This persistent myth just needs to go away. People use heat pumps all over Scandinavia, including in the arctic circle. They are extremely popular there. They were early adopters of this technology there decades ago.
There are two popular varieties:
- Ground source heat pumps. Those work pretty much anywhere; just dig below the perma frost and you are good to go on the northern tip of Canada, Alaska, Norway, or wherever. Works great, ground temperatures tend to be very stable and it actually goes up the deeper you dig.
- Air source heat pumps. The expensive ones still work okish at extreme temperatures like -25-ish degrees C. Which is a reason these are actually more popular than ground sources even in places (e.g. most of Scandinavia) that reliably get such temperatures each winter.
We've been using 'reverse-cycle air-conditioners' for heating in Australia for decades. I'm puzzled as to why there is any debate at all on their use for heating. A heat-pump is far more efficient for obtaining heat than direct resistive heating using electricity.
Many houses here use no other form of heating at all. And then at the press of a button, we get cooling in summer too. What's not to like?
* I also have a heat-pump condensing clothes dryer. The overall heat thrown out into the room is extremely low. The hot-air comes out the hot-side of the heat-pump to dry the clothes. The warm-moist air then passes over the cold coils, condensing out the water from the clothes and returning the heat to the cold-side of the heat pump which then pushes that heat-energy out the hot-side, producing more hot air to complete the cycle. I've had this Miele heat-pump condensing dryer going strong since 2009 - 14 years.
I've seen heat-pump base water heaters, but never a clothes drier. That sounds interesting. Now I have something new to research, thanks! Personally, I'm always curious why there isn't a more unified heat-exchanger system built into the structure of a house. HVAC, Water, Refrigerator, they all need to move heat from one place to another, why not work together?
I've tried to make the idea work in my head many times but my conclusion has been that I don't think there's quite enough co-incident demand for heating and cooling in the average house. For example, yes, I could generate all my domestic hot water from heat from air conditioning in summer, but in winter I need to be able to generate it plus heat the house, so I need enough capacity to generate that heat from the outside air when I'm not using air conditioning (so I don't save on not needing as much capacity), and the efficiency gains probably aren't worth the extra complexity.
For applications like commercial buildings, public swimming pools, industrial sites, etc. can (and increasingly do) definitely benefit from that kind of combination though.
I think the big issue is the different "tuning" for each heat pump system. For example, a heat pump water heater needs a different maximum temperature than an air conditioner, and has much different cycling behavior. This leads to very different design decisions, including refrigerant choice, pressure, compressor type, whether the refrigerant loop is even serviceable, etc. (Some appliances operate at a refrigerant pressure so high that they require being fully assembled at the factory, which would be a non-starter for a manifold system like we're discussing.)
I think this might eventually become a thing once science gets us far enough that there's an "obvious" refrigerant choice for most applications, but we definitely aren't there yet. There are hundreds of different kinds that perform better or worse in different applications.
AFAIK all of the big commercial systems that do multiple different types of heat transfer use water to do it, thus bypassing the entire refrigerant selection issue. Right now the most advanced we can do is VRF ("Variable Refrigerant Flow") systems that can individually select air handlers for cooling or heating (i.e. move the heat from one room to another). These are still commercial units and not really available for residential installs.
There’s a reason new houses get built with geo based heat pumps in Finland.
This enables your hot water heater to use the same circuit to heat water - that decreases your hot water bill to around a third, even in winter as the necessary heat isn’t taken from the indoor air but from the ground.
It's just the Yanks that have subsidised natural gas in many states, and a messed up energy infrastructure that gives electricity prices in the same range as what we have in Europe while being at war.
Not a source, but it's more common to have heat pumps in the southern States where winters aren't that bad. I'm born and raised in Arizona and they seemed to be common in houses after the 1973 energy crisis. My grandparents house in Tempe, AZ (was built in like 1950's) did no have one. A house I purchased in central North Carolina had a heat pump. I'm now around Washington DC area in Virginia, and we has gas. I think a simple explanation is that natural gas is almost a by product (certainly from landfills, which is how most USA disposes of trash) and is very cost efficient. Also the energy crisis changed the outlook of house building. I hope that helps explain it some, sorry I don't have any concrete facts I'm typing on a small keyboard.
