been doing this forever - I know what I’m doing,’ but a few disappointingly ‘I don’t know what a manual J is.’ Again, this was AFTER my telling them over the phone that I wouldn’t consider a quote that wasn’t based on the calcs.

[JeremyPOsborne]

Yep, the cost is in the trip is a big factor but sounds like it was their choice to try to sell you. You did the right thing by asking them do the calcs before they came out. Millions of questions are time consuming and costly but better than someone rushing into and pausing mid project with in-decision.

We (I'm cofounder of Electric Air, HVAC contract) have had people pause on day one of install, and that ends up costing the company $10-20K due to delays. Mostly because there isn't something for the team to do for that day or two while we scramble to line up the next customer.

[Marsymars]

I've had a similarly frustrating experience trying to get contractors to redo my gutters.

They seem fine with the gutter part, but once I explain my rain collection system and my requirements around specific downspout sizing and simultaneous overflow, they just seem to have no interest in doing the bit of work required to make it all fit together.

[maxerickson]

Wild that you put it on the customer to reduce the sales cost.

I can see it being reasonable to explain during the initial contact that you want the standardized estimate, once that happens it's not really on the customer if the contractor goes out to chase the business even if they know they aren't going to do it.

[JeremyPOsborne]

You are right! I was unfair. The customer was clear they wanted ManJ calcs.

It's not the customer's problem to reduce cost. The high cost is the customer's problem through even if they are not to blame. And given I have a first hand experience in the cost stack of HVAC company, I would happy to share how a HVAC contractor thinks.

[Marsymars]

> 2) AC doesn’t reduce humidity as well. Unfortunately, this is a classic problem with oversized heat pumps. The key to dehumidification is runtime. A well sized system will run for longer, which will pull the humidity out of the space. If the system is too big, it’ll cycle on and off & not dehumidify.

What if I want more humidity?

(The traditional way with a furnace would be with a bypass humidifier, where ultimately, the energy to vaporize the water comes from whatever the heat source of the furnace is.)

[twothamendment]

I'm in Northwest Montana. My ground source heat pump doesn't struggle until the highs outside are -20F (actual, not wind-chill). I have the backup heat strip, but the breaker is off. I don't know when it would turn on, I just wanted to know it wouldn't without me knowing it.

[glxxyz]

I'm in Canada at a similar latitude with ground source, resistance heating normally kicks in at about -25C (-13F) or so, just a few hours on the coldest nights, doesn't cost much. I could probably leave the breaker off too, I wouldn't mind it a degree or two colder.

[JeremyPOsborne]

Ground source is often the only choice here. While air source can technically work well down to these temperatures, much of the available equipment doesn't suit some homes.

[maxerickson]

Ground source is largely going to maintain capacity independent of the outside temps, so the resistive would turn on when the heat pump isn't keeping up with the heat loss.

[uhfraid]

> “Air doesn’t come out hot” is a common complaint. It’s by design! You don’t need scalding hot air to have a comfortable space.

“It’s a feature, not a bug. Just put on a hoodie and get under the blanket!”

[ericd]

Heat pumps can make the room 90 degrees if I want. But the point is that you can make the room 72 degrees with 80 degree air running constantly rather than 20 minutes of 100 degree air per hour.

[mulmen]

Where in the system did they install the resistive wires? Is that a defroster on the evaporator (outside) or is it inline with the condenser?

[mrguyorama]

Well

Mitsubishi sells heat pumps that produce 14kw of heat output all the way down to 5f at a COP of 2.3.

Resistive heat has a COP of 1, by definition.

Do you know the size of your oil burner? It's likely over 20kw output.

It's not that pumping heat cannot work sufficiently at cold temperatures, it's that you are expecting the electric car rated 100 horsepower to go as fast as the gas car rated at 300 horsepower.

An oil burner sized to the same output as the heat pump also would not keep up.

If you installed two of those Mitsubishi heat pumps (which would require two independent 240v circuits), you would be at 28kw output and would not need resistive heat strips. These units also claim 75% rated capacity at -13f so that would be about 21kw of heat output even when very very cold.

If your resistive heat strips activate at any point other than extreme weather events or emergencies, your "system" is not sized properly. They are a massive waste of power and money.

A big part of the problem is that the contractors who are essentially the point of sale for these systems are just obscenely dumb about them. They will sell you utterly undersized units or sell units that aren't rated for cold, as well as just install things so poorly that they drain condensate into your walls and cause mold issues. They had similar problems with Oil burners, but at least those they tended to upsell bigger systems so their ignorance didn't matter. They seem very bad at doing the planning or design required to actually spec out a system, so you have to be your own engineer.

>and that is what the industry needs to work on.

I don't know how the industry is supposed to force contractors to read their very very clear documentation, or follow the very clear instructions (of boiler manufacturers no less) of "You must measure heat load to accurately size a heat appliance".

[uhfraid]

Spot on.

[WorldMaker]

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 supplement heat somehow in winters (or radiators or what have you), but a "free" boost to 55 degF is still a better starting place than 20 or 40 degF outside temperature.

I don't think latitude is a factor in how efficient a heat pump you can find, I think the type geography under you feet is (probably where "interior" regions probably have more luck than coastal regions), combined with how well regulated or unregulated your area's aquifer generally is (things like nearby wells and industrial water dumping will effect aquifer levels and temperatures). (Maybe not enough heat pump proponents realize that you only have good, cheap heat pumps if you have a powerful EPA and other Water protection groups fighting the good fight in your region.)

[estimator7292]

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.

[cwillu]

Nit: disjoint product classes, but clearly related concepts.

[glxxyz]

The prices when I looked weren't that different- it was about C$30k Canadian for air source and C$40k for ground source (which I went with).

[theluketaylor]

30K would be on the higher end for air source. My install this year was 25k CDN including a lot of duct work.

40K is also on the low end for geothermal. I'm guessing you were able to trench instead of drill?

If you can afford ground source it's by far the best option in cold climates. Steady ground heat means you get the same efficiency all year round. The install can be eye-watering though.

[glxxyz]

Yes horizontal loop, 200 metre trench ~2m deep with 6 pipes at the bottom. Took 3 days for a 20 ton excavator to dig and fill in the trench. Maybe I got lucky with the installer but it wasn't eyewatering. Vertical loops do cost a lot more. Repairing the lawn with turf or professional landscaping would have cost more than the install, so I did it myself with a tractor, some spare topsoil, and a few bags of Costco grass seed.