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!
Last time I checked, replacing an existing gas installation with a heat pump in the UK just wasn't economically sensible.
Air source heat pumps were barely breaking even compared to gas so you'd be spending £10k+ to install it without saving any money.
Ground source heat pumps offered better efficiency but if I recall correctly purchase + installation was a £35k investment that would take decades to recoup.
There's also the consideration of additional costs due to lower running temperature which often necessitate larger radiators.
They might make more financial sense if energy costs stay high, since they're easier to supplement with domestic renewables.
Electric heating isn't terribly viable as an option in the UK. An awful lot of our winter electricity comes from fossil fuel generation especially during cold winters when demand is highest, it's expensive and inefficient to convert gas to electricity and run that through a heater instead of burning it directly, and we're too temperate a climate for heat pumps to be viable except maybe on new builds. Also, electricity supplies to rural areas aren't terribly reliable during bad winter winter so it's probably not that suitable for heating.
We're supposed to be phasing out gas for new build homes in a few years but I'm not convinced it will actually happen.
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.
We have the same situation with gas powered heating in the UK. There is a push towards heat pumps, but they are often expensive up front and don’t always save money in the long term (although if gas prices skyrocket this would obviously change).
Quite expensive? That's understated. My understanding now is that it comes at the cost a modest new house.
Our family bought a house in the immediate periphery of a smaller city. Since most city housing here is old, the consequence of that decision is that our modest city home has abysmal energy efficiency.
I have wanted to renovate ever since we bought it, in order to cut down on our carbon footprint before 2030, but I have given up on the idea that we'll be able to afford a heat pump before then.
After having spoken with several architects, the building cost alone will eat up €200K without any frills. This will make our house smaller, by replacing poorly built annexes with a more compact and thus thermally efficient cube shaped annex. This comes on top of the mortgage that we took out.
So ironically, in making our home more energy efficient, we would also be making it smaller and less desirable in this regard, at a great expense. Tacking on a heat pump and PV panels would inflate the cost by another 10%.
That is the very real cost of making a home suitable for low energy heating systems.
Don't get me wrong, I'm counting my lucky stars that I'm able to consider such an undertaking, but going through this exercise myself is just a reality check of how dire the situation really is.
If we want to achieve net zero in housing, can we really do so at the cost of conventional building practices?
Talking about the local situation, less than a third of homes are from after 1981 [1]. That's millions of homes slated for a similarly-priced revamp. Who is going to foot the bill? Even with government incentives, some owners don't want to spend all that money on something as intangible as low energy housing, and others simply can't afford to.
The big cost is the upfront cost of insulation and removal the existing heating systems.
Speaking about the UK (article is mostly about he US which will have their own problems), we have very poor quality housing stock with effectively zero insulation. You hold your hand to the exterior walls of your typical 2-3 bedroom terrace house (the most common type of home in the UK) in the winter and its just ice cold. For these homes the exterior wall are just solid brick and plaster with no air gaps. Many homes still don't have double glazing and their windows bleed even more heat. These homes go cold quickly when you turn off a gas boiler, and a heat pump just cannot keep up with the heat loss.
In addition large numbers of households in the UK have migrated to "combiboilers" heating systems that dispensed with hot water tanks for on demand hot water from their gas boiler. In the process many of these properties have converted the space previously designated for hot water storage to loft extensions or other home upgrades. UK homes are pretty small, and going to a heat pump system means going back to hot water storage, which most UK homes have no space for without costly changes to the home layout/structure potentially including sacrificing parts of precious loft conversions.
Frankly we might be better off just knocking down and rebuilding some of our housing stock at higher densities such is the cost of retrofitting and our housing shortages, but there is no political appetite in the UK for any radical solutions like that.
Of course, mechanical ventilation and heat recovery helps. I had it in my last place which was a new build. But now you're saying on top of the wall insulation and heat pump, I also have to spend £10k on a MVHR system? My heating bill is only around £1200/yr - I'll never see that all money back even if it reduced my costs to nothing.
The reason costs are high is partially because costs have gone up a lot lately, and I'm in London. Even a new garden fence is going to cost me around £5k. But also, my house would need to have a brick cladding put on after the insulation to get it past planning. There would also be a lot of remedial work required before installing the insulation, such as removing the existing pebbledash render. And I don't even have asbestos to worry about (as far as I know), unlike a lot of other properties of similar age.
I agree we're a long way off net zero, but don't you think spending all this money on marginal improvements to old houses would be better spent on the generation side of things? Personally I can't see a future in the UK that doesn't involve some kind of hydrogen or synthetic natgas generation. We're going to need to solve the generation side anyway.