Yes. Although I have noticed that some people here in Australia go from the belief that "air conditioners use a lot of electricity" so therefore have the misconception a (resistive) electric heater must be cheaper to use than the reverse cycle AC (heat pump). So there is a bit of an education gap even here where they are quite ubiquitous!
I also do want to get a heat pump dryer (it's next on the list after my recently installed heat pumper hot water system), but I don't have quite enough space in the laundry and apart from two or three wet weeks a year I'd mostly only use it to fluff up towels (which is why I don't have a dryer at all at the moment)...
Electrical bills come every three months. ALL electricity use is lumped together. So it's a bit hard to disect out what each usage-type is costing, unless you use one of those meters and study up average use over a period. Even then, some things like water heating and even aircons, are directly wired into the mains switchboard, so you would need an electrician to separate out those circuits for measuring. So it just doesn't happen.
Heat pump dryer system is state of the art for efficiency. I saw some complains by American that it takes too long time for drying, but I don't know why they need to dry things so frequently.
I was thinking about this anomaly yesterday. Then I remembered that most US electrical outlets are at 110 Volts instead of the more usual world-wide standard of 220 volts. So most stuff in the US is under-powered by EU or Australian standards. Being under-powered, it would take longer to dry your clothes.
(That's also why they don't seem to use electric kettles in the US commonly as is normal in 220 volt countries)
I like mine, but it has a small capacity compared to a standard dryer, and we find that over time water slowly condenses inside of it, so we have to drain it a couple times a year to stop it from shorting its control panel. Not 100% if it's design flaw, micro leak, or what. 8 or 9 year old LG unit I think.
If I’m doing 3 loads of laundry for the family, I don’t want a 2.5-3 hour dry cycle to make laundry take all day (or make me do laundry of half the days of the week).
??? That's excessively long. Our heat-pump dryer takes about 20-30 minutes to do one of our loads.* The dryer invariably ends up waiting for the washer to finish.
* Our loads aren't excessively tight in the machine. You have to allow room for the clothes to tumble loosely thus allowing lots of surface area for evaporation.
I quickly googled for “how long does a heat pump dryer cycle take” and got several answers in the 2.5-3 hour range, which is long enough to provoke complaints.
Obviously, if every heat pump dryer took 20-30 minutes, you would not hear complaints about that (that’s much faster than my gas dryer).
Power-input. US dryers would typically work on 110 volts mains. Those similar dryers in the EU or Australia are working on 220 volts mains. Took me a while to click on why the great differences in working-times. 15 amps wiring in the US means 1650 watts, the same wiring in EU is 3300 watts.
That's not it. Electric dryers in the US are overwhelmingly 240V and on a 30A breaker. At 80% of rated, that's 5.7kW available. (Gas dryers here are typically on a 120V, 15A circuit.)
Every heat pump dryer I looked at on the home center's website is 240V. (Edit: I found one Miele on another home center that was a 15A@120V.)
The myth exists because the US is probably 10-20 years behind Europe and China in terms of HVAC and insulation technology. I recently had some reasonably high efficiency heat pumps installed at my house, and I’ve been very unhappy with the low temperature performance. It doesn’t even get very cold here—rarely below 5F (-15C) and a record low of -8F (-22C). The heat pumps I got (recommended by the well-regarded local HVAC company) operate at just 40% of rated capacity at 0F.[1] Meanwhile, Chinese and Japanese-made inverter driven heat pumps will happily go down to -5F at 100% of rated capacity, and -22F (-30C) at 80% of rated capacity.
[1] You can of course get a much larger heat pump to compensate, but that leaves the unit way over-sized for cooling loads.
I recently saw a transport nerd claim that US and Canadian (though interestingly not Mexican) busses were substantially and objectively worse in build and ride quality than European busses, even when they share the same engine components.
Which I guess similarly explains a lot of weird conversations and people talking past each other where busses are concerned.
