Hello all, I’m keen to seek opinions on installing a heat pump for my heating and hot water. I currently live in an old (pre 1800) house in a rural location where we don’t get mains gas, so currently have an oil tank and boiler, while using mains electricity for everything else (EV charger, cooker etc).
With recent events, the price of oil has already more than doubled and in all likelihood will only get worse. Not a great fan of being beholden to outside forces to such an extent. So my option is to switch to a heat pump and run solely on electric. There’s a decent government grant which should cover about 2/3rds the cost of the system itself, and I already have a well functioning water tank currently heated by the oil burner which our supplier thinks we could just switch over.
BUT, my dear old house is large and drafty. There’s no chance of wall insulation (solid stone walls), we have large windows (double glazed) and have done what we can with roof insulation. I’m already aware I might need to upgrade the radiators to larger models. I’ve been told that you ideally need a ‘stable’ environment - ie a well insulated house - for it to work most effectively, but that’s just not an option here.
Being all electric obviously has its own challenges, but currently power-outs are very rare and there’s a big move in the UK towards renewables, and our boiler needs electric to fire up anyway.
Anybody had a similar experience or have any good advice? BTW I’ve already had a quote for solar panels and battery, but the savings on that would take 15 years to recoup installation costs, and I don’t imagine we’ll stay here that long - we plan to downsize in about 10 years’ time.
Probably worth adding that where I live is a temperate climate - rarely falling below 26°F in winter or exceeding 79°F in summer, so no need for aircon. I also have a large wood burner I use on winter evenings for a cosy living room.
Do you know if there are free or low cost energy audits available in your area? They will send someone over with an IR camera and assess where the heat is leaking out of your house and what the most cost efficient fixes are. Some of them can also do computer modeling to tell you what sized heat pump you actually need.
There’s also the possibility of only well insulating certain rooms in your house and retreating into those when the weather gets bad.
We went with minisplits for our heat and kept the furnace as a back up and to pull the heavy load at low temperatures and if needed quick warmups. It has worked well for us.
Being the UK, sounds like hot water boiler and radiators. What kind of radiators? Big old cast iron ones, newer flat panel radiators, or slimline baseboards? I don’t think any of those are the best fit for a heat pump. Replacing them to make a heat pump work would also be a bad investment. I’d try to make mini splits work.
Easier than replacing all the radiators in a home, or trying to do through-wall units. It’s just drilling some holes. There is the aesthetic consideration of having a big box on the wall of every room, difficulty covering smaller spaces like bathrooms or hallways, and the need to run electricity where it might not already be convenient, but those are not necessarily insurmountable.
Another concern is that many tax breaks require the old system to be removed, so if you want to keep that as a backup then you lose the incentive. The advantage here is that the climate doesn’t get super cold, so you’re not fighting both the poor insulation and decreasing capacity to the extent you would in more extreme climates.
My hot water radiators are not compatible with using current heat pumps, because they depend on the water being very hot, and heat pumps work best over a small temperature gradient. But the HVAC guy who told me that said that some European radiators use water at a lower temp and can be used with heat pumps.
Yes I think that’s right, a client of mine is a national home builder, installing heat pumps now in all their new properties, and they’re still using hot water radiators - some of the ones in smaller rooms look a fair bit thicker/deeper than normal ones though.
I also live in an old house, but with an east/west roof, the payback for fitting solar would be ten years or more. At my age, that’s not a sound investment.
You describe your house as “draughty”, so that’s one area you could investigate and cure. Closing off unused bedrooms can save on heating too.
We installed a Mitsubishi Hyper Heat mini split a couple of years ago. I kept the gas fired boiler, and I switch between the heat sources depending mainly on how much of the house I want to heat and the temp outside. We mostly got this for two reasons:
-We have a finished basement which is on the first floor zone, and it was always cold down there
-Air conditioning!
What I can tell you is that we’re thrilled with it, and the amount of heat it pumps out will cook you out of the room no matter how cold it is outside, at least for as cold as it gets near Boston, and we just had one of the coldest winters in a long time, getting to overnight lows of around zero F / -18C for a few weeks. I could not believe how much heat they make.
For strictly money reasons, we’re finding they work best down to somewhere in the 20s F, after which while they work fine, they get more expensive than the gas. So we run the heat that makes sense for the conditions.
And in summer, even though only about 1/2 the house is fitted with the splits, they can keep the whole house comfortable as long as you’re willing to leave interior doors open.
I know your question was about a drafty old house, but I’m pretty confident that these things would keep up even if I left half the windows open.
Possibly not applicable where you are, but we tried applying through a program available here. This house did qualify for a batch of additional insulation; they did that, then ran a pressure test. Pressure test still came out so leaky (1800’s windows) that we didn’t qualify for the heat pump grant; they said it wouldn’t work well enough.
You’re warmer there, and any grants available may work differently.