And for the record, every single natural gas water heater is connected to 120V power for the ignition circuit.
My Rheem hybrid 220v heat pump water heater only has a 500w compressor but puts 1500-2000 watts of heat into the water pulling it from the hot garage.
I have the choice to run it in high demand mode which will run both the heat pump and electric 4500w element for around 6kw of heat into the water if I need fast recovery.
kwatts_effective [kJ/s] * heating_time_minutes [min] * 60 [s/min] * COP = 4.184 [kJ/kg/K] * (T₁-T₀) [K] * gallon_capacity [gal] * 3.785 [L/gal] * 1 [kg/L]
6.6 kW, for... COP 4, T₁-T₀ = 30 [K] (lower value for warm climate), allowable 30 minute heating time, 50 gallon capacity. A cold climate could double that power requirement, or alternatively double the heating time.
Mine isn't. During a long power outage, I still had hot water.
I was a bit surprised the water heater was working since I was pretty sure it had an electronic control system. So I went and looked, and sure enough, it was electronic, and somehow the LED was flashing blue like normal!
It turns out the electronics are powered by a thermopile which is heated by the pilot light.
This is incorrect. Multiple homes I've lived in had no electric to the water heater, including my current.
With a standing pilot a thermopile is used to generate the tiny bit of electric required for the control.
But you might also be comparing multi-stage variable load DC heat pumps with single stage air conditioners and not an actually equivalent air conditioner.
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 existing gas heating in place and automatically switching to it when it gets cold enough).
I was also told that the electrical grid in my area is having difficulty keeping up with the push towards heat pumps, which increase load exactly on the coldest nights of the year, when you need heating most.
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.
(It is more expensive to operate than the natural-gas furnace was, though).
Mine struggles if it gets below 30, and might as well not exist below 10. They're not great at low temps.
Mitsubishi hyper heat is indicative of a contemporary inverter design - 100% efficiency to -5f: https://www.mitsubishicomfort.com/articles/mythbusters-heat-...
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...
* 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):
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.
I just did a quick search for "all" units and sorted the result list/table by COP@5F. If one was actually shopping/designing a solution then a more nuanced search criteria would be used.
Further, you'd probably want to do a (US ACCA) Manual J calculation to first determine how much energy is needed (j = joules)
* https://www.youtube.com/@HomePerformance/search?query=manual...
Then the (US ACCA) Manual S (select) to figure out your equipment:
* https://www.youtube.com/@HomePerformance/search?query=manual...
One can lookup the 1% (or 0.4%) of coldest/hottest days for your area, which would help determine what one actually has to typically worry about:
* https://ashrae-meteo.info/v2.0/
* https://www.airequipmentcompany.com/2021/what-does-design-da...
It's fine. The only difference when it's super-cold is that the air coming out of it isn't as warm, so the heating cycle stays on for a longer proportion of the time. But it keeps it 70°F inside no problem at all.
Mitsubishi's maintain 200%+ efficiency down to -4℉ (-20℃) and 150% down to -22℉ (-30℃) [1]. Only a few towns in the continental US get below that, and even those aren't going to get cold enough long enough to make it worth it an an all electric home to switch to your emergency electrical resistance heating.
Their capacity doesn't start dropping until you get down to 23℉ (-5℃), dropping to 76% at -13℉ (-25℃).
[1] https://www.coolingpost.com/world-news/study-proves-heat-pum...
What percentage of the (US) population gets temperatures like that? That's generally mostly IECC Zone 7 (though cold snaps in Zone 6) can happen:
* https://basc.pnnl.gov/images/iecc-climate-zone-map
ASHRAE—an HVAC organization—has data on the coldest and hottest days for areas so that you can design things for the coldest or hottest 1% of the year (4 hottest/coldest days):
* https://ashrae-meteo.info/v2.0/
I think that if you have an older, leaky/ier, less-insulated house you may need to 'brute force' heating your (probably older) domicile. But if you have a <4 ACH@50 air tightness, and reasonable insulation levels, a good portion of the US population could make do with a heat pump.
