Are heat pumps the best choice for heating/cooling a home?

A recent thread here was talking about how a power plant works and heat pumps were mentioned.

I have seen a few videos recently touting the advantages of a heat pump to heat/cool your home (see some below).

But, while I trust the video producers of the videos below I am dubious. How is this only now a thing? The mechanics of it seem like something we have known a long time.

It seems like there has to be a catch to it. Otherwise, everyone would do it.

So, why isn’t everyone doing it?

Heat pumps can work very well.
But, they are not great for climates that get very cold, although there are newer units that are much better these days.

They are expensive to install initially, but if an A/C needs to be replaced, it’s only a small increment to upgrade to heat pump. We have a 5-ton unit that works extremely well, but heating in the Phoenix winter (lows never going much below 20°) is a different story than say, Duluth.

I’ve had a ground-linked heat pump for heat and AC at my house since 2008. There is a heat transfer loop buried about 6 feet beneath the field east of my house. The heating & AC industry frequently refers to this as a geothermal system, which is somewhat of a misnomer. I think the heat pump part of the system works sufficiently well, although the the air circulation within my house is not up to par (at least not to my satisfaction), so different parts of the house are noticeably warmer or cooler than others.

The 911 call center next to where I work also has a ground-linked heat pump, but it uses a vertical heat transfer loop in a deep well shaft.

Edit: Apparently the current terminologies are ground source heat pump or geothermal system.

Regarding the Technology Connections, he has a second video (on his second channel maybe) where he gets into the numbers about specifically WHY it works so well for him and why it may not work for others.
If you haven’t seen it, it might be worth watching.

ETA, I think this is what I’m thinking of. I could be wrong. I’m quite sure he’s spent time talking about heat pumps in other videos as well (in fact, something to keep in mind is that as thorough and generally unbiased as his videos are, he is a bit of a heat pump fanboy).
I only skimmed through it quickly, but the one I’m thinking of is when he gets into how much he pays for electricity throughout the day and why he can heat/cool his house mainly at night instead of all day.

Depends on a number of factors, most importantly the climate (specifically how cold it gets in the winter). Below a certain outside temperature the heat pump performances drops substantially - in colder climates they are usually installed with a backup system to help out or take over, most commonly resistive heating elements which get very expensive to run.

Here in the desert they are great, no supplemental heating required. They don’t raise the air temperature nearly as high as a gas furnace, so the air does not dry out like it usually does with forced hot air heating (it’s more like forced warm air heating). Recovery is longer than with a furnace.

Some friends got one installed last summer that works down to -5F, which is pretty cold. That seems to be standard for residential units, and is just a regular air exchange heat pump. I think -5F is where the heat pump is in parity with the auxiliary resistive heat strips for efficiency.

It made it through one Denver area winter with no issues.

As to “why is this a new thing”, it’s not. Heat pumps have been in use for decades.

A heat pump will never use more energy than the equivalent (in terms of watts of heating) purely-resistive electric heating system. But depending on local prices for electricity and natural gas (or other fossil fuels used for heating), it may be cheaper to get heat from gas, instead. And even for a given wattage of heat, a resistive system is simpler, and so it’s easier to set it up to heat only specific rooms, or to heat from the floor so it’s comfortable to walk on on cold winter mornings, or the like (you can do all of these things with heat pumps, too, but it’d be more complicated). They also have moving parts, which are potential points of failure.

In the videos in the OP they say that resistive heating is 1:1. A watt of energy in is a watt of energy out. But, they claim, heat pumps do better than this (and don’t break the laws of physics).

As an aside, I live in a hi-rise with floor to ceiling windows that are the outside walls. There was a lot of howling from residents last winter (in the biggest units) getting $800 electric bills and they have mostly resistive heating. I live in a smaller unit but I admit I felt the pain of high electric bills too (although nothing as bad as $800).

This is correct. They’re getting the extra heat from the outside air (or earth). Which is why they work better with small temperature differences: When it’s super-cold out, there just isn’t as much heat available from the air.

