The thing is, heat pumps aren't a particularly good deal right now.
Heat pumps generally have less heat output than a gas boiler, so it won't make your house any warmer.
Even taking government subsidies into account, the installation costs are several times higher than a gas boiler, both for the unit and often requiring new radiators and suchlike.
And typical energy prices in the UK might be 6.5p/kWh for gas, 26.0p/kWh for electricity - so even if your heat pump achieves a 3.0 CoP your running costs are still higher. In the UK, the months when you'll want the most heating are the months when domestic solar output will be at its lowest. To make savings you've got to switch to a plan where electricity costs change several times a day, such as https://octopus.energy/smart/cosy-octopus/ and not run your heating between 16:00 - 19:00. This makes a well-insulated home even more important.
And you might think you're going to save money by not paying the gas supply 'standing charge' - but gas suppliers can charge whatever they like to remove your meter. If they say it's £1500 to remove your gas meter and save you 30p/day - you're probably not going to be saving 30p/day
So it's less a case of "investing" in the house, and more a case of "investing" in good karma by helping the environment.
Cool! I hope I didn't come across as hating the technology. In a perfect world I hope we'd be using geothermal district heating but while we're still installing units in individual homes I think heat pumps are currently the best way forward. The economics of retrofitting many standard homes simply don't really line up in many cases. Prior to the current energy crisis they were generally more costly than using gas and even after they only really make economic sense for the relatively small number of people stuck on electric heating[0].
Home renewables help but require even more capital investment, often taking 10 or more years to pay off. It doesn't help that where I am solar has extremely limited output in the winter. Domestic wind turbines are difficult to situate and get planning approval for. My cursory impression is that they're also less economical than many solar installs.
I've got some roof repairs coming up soon and I'm hoping the economics of replacing the existing roof with some nice looking solar slate tiles work out favourably!
I'm in the UK. Our gas is metered in m^3 but our energy suppliers typically bill and advertise based on the converted kWh price. My current prices for electricity and gas are 33.76p/kWh and 10.28p/kWh respectively. That's after a government price cap has been applied without it it's 49.15p/kWh and 14.00p/kWh
Based on those prices a heat pump would need to have at least an efficiency of 3.28 (3.5 uncapped) just to break even. Given that the total cost of installation is in the range of £3k-40k there really needs to be a compelling reason to retrofit an existing house.
Some of this is due to the vagaries of the UK energy markets. The outcome is that we often end up paying renewable providers of electricity based on the cost set by gas powered stations. At the moment that price has been grossly inflated due to profiteering, we're far less reliant on imported gas than mainland Europe.
I'd like to note that the price savings and break even point have probably gotten better compared to when I last checked. If we go back to much warmer, happier times - like September 2020 - I was paying 15.999p/kWh and 2.915p/kWh for electricity and gas respectively. Prior to that it was 14.150p/kWh and 2.920p/kWh. At that point I believe an air source pump resulted in a net increase in my bill and a ground source heat pump would have taken around 30 years to pay off. I should probably recalculate when things have settled down a bit.
This is as zero-emission as the grid, simply having someone else burn fossil fuels doesn't make it clean (it's probably better but still).
Also gas is a lot cheaper to heat with at current UK prices than electricity. One of the reasons heat pumps are used is that the increased efficiency offsets that.
Probably more significantly: about 30-40% of UK energy use is gas central heating which is 90-95% efficient. Electric heat pumps (beginning to be installed in numbers the U.K.) are 300-400% efficient.
I am extremely sceptical of this claim. I have had a heat pump installed in November (UK), and my estimates from over the winter is that it cost me less to run than my (admittedly old and inefficient) gas boiler. As it was probably past time to replace the boiler, it would not have been a bad move even without government incentives. The incentives made it a no-brainer. My house is reasonably well insulated as the previous owner did do that upgrade, and that might be a necessary first step before switching to a heat pump. Even on gas, though, you will save a lot by upgrading the insulation.