Mitsubishi 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
At -25C they have 80% capacity:
* https://www.mitsair.com/wp-content/uploads/2024/10/MEM-20240...
A lot? e.g. Chicago gets it every year
>> > What percentage of the (US) population gets temperatures like that? That's generally mostly IECC Zone 7 (though cold snaps in Zone 6) can happen:
> A lot? e.g. Chicago gets it every year
[citation needed]
Per historical weather data:
https://ashrae-meteo.info/v2.0/index.php?lat=41.960&lng=-87....
It is warmer than -16C/3F at Chicago (O'Hare) for 99% of the time (i.e., except for 4 days a year), and warmer than -18.7C/-2F for 99.6% of the time (2 days).
ASHRAE are the folks that publish the heating/cooling standards that are used in building codes for estimate heating/cooling equipment capacities (Manual J) and selecting the right equipment (Manual S).
Here's a PDF with a lot of locations in the US and CA (and other countries further down), and if you look under the "Heating DB" column, you'll find very few US locations that have -30F under the 99% (or even 99.6%) sub-columns:
* https://www.captiveaire.com/catalogcontent/fans/sup_mpu/doc/...
So unless you're in AK, MN, or ND, long runs of temperatures colder than -20F/-30C don't happen too often. Of course if you have a leaky house with little insulation, you're throwing money out the window/door, so the first consideration for a good ROI is better air sealing and insulation.
The CoP is often around 2.0 at those very low temps, though (and of course the heat energy demanded is higher).
Regarding cost, in most of the countries I've lived in a large fraction of the cost in the gas bill was the distribution cost. So once you switch to a heat pump, you also switch to electric cooking and even if heating with electricity would be significantly more expensive you would still win. Is that different in the US?
For September, $12.31 of my $27.01 gas bill was variable based on my consumption.
In December, $84.82 out of my $99.65 total was consumption driven.
I've run numbers on whether it'd make financial sense to go electric for heating, and the break even point is in the 30-40 degree vicinity. With temperatures 20 and under a healthy chunk of the year, unfortunately the added expense doesn't make financial sense.
Until it gets under 30. Then you can watch the power meter crank when auxiliary heat kicks on. And we only keep it 65 in the house in the winter.
Luckily I live in the upper Midwest, so it's only that cold for like 4 months. . . Pretty cool. P.r.e.t.t.y. cool
Most cold climate heat pumps run a defrost cycle to melt ice off the outdoor unit. that's different from auxiliary heat.
There would be an increase only if people were supplementing the heat pump with electric heat, which to be fair is a possibility.
There’s a lot of misinformation about heat pumps, especially by HVAC people who don’t have a lot of experience with them, so they tend to recommend what they’re more familiar with.
But yes, understanding the electricity cost is essential when considering one.
This is completely wrong. The amount of power depends on the temperature delta. When cooling, you are typically not cooling your home to 30 degrees Celsius below the outdoor temperature. However, when heating, you are typically heating your home to around 20 degrees above outdoor temperature. Heating consumes more power than cooling.
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.
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.
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.
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.
(disclosure/transparency I'm the founder of Quilt, a ductless heat pump manufacturer)
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 :)
In this case, contractor should have advised the heat pump would not keep up and recommended a different solution.
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.)
These are entirely disjoint concepts.
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.
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.
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!
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...
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.
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.
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.
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".
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.
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.
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...
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.)
I will say, they seem to have gotten more expensive. It took about $10k to replace ours (it was over 20 years old and replacing coolant+fixing was quoted at nearly half that). Even though research suggested it could be more like a $6.5 to $7.5k cost, it was hard to even get people quoting in a timely manner, let alone getting any kind of a deal.
The article has bullet #1 in problems to solve as "Contractors who default to what they know." This was one of my founding hypotheses to and it turns out I was wrong, this was the hardest won learning yet at Quilt. We originally were fully vertically integrated and had our own installation force because of this reason – we wanted to solve all the big problems, thought contractors were one of them, and so had to become a contractor. But we quickly saw we were getting in the way of our own mission to accelerate the energy transition (because we had far far more demand than we could scale operations to reach it). So in March we (initially cautiously) switched partnering with existing contractors and I have been delighted by the industry reception. There are so so many existing contractors who want modern tech and see working with us as a breath of fresh air. I definitely sold them short and in retrospect it was naive and even a little elitist.