I wonder if there are any weasels who would install an air-to-air heat pump that scavenges heat from some other interior (heated) area of the building. :grin:

Is this something that can be done (in a reasonable way)? It has occurred to me that the heat from lower floors is coming my way but my heaters still work pretty hard (in no small part that we have concrete floors that are 6" thick…give or take but close enough).

I tend to agree with Alec (Technology Connections) that if you have an air conditioner, there’s little to no reason it shouldn’t also be a heat pump. Since even climates that have very cold winters still have air conditioning, it doesn’t matter if the heat pump can’t provide all the heating because the alternative is that it produces NONE of the heating, so you’d have gas, propane, oil, or whatever anyway.

Here’s some reasons you don’t see more combined heat pump/gas furnace systems, or just heat pumps in general in more moderate climates (some of which Alec touched on in his videos):

  1. North American HVAC equipment is cheap garbage. There’s equipment out there with SEER ratings over 30 and EER ratings pushing 20, but since few here care about energy use and only care about upfront cost, SEER 13 A/C units are all you’re likely to get without a special-order and a lot of hemming and hawing from your HVAC contractor.
  2. Even if it’s garbage, there’s still a marginal cost increase in a heat pump versus just an A/C if for no other reason than the refrigerant switching valve and some extra circuitry and the defrost timer/sensor. When pinching pennies…
  3. Those HVAC contractors and techs are notoriously conservative. “You don’t want to replace this 40-year old A/C that’s costing you $700/month to cool your home with that new high-efficiency garbage, it won’t last!” Also “A/C’s are for cooling, not for heating, we don’t do that here!”
  4. The higher the efficiency (and less common) the more difficult it is to get parts and to service. If the service tech can’t buy a replacement capacitor from Billy Bob’s Supply House and keep them in their truck, or they can’t check the refrigerant charge with a divining rod, then they don’t want to work on it. More seriously, any heat pump specific parts/models are going to be harder to come by farther north than in the south.
  5. A smart thermostat, if not some separate smart controller, is necessary to properly switch between normal heat pump operation and a gas furnace. That adds expense.
  6. Since furnaces in colder climates are usually installed in the basement, it also means the refrigerant coil is above/downstream of the furnace. Therefore the furnace can’t be used to boost heat pump output, it has to switch from one to the other, which requires knowing the outside temperature and other conditions of the system.
  7. All-electric heat pumps have strip heaters in case the heat pump goes down, as a booster for really cold days, when the thermostat is turned up (the strips are downstream of the refrigerant coil so that works fine), and when the outdoor unit is defrosting. Modern gas furnaces take a while to start up and get to temperature, so they’re not well-suited to tempering the blast of cold air from the defrost cycle, certainly not without smart controls. That short a cycle can be rough on the furnace too, leading to excess moisture condensation and acid buildup.
  8. Cost of electricity can be a big one. California has a ton of gas heating, even in Los Angeles, because electricity is so expensive. I’m not sure it’s entirely rational or the numbers actually favor gas, but the perception is there.

Are any of these problems insurmountable? No, but if building codes aren’t updated to require better efficiency, which is always lobbied against by the powerful homebuilding lobby and anti-government sorts, then they’re just going to keep installing the same cheap crap that they’ve always used.

I heat my home with heat pumps. The only problem I have is that if I’ve set the thermostat back, like if I’m gone for a week, I have to slowly raise the setpoint. If the setpoint is more than a degree and a half above the measured temperature inside the house, the system decides the heat pump isn’t keeping up and kicks in the resistance heaters, which drop my efficiency to 1.0. I have to sneak up on the temperature increase raising the setpoint a degree and a half at a time.

Heat pumps heat a home in a more energy-efficient way than a typical gas-fired, oil fired or electric furnace. However, as noted they traditionally are installed with an aux/backup heat source for when the heat pump cannot keep up–frequently an electric furnace. Due to the historic norm that electric furnaces are more expensive to run than gas fired or oil fired furnaces (in most parts of the U.S. this is true due to the price of electricity vs oil or gas, but this obviously varies with both the markets of all involved energy sources), this means that historically if it was really cold a lot of the winter your heat-pump+backup system would be a lot more expensive to run than a comparable gas furnace. As noted newer heat pumps are more effective down to fairly cold temperatures that make them pretty reasonable for most of the continental United States.

