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Comment by mytailorisrich | Hacker News Reader

> The cost of a heat pump, plus installation, is typically between £7,000 and £13,000.

That's the problem. This is a huge cost, not only for the poorer.

We can use the magic money tree to install them 'for free' for lowest income households, but then who will pay for any repairs or replacement?

At some point we must have a path towards lower costs for heat pumps. If that's not possible then it means back to the drawing board because heat pumps are not viable. In fact, my take is that they are pushed because we're also have massive issues with electricity production and the grid, so instead of investing in that the government pushes the costs to households by encouraging to spend a fortune on heat pumps.

> Heat pump sceptics have argued that the UK’s housing stock is not suitable for electric heating

Odd to conflate electric heating and heat pumps...

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Heat pumps are “electric” but they are a lot more efficient than “electric” heating by resistance.

20 years ago people were starting to install geothermal heat pumps in upstate NY that used a buried coil as a heat sink. The cost was high and the lead time to get the coil drilled was long.

Back then the story was that an air source heat pump was more practical if you lived a few hundred miles south of here. The main selling point was that one system served as both a central A/C and heater so it delivered premium comfort, switching from one mode to the other automatically. If you live in, say, North Carolina, you probably really want central A/C so sharing the capital cost for both functions is efficient.

My understanding is that recently air source heat pumps have improved to the point where they are practical in cooler places. You’ve still got the issue that the A/C function is less necessary here (maybe I want A/C really bad for one really hot month every few summers) and the system as a whole has to be scaled for a large heating load. I know of some successful installations but I know of some that were less than successful. If you install some new gear sommetimes you get less than perfect results: we were some of the first Americans to install one of those tankless water heaters you sometimes see outside of an apartment in in an anime and for some reason it refuses to boot up for a few weeks in the spring every year.

It's not necessarily the heat pump, but the internal remodelling to fit larger rads/underfloor heating, and better insulation.

Fundamentally, after that you're using an energy source 3x as expensive as gas, so... any time the COP is less than 3 you're losing money. Oh, guess when you need the most heating? That's right, when it's cold. I don't give a flying what the COP at 10 C is, because waste heat from everyday activities keeps the house warm at that. I care about the COP at -2. On a becalmed day when the output of circa. 24 GW of wind capacity is < 1 GW. This absolutely happens.

> On a becalmed day when the output of circa. 24 GW of wind capacity is < 1 GW. This absolutely happens.

2040s things: "Sorry I cannot drive to work today as there is no wind since yesterday". ;)

For modern heat pumps (e.g. Daikin Altherma) the COP at -2c will be around 2.8-3. They operate down to -25c in heat pump mode, then automatically switch over to resistive heating.

I live in Lithuania (-20c and lower during winter is not uncommon) and almost all new houses have them. You can no longer use gas for heating in new builds. 3kW of solar generates more than enough power (with net metering) to run a heat pump over the course of a year for the average size house (150m2)

Heat pumps are the same technology as air conditioning, just with inputs and outputs hooked up in reverse. It's not magic, and there's over a half of century of experience in maintenance of AC units. Scaling up production and installed base of heat pumps will benefit from economies of scale, and make them cheaper to install and maintain.

UK can produce more wind energy than it needs. The grid needs more interconnects, but it's a solvable problem. I'm really annoyed when people say "the grid can't handle it!". 100 years ago it couldn't handle electric lighting, but we didn't stick to candles. We've built the grid to handle what it needed, and we'll expand it to handle more.

> back to the drawing board

And do what? We're already overdue for preventing the climate crisis, and need solutions yesterday. We can't wait for heating with unicorn farts.

The realistic options are either staying with gas boilers or switching to heat pumps. Gas is highly problematic from both environmental and geopolitical reasons, so we need to make heat pumps work.

> Odd to conflate electric heating and heat pumps.

There is an important efficiency distinction between heat pumps and resistive heating.

The grid can't handle the rising demand right now. Hence my comment about needed investment...

> who will pay for any repairs or replacement?

That's what nobody wants to hear about - that heat pumps are massively complicated technology not only expensive to purchase and install but also requiring regular maintenance, in particular also heat exchangers with the low diameters we've come to expect from modern heating equipment requiring decalcifiers and other consumables. I don't know about UK but let be assured in Germany it's as bad or even worse, with plumbers and other craftsmen lacking, energy prices very high (heat pumps, like any compressor, requiring lots of power), and the government sticking fingers into their ears, doing absolutely nothing but drafting completely unrealistic energy consumption projections. Switching to heat pumps would require tens of decades alone, not including the rebuilding or insulating of a large part of houses to make this even remotely effective, which isn't feasible due to interest rates, etc., etc.

Another solution is to increase people’s salaries… but what do I know.

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