Happy to answer anything more. Also I'd be remiss if I didn't mention that we're growing super fast and just posted an Embedded Software Engineer role: https://job-boards.greenhouse.io/quilt/jobs/4952684007 :)
A heat pump specifically is an AC system that can run in reverse: moving heat from outside to inside.
A previous house the heat pump was sized to work to 14F. They make them that will work down to -25F, but since it gets to -30f where I live (about once every 10 years, but that is enough) we need a backup system so is probably isn't worth getting a system sized to as cold as possible.
Ground source heat pumps are a common option in rural areas - they cost a lot to install ($50k - and this is the cheapest version that needs a lot of land thus rural areas). They are likely to pay off if you live in the same house for 50 years, but the initial upfront costs are high (you do get a house worth $10k more than other heat option). Worth looking into if you are young and have reason to think you will live in the same house for 50 years.
Even as a homeowner who's a bit of an energy geek, it's entirely too challenging to understand the entire space and what options fit one's needs. LLM's help a lot here (if you can trust them!), but it's a funny situation where there's silos of knowledge that are hard to connect.
Once you factor in an electrician and pipefitter for installing a heat pump, plus the cost of the heat pump, refrigerant, and furnace coil, I’d imagine you lose money in the long run.
If you then additionally include the strain on the grid from all these new data centers without enough generation capacity, I’ll stick with natural gas for heating air and water.
The math actually works out in many places unless you have cheap gas and expensive electricity. Its also better then to burn the gas at a power plant at 60% efficiency then 300-400% efficiency at the heat pump than pipe and burn the NG at 80% efficiency in your furnace.
Most of my energy is for HVAC cooling in the south and that is already a heat pump. The house is well insulated and also have solar so along with the water heater and dryer I am around net zero in mid summer and and now that temperature is more mild I am producing much more than using even with one EV as well.
It really nice to have an all electric house along with at least one car and a large solar backup system I am pretty self contained and don't really have to change anything if grid goes down.
Keeping my family warm was a real struggle that week. The next spring, I went to Costco and bought a big tri-power generator and wired up a generator interlock on the electric panel. Now if we lose power, we can run the natural gas furnace & blower with no problems. I can also power the generator from my home's natural gas supply instead of making frequent trips for gasoline.
So I'd say heck no to swapping the natural gas furnace for a heat pump. I'd much rather use natural gas to power both the generator and the furnace/blower than risk needing more electricity to keep my family warm than my setup can handle.
I'm doubly suspicious of areas that combine mass-electrification with reducing availability of the most reliable alternate source of electricity (i.e. generators). California in particular is pushing to make generators increasingly hard to obtain.
There's so much evil being demonstrated today, in real time, that we can't dismiss this any more, it must be seriously considered.
Besides, coercing the general public like that generally doesn't end well: people tend to get annoyed when their basic needs of survival aren't being met - especially if it is a deliberate choice. The people in power will be gone within days.
Edit: Oh actually, I was wrong.(and I guess it makes sense. It would suffer the same problems as an electric hybrid) There is no hybrid gas heat pump for hydronic heating. Basically my entire city is hydronic heating so heat pumps are not an option. However
a bunch of my neighbours have heat pumps and I suppose it’s just heating one room in their house and it’s not even connected to the thermostat of their hydronic heater in any way.. Seems pretty silly to me. At least you get an air conditioner out of the deal so that you can use more electricity in the summer.
You can then make your own hybrid with a resistive electric boiler or a gas boiler wired to second-stage or emergency heat.
My 1920s house with radiators and terrible insulation outside of Boston runs with return water temps in the low 90s in shoulder season and 120°F when it’s 12°F outside, using outdoor-reset/weather-compensation.
Those return temps are entirely compatible with air-to-water heat pumps. (And result in 22-24 hour run times per day, which makes for extremely comfortable heat, despite the generally lacking insulation.)