I have an in-wall wood furnace/fireplace in my living room which I use in the winter to prevent the heat pump from needing to kick in any supplemental electric heat. I have about 10 acres of forest next to my house, so I always have a ready supply of free firewood.

My guess is the price. I switched a few months ago to a ductless mini-split air source heat pump system - and the number on the invoice was around $35K. I didn’t pay for it - a “rebate” from the electric company that went straight to the contractor did. I just happened to find out about the rebate program the same year that I was going to have to replace my oil furnace - and it’s a good thing I found out when I did, because it took weeks for the contractor to get to me and it was installed shortly before the rebate program ended.

I’m sure my electric bill will go up some - but I won’t have an oil bill any more, these units work better than my window air conditioners ever did and I no longer have the problem of “when the first floor is warm enough, the second floor is a sauna”

Last fall we looked into getting rid of our forced-air electric furnace (new ca. 1984) and replacing it with a heat pump. All the existing ducting for the furnace would’ve been able to be reused, so the quote was just for the heat pump, the filter unit (which I guess is a separate device installed just upstream of the blower) and the thermostat, all installed. I don’t remember the SEER rating, I do remember it had an auxiliary heat “strip” for when the outdoor air dropped below 15°f or so – which is almost never here in western Oregon.

Anyway, the quote was $7500. We would’ve had to have an electrician come and do some prep work beforehand, which would’ve been another ~$1200.

So yeah, price is a big issue. We figured it would save us about $200 on the electric bill in the winter (the furnace is on a dedicated 90 amp circut, the heat pump would use a fraction of that). We’re still planning on upgrading to a heat pump eventually but there are other things that are demanding that $8700 first.

It isn’t “just now” a thing. I read an article touting the benefits of heat pumps 30-some years ago.

Here’s the issue – heat pumps never have been very common. For whatever reason, they never have gotten traction in the general population. So every so often, you get waves of articles/videos/whatever touting them, and every single time that it happens, some people learn about heat pumps for the very first time. Which means that, in a certain sense, heat pumps are always this new-fangled thing that’s just around the corner.

But that is moot if the homeowner has a good solar [or other electrical generation form] set up. I mean, the cost of electricity isn’t a consideration once the generation system is in place[I know someone who has a small river driven hydroelectric system, got to love 70s Mother Earth News projects. Been more dependable than the grid, actually - gets better maintenance than the grid.]

We are planning on having the majority of our electricity come from solar panels when we end up in Nevada - mainly to keep the cost of refrigerating my space down =)

Where I am in Oz, heat pump (aka reverse cycle air con) is ubiquitous and has been for decades. So much so that the price premium for moving heat both direction versus one (cooling) is pretty marginal. How one installs it depends on the house. My house has a flat roof and zero space for ducting, so I just went with a split system per room. This is very cost effective. Multi-split systems, where there is one outside unit, come at a significant premium, but are needed if you are constrained by rules that only permit a single outdoor unit. More traditional houses go ducted.

I spent change out of $20k Aus - say $15k US (at the then exchange rate) to do the house. (A lot of the price was installation, I had a lot of electrical work done.) It is silly good. Just the downstairs area system will keep the entire house warm. But it is rare for the coldest part of the day on coldest day to get to freezing here. Summer is the problem, where 45C is the occasional unwelcome visitor, and some summers can run a solid week of over 40C with minimums of 30C at dawn. With solar panels aircon is free.

As always, how well insulated the house is makes a huge difference. But here the temperature extremes stay within the working envelope of heat pumps reasonably well. Just getting towards the edge on the worst summers days. So efficiencies are always pretty good. 3:1 is a good working number, and some units manage closer to 5:1, which is ridiculously good.