Heat pumps can't take the cold? Nordics debunk the myth

I think it does, and it seems to work because of a defrosting feature that earlier models didn't have. But I wouldn't say it does so very clearly. Unless I missed it.

2600 is dirt cheap even by Euro standards, trust me.

Here in Italy a single room split would cost you around 1k to 2.5-3k depending on the brand.

A whole house system you're probably looking at 10k and then some.

I got a quote in rural America for a single room minisplit, $10,300.

Absolutely bonkers.

$2600 is utter bullshit. I had several quotes for a 1000sf house, not a single one was under 16000 installed, after rebates. My payback period was going to be almost 20 years even against a medium efficiency gas furnace.

Half of my house was 8k, the other side I'm planning to install myself because I don't have that kind of money just waiting to be spent anymore.

Even the Diy mini splits, you're paying $600 to $1000 easily for just one single unit.

Paid $6700 in May to replace mine.

I don't think Geothermal makes much sense unless you live in one of the extremes, mainly the cold one, For example I an from Slovakia and I don't think the temperature here went under -20C in the last few years, I barely remember any days going under - 10C, so you would be paying quite a premium for a geothermal heat pump for rather marginal gains, it would certainly need quite a good analysis if the difference in performance would ever pay for the price difference, especially with better insulation and heat recuperation systems becoming mandatory.

There are also things like heat pump based driers now on the market btw.

Yeah similar in the UK. £3k for a single room mini split. £6k for a two room, etc. There's no way you're doing a whole house for less than bend-over money.

Wow that's really pricey. Here in Malaysia a 2 HP mini split with inverter costs roughly RM 2400 including installation (around $500).

Granted the average salary here is much lower but it's amazing how much the prices differ given that they all basically come from the same factory.

Electricity monopoly in the US = they can price gouge, and this is literally the only reason I installed a dual fuel system with a less efficient heat pump. The Eversource electricity price hikes last year probably would have meant I couldn't afford to heat my home in the worst parts of winter here in Massachusetts.

This is how policies are killing the planet. Socialize electric utilities, upgrade the electric grid, subsidize the use of electric heat pumps so they're actually affordable for all end users, and of course more people would adopt them.

As it is, I run my heat pump as much as I can, which is like 9 months a year. Better than only having gas heat at least.

What's your heat pump? I've been looking into them and I can't find one that's willing to say it works past about -15.

Can you just start saying "America" that way it includes south America and Central America, also?

Makes sense to me that they could theoretically work all the way down to near 0 kelvin, just depends on their efficiency. Just so long as there is heat to be had…

Also, not sure energy star really means much.

This is not a myth but a fact, heat pumps don't work at extreme cold temperatures.
What temperature exactly depends on the coolant used.

The efficiency also degrades at lower temperatures.

This is a random example of first hit I got on a heat pump.
https://heatnow.dk/produkt/altech-sirius-9-varmepumpe/

Notice the effect drops dramatically below -20 C°.

But this is a pump sold for the Scandinavian market, therefore it is of course designed to work at low temperatures. It doesn't state the minimum, but I'm guessing it would be around -40 C°. Which is very good compared top older models.

The heat pump I just had installed in SW Ontario hands over heating duty at -10C to the gas furnace

It's not that people think they don't work in the cold, it's that they are less suited for the areas or days of extreme cold.

It really depends on the type of heat pump. Air-sourced heat pumps generally don't produce heat below -30C and below -10C they generally lose enough efficiency that you're better off using electric baseboard heating.

It just comes from a fundamental misunderstanding of how the universe operates.

They say oh well it's cold outside so how can it make it warm inside? They say this because they have absolutely no understanding of where the concept of a temperature comes from. They think that if it's 10° outside then there is 10° of energy outside presumably out to some arbitrary distance, because some places are warmer, but they don't really think that bit through. They don't realise that's not how it works.

Feast your heart on this:

https://en.m.wikipedia.org/wiki/Chick_culling

Better than 15 birds in 5 fir trees.

Their feathers were fanned by a firey breeze

EVs work fine in cold weather. I live in Minnesota and drive an EV. It loses about 10-20% of the total range in the winter, but most of that appears to be from generating heat for the passengers.

The problem isn’t that EVs don’t work in the winter, it’s that their range gets significantly reduced. We had issues with people literally up and abandoning their vehicles because their batteries ran flat.

In these cases the issue is less that the range is lost, and more that with snowy and cold weather traffic gets unpredictable. You can end up in long queues and that’s where the issues start.

When I went on a work trip up in the far north I never saw a single EV. Asked my colleagues about it and none of them thought EVs particularly feasible as a primary vehicle.

All that said, EVs work great for most people most of the time.

Yes. Goddamn dinosaurs biding their time until we kill ourselves off, just to build a new golden age of dinosaurs

Birds aren't real.

Not correct for modern heat pumps. They work down to at least -40F without switching to creating heat.

Yeah it's a bit shitty right now.. I applied.. 2k with the 7.5k grant (so the bare cost is 9.5k!). Not cost effective but.. wanted to do my bit.

However, I couldn't go ahead, it just didn't make sense.