I don’t have one because HVAC contractors are living in the 1990s and want to do a 3-hour, 2-person combi boiler install for $10K in profit rather than think through how to do anything unusual.
Many of us are proponents of heat pumps thanks to reduced costs and emissions *but* we've not had a generally good experience possibly (!) as a result of bad installation and definitely due to limited numbers of indoor heads (if I close my main bedroom door, the rest of my upper floor has no heating/cooling).
There's always someone in the community frustrated that their house is too cold/hot, that the condensation drains are blocked and water is running down an interior wall, that an indoor head or the condenser is having problems, or that there's unexplained coolant leak.
People moving into the community are inheriting issues with at least 2 homes having to augment/replace the system. To save breaking into the walls, this often necessitates putting the power, coolant and drainage lines on the outside of the house and then boxing the result.
We're saving money on monthly bills (probably; we don't have a comp) but many of us have spent quite some $$$ on maintenance and replacement equipment.
I've spent 1.5 years in a brand-new building with Mitsubishi heat pumps. It had some initial trouble with a faulty electronic component, but afterwards it worked quite fine, needing little if any attention.
I think it cost about $13k for heat pump and furnace and labor, maybe a bit more with tax, and I got ~1.7k rebate/refund of some sorts? Or 1.3k? I don't fully recall why but it must have been government sponsored.
My ongoing energy costs are about the same, but the mix completely switched from gas to electricity. I cook with gas so there is just a bit every month, but virtually no heating with it, the gas hardly ever starts except in the height of winter. If I only had solar to feed it with sun, but the house location with shade, hill and trees isn't suited for it. Instead I pay a little extra to energy company to presumably source my electricity from solar. Works.
Well, this has already happened; living in a third-world American country, I've been heating my houses in winter with heat pumps every winter for many years (even though they iced up occasionally) and most air conditioners here are already heat pumps. Frio/calor, they're called.
But, installations strictly for heating are probably never going to happen en masse. In https://news.ycombinator.com/item?id=45698730 I analyze the costs. It turns out that heat pumps cost around 39¢ per peak watt they save, while low-cost solar panels cost 6.5¢ per peak watt they produce, so it's almost always cheaper to install enough solar panels to heat your house resistively. And that gap is going to continue widening for the foreseeable future.
Our heat pump, a cheap-shit Electrolux mini split assembled in Tierra del Fuego, broke down last winter; somehow the refrigerant escaped. The repairman did a pressure test with nitrogen but couldn't find a link. He pre-emptively soldered shut a pipe that had been crimped shut at the factory, and pointed out that, probably, if we hadn't been using it as a heat pump, it would have been fine. Certainly it would have had many fewer hours of operation. We ended up spending about US$100 on the repair, which is the price of 1500 peak watts of solar panels. I think that brings us to about US$500 total spent on the thing—insignificant to people in the US, but a significant chunk of change in most of the rest of America.
Heat pumps are an energy-crisis-era efficiency measure to conserve energy. But energy is no longer scarce. After 50 years, the energy crisis is, if not ended, at least ending. If your house's solar panels are producing more energy than you can use or sell back to the grid at a decent price, the energy to run a resistive heater is free.
Now, I will gladly point out that I have a roof of solar panels, and benefit from subsidies: It's important to understand that solar currently is unsustainable economically and will only be sustainable with more R&D on storage.
You're right that you do need energy storage, though. Even sensible-heat thermal energy storage is completely adequate for this purpose, and it's very cheap, on the order of US$2–3/kWh. See the sand-battery outline I wrote yesterday in https://news.ycombinator.com/item?id=45690085. Electric night storage heaters are widely available off the shelf in many countries already, though not in the US.
For some other kinds of energy storage, it's debatable whether utility-scale storage or household-scale storage is more efficient; you're trading off economies of scale against transmission and distribution losses and transaction costs. But low-grade thermal energy storage is clearly better at household or neighborhood scale; my design outline linked above comes to a price per kWh that's 3% of the price of the batteries needed for BESS, and maybe 15% of the optimistic cost estimates for sodium-ion. You have to reduce the energy to low-grade heat up front to store it so cheaply, but that makes it hard to redistribute later—to redistribute low-grade stored heat from a central energy storage facility, you need something like New York's steam district heating systems. It's far cheaper to store the thermal energy at the point of use.