In my local market, if you ask an installer for a heat pump, you get something from Japan or Korea. I’ve never encountered an American unit.
(I’m referring to normal air-to-refrigerant-to-air heat pumps. I know of a really weird system that is thoroughly American and an utter pain in the arse to replace because it’s specialized and undocumented. It’s quite loud, too, because it’s single-speed, and that single speed is waaaaay too high.)
The Asian brands make products for the US market—often through subsidiaries that were originally US companies, such as Goodman and Amana. Basically stuff that complies with US codes and standards, and that US HVAC installers can fix without learning anything new. Daikin makes a ton of stuff they don’t sell in the US. Owens Corning makes high density fiberglass batts you can buy in Canada but not in the US.
Sounds like the units you are describing don't have an efficient (read 'big enough') heat-exchanger which is why they aren't being effective in not-so-low temperatures. The temperature of the cold-side should not be below outside ambient temperatures if the heat exchanger coils are sufficient.
In other words heat-energy should be going into cold side of the heat-pump (even at a low temperatures) at the same rate as it is coming out the hot-side at high temperatures. Reduce the heat in, and you will reduce the heat out.
Sounds like they undersized your installation in order to quote you a lower price. The efficiencies of heat pumps are well documented as are the weather patterns in your area. So, they should/could have known better.
Two solutions to this problem:
1) get a bigger/better heat pump.
2) improve you building insulation and figure out where you are losing energy.
I live in FL and we have a backup resistive heating element that kicks in as needed. Mostly only comes on a few days in the year or for short bursts when there's a cold snap that the heat pump can't keep up with.
This is fine until everyone in your neighborhood has one and it causes a brown out. (Peak amperage for the heating strips on my heat pump are three times as high as for the heat pump itself at maximum cooling load.)
Air source heat pumps are super popular in Poland too, this winter it was about -20C for couple weeks straight and not had any problems, toasty house without any issues. The key is that the heat pump exchanger really needs to be huge(ours is taller than a person) to get the heat out of the air.
I've been on zoom calls with two separate co-workers who are all bundled up because their heat pump can't handle the weather. It doesn't mean that the technology is inadequate in principle--probably their systems have some problem that competent HVAC installers know how to avoid.
But its an unfortunate fact that there are places in the US where installers that recommend heat pumps can't be found for 100 miles. It doesn't really matter if I'm technically correct about the merits of the tech in principle--if I can't find somebody to fix my system and my pipes start exploding, I've still made the wrong decision.
Also, heavy snows cause power outages in places where tree limbs fall on overhead lines. If gas outages happen... well I've never experienced one. Sure, if I lived in Norway I'd have a government that cares about updated infrastructure and I wouldn't have these problems, but since I don't, I do.
Given my local constraints, a dual-fuel system sounds pretty great.
Gas outages happened at a large scale in Texas when they were struggling with a bit of cold weather. When they needed it the most, it failed them. Coal plants also struggled. Both had challenges with supply of fuel and cooling water being disrupted. That kind of systemic infrastructure failures is on the rise in the US. There are all sorts of reasons why governance just isn't great in the US. But the reality indeed is that things are unlikely to improve on that front.
Which are all good reasons why the market for domestic solar, batteries, and heat pumps is so hot right now. The US is no exception to this.
There are power outages in Norway too - though there are typically years between incidents, and years and years between incidents lasting a day instead of hours (with the exception of certain avalanche-prone areas where this happens much more often than people would like). So my home has a backup system - as do most houses. And that's a wood heater. But my house is so well insulated that it takes a day even in the coldest of winter before I actually need to use it if this happens. Newer houses are also quite much better than mine in this respect.
There are two popular varieties:
- Ground source heat pumps. Those work pretty much anywhere; just dig below the perma frost and you are good to go on the northern tip of Canada, Alaska, Norway, or wherever. Works great, ground temperatures tend to be very stable and it actually goes up the deeper you dig.
- Air source heat pumps. The expensive ones still work okish at extreme temperatures like -25-ish degrees C. Which is a reason these are actually more popular than ground sources even in places (e.g. most of Scandinavia) that reliably get such temperatures each winter.