To get the grant all rooms must be heated, and the cost of required adaptation of my bathroom to add a radiator of the required size was somewhat eyewatering..
\ Heat pumps must not cool, otherwise they're not eligible, so I'm still on the hook for AC at some point (given how hot it's getting) which is stupid given they're basically the same tech.
\ Planning rules state that heat pumps are only permitted development within a very specific set of conditions, and because of the noise they make I would have to get planning permission at my own expense (and my neighbours already complain if we talk too loud so likelihood of actually getting it very low).

And, specific to the installer I was using (Octopus)..

They wanted to install a 1mx1m water tank. That won't fit in the airing cupboard (not even close) so they suggested the kitchen... making it difficult or impossible to open the back door..
\ Their heat pump (daikin) is about 2m wide. My house is only 7.5m wide, you take off 1m each side for the legal thing where heat pumps have to be 1m from the neighbours boundary, space for the door, some drainage.. the only position they could suggest was the middle of the back yard..

A heat pump will always generate a small amount of heat just from the compressor running, but most of the time that's a lot less energy than is being moved. As the outdoor temperature drops the delta between input and output air temp will decrease until the difference is entirely from generated heat in the compressor. Most designs would turn on extra resistive heating once the output temperature drops below your set target though. Modern designs are capable of moving a reasonable amount of heat even down to at least -25°C / -13°F now though.

It gets less effective, down to running at 100% and not moving heat. Heat pumps work by expanding a gas, which cools it. Since it's cold, the "heat" outside was the gas. Then the gas is taken inside and compressed, the gas heats up from the compression (since all the energy is squeezed into a smaller space, effectively speaking). Now that heat can be transferred to the colder air inside. So long as the expanded gas turns colder than the outside, it can absorb heat.

From a Google, common ones can go as low as - 25C, which means they are able to cool a gas to lower temps than that when expanded. There is still heat to get, even in -25C.

I can only talk for myself but I have a Nibe pump here in Sweden with air source outside pump and water heating system to radiators on the inside. Even down to -30° with really shitty windows it was enough heat for me to be comfortable. Though it did indeed use the supplementary resistive heating a bit it was still able to give me about a 200% efficiency during that period. Give a typical winter (usually around -5-10C but, as said can go down to -20C or -30C for a week or so) it still runs an average of about 300-400% efficiency.

One thing that happens is that the defrost cycle takes a longer time, so it spends less time heating the building

I have an air sourced heat pump and it gets to -35C for a few weeks at time here. When it's that cold it does produce heat but your breath is hotter. There's no point in running it as it just doesn't make any kind of useful heat. Below -10C the amount of heat it produces noticeably tapers off.

You either buy some portable electric heaters for those 2-3 weeks when it's necessary, or you get a heat pump that has resistive heating as a backup.

They are just AC units in reverse. The biggest effect humidity is going to have is on how much condensation is going to form on the exterior radiator. That'll form frost that'll have to be melted in a defrosting cycle. That'll decrease performance and efficacy. Low humidity should keep that to a minimum.

This is my first comment, but since it's my job might as well:

The fact that you need a well insulated house for a heat pump is absolutely not true. What you need is a house where the expected heat loss at the design temperature can be added to the house using low temperature heating such as in floor heating. You can live in a cardboard box for all intends and purposes, if you can keep your house warm with (loads of) 35-40C water you are fine. And you would be amazed how much heat in floor heating can provide when having tubes at 10cm heart to heart distance from each other. Your energy bill will be enormous, but it would be as well if you would burn gas in a stove.

Does insulation help? Obviously. The most energy efficient, sustainable and comfortable kWh of heat is the one you don't need. Is it a requirement? Absolutely not.

Source, ex aerospace engineer that advices and installs heat pumps for residential buildings

Edit: This might differ across the pond but in the Netherlands in floor heating is super common. In America I believe this is not so much the case? Not sure.

A standard furnace works by kicking on when heat drops below the set point

So does a heat pump, and you can get Air to Water heat pumps that work almost exactly as a furnace.

The most efficient heat pumps are constantly trickling a little heat at a time, rather than cycling on and off.

Our stoker wood pellet furnace does the same if possible, it can't go below 25% capacity, because it doesn't burn right at lower capacities. So at certain temperatures, it maintains a steady state, but at others it has to turn on and off. A heat pump can easily do whatever is more efficient.

PS:

Heat pumps are similar technology to fridges, which also turn on and off depending on needs.

what does insulation have to do with heat pumps?

heat energy is heat energy, where you get it from doesn't matter, if your house isn't well insulated the heat loss will be the same regardless what pumps in the heat.

It seems to me like you're describing the genetic problem of having an undersized heating system, not anything specific to heat pumps. I'm positive heat pumps exist that are equal in capacity to whatever furnace you have.

It does sound like in your case improving your house's insulation would be a better investment than installing a new heating system though.

comparison to electric furnaces. That has been widely known for years to be hilariously inefficient.

By this, I'm thinking you mean "electric resistance heating" - i.e an electric heater.

Electric resistance heat is 100% efficient. Heat pumps can easily be 200%+ efficient.

For those reading wondering if this guy knows what he's talking about, he says that electric furnaces are "hilariously inefficient". They were in fact the most efficient option before heat pumps - more efficient than the most efficient gas furnaces. Electricity is expensive, so depending on the situation, it may cost more than inefficiently burning super cheap gas, but calling electric heating "hilariously inefficient" demonstrates a severe lack of knowledge of the area. So, with that in mind, consider whether anything else claimed here is worth retaining.