This is not a new idea. It's the idea behind adobe walls, Russian stoves, rocket mass heaters, electric night storage heaters, dol beds, kachelofens, kangs, earth-bermed walls, Trombe walls, and ondols. People have been doing this for 7000 years, without an electrical grid or, for that matter, electrical power at all. It definitely doesn't rely on net metering!
The problem was that the lineset was in my walls, so replacing it would require ugly lineset in a highly-visible place on my house. All the quotes to fix / replace it were absurdly expensive.
Because the mini-split was for a room that I use occasionally, I just use a portable air conditioner and a space heater.
I suspect it's especially bad with new builds, as new builds are a race to the bottom and every subcontractor is fighting to get the lowest bid. The best way to make it cheaper is skip steps, and that hurts in the long run. Sorry you ended up in that situation, crummy experiences like this set the industry back. For what it's worth, the same corrosion could happen with a traditional AC system too (it's not just heat pumps). But the difference is, often those refrigerant lines don't get as hidden on interior walls as the ones for ductless mini-splits do.
Where it did make sense was when I was getting solar. It was only a few thousand since I already had the trades out and reducing the load was important for the ROI on the panels.
$20k USD is insane though. I live in Ontario and we paid $12k CAD (pre-government subsidy) for a modern heat pump with a backup high efficiency furnace for when temperatures dip down to -40 or lower.
Honestly, just piling more insulation in the attic and doing an energy audit will probably put the ROI out another 10+ years...
I'm hoping the newer window units that are being rolled out to the NYC market will be good enough to put downward pressure on the outrageous prices in the installation market. Or maybe I'll just dedicate a weekend to DIYing :P
Mini-splits tend to be much cheaper than full installations.
Makes sense for living room tho.
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
C$4,500 electricity (heating + cooling + misc)
C$500 propane (hot water)
C$5,000 total.
C$2,000 electricity (heating + cooling + misc)
C$500 propane (hot water)
C$2,500 total.
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.
I generate 2/3 as much as say SoCal, and less evenly (a lot more in summer). Cooler temperatures improve solar panel efficiency too. There are online calculators if you want to check.
I’m so happy for you.
It's insane and really made me look into the DIY installs. Even if I broke 2 of those it would still be cheaper than one professional one.
Solar install is another scam. All those companies want to steer you into a PPA rather than let you buy panels.
Maybe? Or maybe the tech is not superior enough (considering the overhead) so nobody cares.
There's a few parts to this. Everything has to be carefully sized - power, pipe sizes, unit locations. You need to put a house's thermal profile (how much heat loss, how much air leak, how much thermal mass) along with the regional thermal profile into an engineering calculation which computes what you need.
Thermographic inspections are a thing.[1] Usual price is around $400. They're not very standardized. You get IR images of a house, which is good for finding leaks but not quantitative enough to size a heating and cooling plant.
This would be a great drone application. Fly over and around the house. Build a 3D model of the house and paint heat loss on top of it. Crunch on data to get the engineering info needed to correctly size HVAC. Also discover big heat leak points. Turn this from experienced guessing into measurement.
Then submit that data sheet to multiple sites that offer heat pumps.
Startup opportunity here.
[1] https://www.energy.gov/energysaver/thermographic-inspections
Forced air is a terrible way to heat a building yet thats how most homes are heated, and it is good enough for most people.
If you perfectly size a furnace for the coldest days of the year, it is now oversized for the other 90% of days.
The cheapest way is to install a multi stage heating/cooling system that works on first stage most of the time, and second when it needs to, like having 2 small furnaces. This passes the ‘good enough’ test for the vast majority of homeowners.
Unlike gas furnaces which basically can only do ON or OFF, heat pumps can regulate the heat with much higher granularity.