In the UK it's more pronounced. I pay £0.28/kWh for electricity and £0.069/kWh for gas, so as I understand it installing a heat pump will end up increasing my energy bills unless its coefficient of performance is over 4.
Even with the government grant taken into account it would cost me £3,000 to have a heat pump installed at my house. The running costs would be around £500-600 a year more than I'm paying to heat my home with gas at present, and that's with my gas bill having almost trebled over the last year and a bit. Financially, as things stand, it would be lunacy for me to scrap the gas boiler in favour of a heat pump.
Where do you get your numbers from? Right now, pre heat pump, I'm at 2000kWh usage and return to the net 4000kWh (so 2000kWh in excess). I use 750m3 of gas.
This costs me 100e per month.
I'm investing in a full electric ground source heat pump. Which cost me 20k. An alternative is a air heatpump which is around 8k, but with a lower scop.
Let's assume a scop of 5 (air-air) which is conservative. The amount of energy required for heating / showering / cooking was 750 * 9.27 = 6952.5 kWh. Dividing this by the scop of 5 means I require 1390.5 kWh to replace gas. This means I still have excess of solar kWh.
For now I can use the grid as a battery. This means I have no electricity costs - I actually get 20e per month after taxes.
So for 8k I have nullified my gas and electric bill. This means a payback period of 5.5 years (8000/120/12) or a yield of 18% (120/8000 * 100*12) per year.
So it isn't required to have tens of thousands to invest and you get a positive yield (depending the tax climate) even with current gas prices.
The 20k ground source heat pump looks a bit different. But I like that it is quiet and it can cool in summer for less energy that an air-air one.*
If we want to move the needle in a meaningful way (CO2 wise), heat pumps and solar panels need to get better, cheaper, easier to install, and more available.
Where I live, driving a heat pump is more expensive than burning gas, from a purely economical POV. Our cost ratio per kW/h for electricity:gas is 3.5:1 right now, but COP for consumer heat pumps in real-world usage is just 2.6 (Yeah they all claim a COP of at least 3, but those are as realistic as ICE fuel economy ratings.) Those ratios need to at least match in order for a heat pump to make any kind of financial sense.
Those heat pumps for a mid sized house cost €15k right now. On back order for 12+ months.
Yeah, I did the maths with a heat pump drier and found it would pay for itself in electricity savings in a couple of years. And that was before the cost of electricity in the UK tripled. It uses something like 1/4 of the electricity per load, and because it's unvented all the heat remains in the building envelope.
Isn’t the main problem the cost of heating? In the UK at least a kWh of electricity cost 4 times what a kWh of gas costs. Even if a heat pump is twice as efficient as gas heating, the cost of heating is still twice as high.
Meanwhile it was estimated that half of Swedish houses were equipped with heat pumps in 2016. That number has certainly not gone down since given the steep rise in electricity costs we’ve had since. Many houses have been converted from horribly inefficient direct electric heating to heat pumps.
I suppose this would be true if gas is expensive where you live. It's really cheap here, our heating bill is like $80/mo in the coldest of months for a 3k sq ft house. A heat pump even with the efficiency gains would be on par with that (unless we jumped into solar, which I have considered).
It isn't great, but perhaps surprisingly so using gas to create electricity and the electricity for a heat pump, is still a lot better than using a regular gas boiler. In other words, you'll get more heat out of a m3 of gas when you use it to create electricity and power a heat pump with the generated electricity, generally speaking.
So it is an improvement even if the net is 100% dirty. But it isn't, even in winter we can get a lot of electricity from renewable sources.
I think there are two big issues with heat pumps: they are expensive and require well insulated homes. Both problems can be solved.
Before: Jan 600kWh electricity, 3300kWh gas = 3900kWh
After: Jan 1580 kWh electricity, 20kWh gas (cooking hob)
So in total, 41% of previous amount, and for heating, 30%.
So yes, for crappy uk houses heat pumps are totally fine.
Adding in solar pv, and a time shifting battery, and the bills are maybe £2k per year lower than they would be.
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