I had district heating which I had in my last place, which was great and had the footprint and plumbing was comparable to that of a regular gas boiler.
Possibly-relatedly, I'm in the process of getting some retrofit work done on my house to improve its insulation and reduce the carbon costs of heating it. I absolutely had not appreciated that a place like this, an 80s brick-built terraced house in southern England, could be responsible for 3.4 tonnes of CO2 emissions per year in heating costs alone.
The necessary retrofit work is expensive, on the order of £50'000 over the next ten years, which makes it pretty much out of reach for the huge majority of people in the UK, but will take that down to 0.2 tonnes/year (narrowly missing net-zero because of the concrete-slab construction of the floor). We really need to be subsidising retrofit work like this, so that ordinary people can afford to have it done, because it makes a huge difference to what must be millions of similar houses in the UK alone.
That's the sort of change I had in mind. To start a move off fossil and onto electric utilising community heat pump schemes for new estates and apartments etc. Far better as a community thing than individuals so the costs are reduced to each. That or electric for those houses with solar.
Definitely. As a smallish mid terrace, our house has very little exterior wall space that isn’t already taken up with doors and windows. Air source heat pumps are being pushed by people with well insulated semi or fully detached houses with space for a tank and who have the cash to splash on the work that would be needed to replace a compact combi boiler.
If someone can work out a more compact system that could perhaps go in our loft then that might work, but that would probably require roofing work to accommodate the largish ducting that you would need.
I’m all in favour of decarbonising, but it needs to take into account how mostbof is actually live. For example, I’d love an electric car, but we don’t have off street parking, so can’t guarantee charging up overnight.
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.
Also had a look at electrical heating options again recently. Everywhere I've lived that burns fossil fuels to generate heat has been plagued by costly maintenance. At my current place, not unique to these issues, I've now spent an average of £175 a year on repairs (£1230 total over 7 years). In contrast, I lived for 10 years in a place with electrical heating and never had to do any maintenance whatsoever. Certainly gas is cheaper to run in terms of the price per unit of energy consumed, but if you factor in the maintenance and the hassle factor of taking time off to be in for the repair people, then I'm not convinced there's such a big difference. If you ask a boiler repair person about switching to electricity though, they'll say they strongly recommend against it, but part of me wonders if that's because they have a vested interest in keeping people using the high maintenance options. I used to joke that the only reliable thing about my boiler was the revenue stream it generated for the repair people.
Underfloor electrical heating is apparently a lot more efficient than radiators, e.g. because you only need to run them at a much lower temperature. If you combine with things like ground source heat pumps and solar panels, the electric heating proposition looks a lot more appealing.
That said, the conclusion I came to is that for an old place that doesn't otherwise need major work, it just isn't worth the expense of making the switch. It might be that if I were to move somewhere that needed a complete refurbishment anyway, then I would. Even then, with most homes, at least in cities like London, being flats rather than houses, then things like solar panels and heat pumps become much more difficult if not impossible to arrange.
Electric heating via heat pump is ridiculously efficient and has a much bigger bang for your carbon-reducing buck than anything else a homeowner can do.
It always baffles me to see how the rest of the world seems oblivious to modern heat pumps. They come in a variety of medium (air-air, air-water, geothermal-water). Seeing how heating a house is the biggest energy expenditure it should be a no-brained to heat homes with heat pumps.
To give a concrete example, In Northern Sweden, above the Arctic line, a modern geothermal heat pump an warm a 200 m2 (~2000 sq feet) house for a year, including warm water, for 15000kWh. Using gas, the need would be 4x higher. Even if you use electricy made from coal, you’re still coming out ahead.
I believe the idea is that it solves two problems simultaneously, using excess wind when it’s available and making our domestic gas supplies “greener”.
The vast majority of uk homes have gas powered central heating (hot water radiators), there is no good route forward to upgrade/replace all of this infrastructure to make it “green”. You can’t economically run a hot water central heating system using an electric heat pump, the required temperatures are too high, so you either need to rip it out and replace the whole system with a modern one or at least either replace all the radiators with underfloor heating or masive wall mounted radiators (very expensive for the 10s millions of homes, this isn’t just a new boiler).
A hybrid hydrogen/natural gas or synthetic gas is a way to go green but keep the existing infrastructure either with a new boiler or hopefully minor component changes.
So while it may not technically be “best usage” in the academic sense, it could be argued that it is a sensible use economically for the UK.
I'm all for subsidizing heat pumps in addition to insulation. UK is wasting a lot of energy on single-glazed windows, and 100-year-old walls and roofs.
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.
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!
[0] https://www.statista.com/statistics/426988/united-kingdom-uk...
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