What certainly calls for innovation is managing the labor costs. In my case installation involved way too many people and way too many visits.
They now make really efficient refrigerators for your kitchen that you get to throw out every 2-5 years.
In fact, efficiency was the main reason I wanted a mini split in the first place. It just bugged me to _not_ pump the heat entirely outside the structure. And I paid a bit more for that versus just using a window unit or “portable” AC. All we’re talking here is the location of the condenser coil: inside versus outside. It just makes sense to put it outside, with just a small penetration in the building.
Well, during electrical inspection apparently I paid too much. After paying more than a certain threshold for converting an unconditioned space to a conditioned space, I now need to insulate the accessory structure to a certain degree in order to pass code.
The kicker is, the only way I can insulate the space to meet code is to insulate with polyiso (aka styrofoam) because the structure is so small. So, I guess in an effort to be “green” according to local government, I need to rip out the mineral wool insulation, dump it and replace it with styrofoam. Or put the mini split in the dump and buy a cheaper less efficient unit like a window unit.
I’d save approximately $0.30 a year on energy costs to insulate to code versus what I have now with the mini split.
This whole industry is stupid and that’s because it’s regulated by idiots.
Name and shame: this is Chapel Hill, NC.
A third of the country rents. Renters pay the utility bills. Landlords pay for appliance upgrades.
Why would the landlord put any effort into upgrading appliances when the cost of not upgrading them is borne by the renters?
I've never rented at a place where they didn't want to fix broken equipment with the cheapest possible replacement. And no renter would ever consider purchasing a major appliance like this since they'll end up priced out before they recover the cost in utility bills.
They're a nice technology, but our incentives are all wrong for a lot of housing stock.
galoisscobi•7h ago
Right on. I have a heat pump water heater and a heat pump heating system in my HVAC. Getting those installed felt like swimming upstream. Most contractors would try to dissuade me from them.
Luckily, I found a contractor who was skilled and knowledgeable about heat pumps and rebates (back when govt thought climate change was real). Very happy with my heat pump tech.
jbm•7h ago
Spooky23•4h ago
In my area, about 75% of the HVAC companies have been swept up. Prices are up 75-150%. I got my gas furnace replaced to to beat the ban, and had a fireman who works a side gig do the job for $15k. The bids from the companies ranged from $25-85k
bamboozled•7h ago
brendoelfrendo•7h ago
Glyptodon•7h ago
Edit: (or so you mean mini splits?)
brendoelfrendo•6h ago
notyourwork•4h ago
rootusrootus•3h ago
If the furnace is a serviceable natural gas unit, keep it. It makes a better backup than strip heat.
ortusdux•7h ago
darth_avocado•7h ago
1. They are EXPENSIVE. The equipment itself isn’t that expensive tbh but installation is pretty expensive. The government subsidies have made sure that the contractors jack up their own prices by as much.
2. I end up paying more in utilities because electricity is very expensive and heat pumps aren’t nearly as good at heating in the winters as old fashioned gas furnaces when it comes to the cost.
I made the massive investment because I could and I eventually want my house to run completely on rooftop solar as a way to reduce my carbon footprint. But the cost is nowhere near mass market adoption price range.
ssuds•5h ago
That said, I've found that in most cases (assuming you're on the right electric rate plan, that's a whole other conversation, see https://news.ycombinator.com/item?id=42763695), most homeowners in california actually see operating cost parity or a slight decrease, even with super expensive electricity. Silicon Valley Clean Energy recently did a study substantiating this: https://svcleanenergy.org/wp-content/uploads/Bill-Impacts-of...
darth_avocado•5h ago
But you’re missing my first point though, installing a heat pump system comes with a price tag of tens of thousands of dollars. I’m not doing that if my operating cost is at parity or a slight decrease. It’s the same reason people are no longer incentivized to install solar. And to add to that, installing heat pumps also come with additional costs that can range anywhere from a few thousand dollars to replace the main electrical panel to tens of thousands of dollars for a full electrical upgrade if your house is on knob and tube wiring to reduce fire risks.
morshu9001•4h ago
parpfish•3h ago
kevin_thibedeau•3h ago
next_xibalba•1h ago
doubleg72•2h ago
ssuds•4h ago
I think there's some nuance to that, though. Even replacing a furnace + AC in California amounts to tens of thousands of dollars! It's not that heat pumps are expensive, it's that construction work in general is expensive.
