We ditched our oil tank for an air source heat pump – two winters on, here's what it's really like
From how well to works to the effects on our energy bills
Committed home renovators David and Andrew Harrison-Colley (better known on Instagram as The Home Boys) are part of Ideal Home's new Open House contributors, sharing their thoughts on making a home together and living through the tricky parts. See the rest of their articles here.
When we moved in, there was a big oil tank in the garden. It sat in the corner we'd earmarked for a patio, next to the old outside loo, and it fed an oil boiler that was coming to the end of its life.
When the extension went in, both had to be dealt with. The boiler needed replacing anyway, so our builder priced two options: a new oil boiler, or an air source heat pump. Once the £7,500 Boiler Upgrade Scheme grant came off, there were only a few hundred pounds between them. That made it a fairly easy call.
Why we came off oil
It wasn't one big reason. We wanted the tank gone and the garden space back. The price of oil kept going up. And a heat pump felt like the more efficient, greener option for the long run, especially as we were about to double the size of the house.
Timing mattered too. The extension has underfloor heating across the whole ground floor – kitchen, dining, living area and shower room – so it made sense to put the heat pump in during the build rather than try to retrofit it later. The unit went where the old boiler used to be, tucked away in a corner of the garden. The tank went, the outside loo went, and that cleared the sunny spot that's now our patio.
If you're on oil now, the grant is worth a look. The standard amount is still £7,500, but homes in England and Wales that currently heat with oil or LPG can get £9,000 until 31 March 2027.
The radiators
This is the bit we'd tell anyone to plan for. A heat pump runs at lower temperatures than an oil boiler, so the radiators need to be bigger to give out the same heat. We ended up buying 13.
Six were for the new rooms upstairs in the extension: two low ones under the windows in each of the two bedrooms, one on the landing between them, and a tall one in the bathroom. The other seven replaced old radiators in the original cottage that would have needed changing anyway.
We went for Milano Windsor column radiators from Best Heating, and bought the lot in a Black Friday sale, well before we needed them. Column radiators give a bigger heat output, which is what we needed, and they suit an old cottage far better than flat panels would. So we got the output and a look that fits the house.
Downstairs in the extension there are no radiators at all. With underfloor heating under the terracotta, we got every bit of wall back in the kitchen and living space, and the room stays at an even, comfortable temperature. The terracotta seems to hang on to the heat for ages, a bit like a storage heater.
Living with it
The biggest change is how you use it. A heat pump takes longer to warm the house than our oil boiler did, so you don't blast it on and off. We leave it running and let the thermostat sit between 19°C and 23°C. It never gets cold and it never gets roasting. It's just quietly warm.
The unit outside is fairly quiet. We don't notice it. The pipes are a different story in the old part of the cottage. In the extension they're hidden in the floor and walls, but in the original house we couldn't dig up the old floors or bury everything in the walls the way you can in a new build, so some of the pipework is on the surface. You can hear the water moving through it. It's not loud, but it's there.
We're on the Cosy Octopus tariff, which has cheaper rates at set times of day and a peak between 4pm and 7pm. We don't do anything clever. We just use less during the peak.
What it costs
We'd love to give you a neat before-and-after figure, but we can't. The house is twice the size it was, and this is the first year it's been fully insulated now the structural work is finished. It wouldn't be a fair comparison.
What we can say is that, by our reckoning, our one electric bill now comes in under what the oil and electric bills would have added up to. Solar panels are on the maybe list, but we want to work out whether they'd actually pay for themselves first.
If you're thinking about it...
- Get both options priced. Once the grant came off, ours were only a few hundred pounds apart.
- Budget for radiators. Ours all needed to be bigger, and 13 of anything adds up. Buying in a sale helped.
- Think about the pipework, especially in an older house where you can't hide everything.
- Expect to change your habits. Low and steady, not on and off.
- Look at your tariff. Ours has cheaper hours built in, so we just ease off during the peak.
The oil tank's gone, there's a patio where it used to be, and the house has stayed warm through two winters on one bill. We're not complaining.