When you frame it in terms of percentage of home cost, it actually feels a lot more reasonable. Robert Bean is a pretty respected voice in HVAC, and shared this article a few years ago (https://web.archive.org/web/20150210053806/http://www.health...). The gist is (and this is focused a bit on new construction, so not entirely apples to apples) that you should budget 3-5% of the home's cost for a bare minimum code compliant HVAC installation. When you look at it in that lens, $20k to replace the most complicated mechanical system in a $3M home is less than 1%.
I recently read a piece about the "Cost disease in services" that was really enlightening (https://growthecon.com/feed/2017/05/15/What-You-Spend.html).
"Productivity growth in the goods sector raises the wage in that sector, but also raises the output of that sector. So the ratio of wage to output - a measure of the cost of a unit of output - stays constant over time. Higher wages in the goods sector put pressure on wages in the service sector, so wages rise over time there. But (taking the exteme position) productivity is not growing in services, and so output is not growing. The ratio of wages to output in services - a measure of costs - is thus rising over time. This is the “cost disease of services”."
While I don't think that's all of it, it is a helpful framing of the economics around these dynamics.
There are some companies out there that are truly price gouging. But many are just pricing around the true cost of labor and to run a construction business. I've done a little writing around this topic too: https://www.heatpumped.org/p/pricing-transparency-peeking-be...
Ultimately, I would love to see upfront prices & operating costs for heat pumps both fall. But there are a lot of tough realities baked into the cost of these systems. They are still a very logical choice for most homeowners at the time of failure. Especially with rebate & incentive stacks in many places, a heat pump actually works out cheaper than a new furnace + traditional AC for many homeowners.
psunavy03•2h ago
ssuds•35m ago
Even if we changed the number to $1M, the overall point remains the same
kragen•4h ago
Mine cost US$250 for the machine, refrigerant included, and another US$80 for the installation. We've had to have it fixed twice due to factory defects. Its heat output is 3400W, nominally consuming 941 watts of electrical power. It's not a great machine, but you're smoking crack.
ssuds•4h ago
Skilled labor in the US is expensive! Most of the install costs come from labor, not equipment. Tens of thousands of dollars is pretty typical for a heat pump installation.
(For what it's worth, the person you're quoting is referencing a whole home system, either ducted or multi-zone ductless. I think you're referencing a single-zone ductless. Those are cheaper, but still are typically $5-10k installed from a licensed contractor in the states)
kragen•4h ago
ssuds•3h ago
kragen•3h ago
tomrod•1h ago
darth_avocado•8m ago
pureagave•4h ago
thevillagechief•4h ago
sitharus•3h ago
rootusrootus•3h ago
yojo•3h ago
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 lines.
So maybe $1850 all-in, plus 8 hours labor. I’m sure a pro could do it in half the time. But the low end for a pro install is $5k.
I get that they have insurance and warranty or whatever, but that’s a damn juicy margin.
raddan•3h ago
EngCanMan•1h ago
Come to your house to quote, and only land 1/4 quotes maybe.
Schedule the workers
Order the equipment.
Get an electrical permit.
Pay for the truck and all the tools.
Insurance for the company and trucks.
Advertising costs
Warranty and callbacks
I can assure you that this is not the get rich quick scheme you may think it is.
relaxing•30m ago
It is in fact a get rich scheme.
smileysteve•3h ago
Tuning a heat pump vs resistive heat is a much tougher game than it should be. In a moderate climate, I use my ecobee to ensure aux heat doesn't come on until it's below freezing, and it should only come on if something has gone wrong at that point too. Unfortunately, many thermostats by default will use resistive heat in relatively normal scenarios, of worse, when you've programmed home and away times intended for efficiency but disparate enough to activate resistive heat.
relaxing•34m ago