If your new-build home comes with a heat pump rather than a gas boiler, most of what you need to know is genuinely good news: it’s been designed into the house from the start rather than bolted onto an old system, which tends to work far better than a retrofit. There is one thing worth checking before you complete, though, that most buyers never think to ask about.
At a glance
- Better by design: a new-build heat pump is sized for the house’s actual insulation and airtightness, not guessed at like many retrofits.
- Different feel: often paired with underfloor heating and run at a steady low setting rather than the on/off blasts of a gas boiler.
- Check before completion: NHBC warranty cover for the heat pump depends on it having valid MCS certification, something developers sometimes overlook.
- Cover gap: mechanical issues are typically the developer’s responsibility only in years 1–2; years 3–10 cover structural defects, not heating systems.
Why new-build heat pumps tend to work better than retrofits
A heat pump added to an older home has to work with whatever insulation, airtightness, and radiators already exist, which is why sizing a retrofit correctly takes real skill. A new build doesn’t have that problem: the heat pump, the insulation, and often the underfloor heating are all specified together against the actual, known heat loss of the house, using a heating system designed for a heat pump’s ideal low flow temperature from day one rather than compromising around existing radiators.
How it actually feels living with it
The biggest adjustment for anyone used to a gas boiler is how a heat pump is meant to be run. Rather than switching on to blast the house warm and then off again, it works best left on a steady, low setting that keeps the house at a consistent temperature, particularly if it’s paired with underfloor heating, which responds more slowly and evenly than a radiator ever does. It’s a genuinely different feel day to day: gentler, less noticeable, and less prone to the temperature swings a boiler on a timer produces. Worth being aware of too: the outdoor unit does make some noise, so it’s reasonable to ask where it’s sited relative to bedroom windows, and the hot water cylinder needs airing-cupboard-sized space that a combi boiler home wouldn’t have needed to find room for.
The warranty gap most buyers don’t check
This is the part worth genuinely paying attention to before you complete. NHBC’s Buildmark warranty splits into two very different periods: years 1 and 2 are the developer’s responsibility for all defects, cosmetic included, with NHBC as a backstop; years 3 to 10 narrow down to structural defects only, foundations, load-bearing elements, and weatherproofing, not mechanical systems like a heat pump. So a heat pump fault showing up in year 4 generally isn’t something the structural warranty covers at all.
On top of that, NHBC cover for the heat pump in the first place depends on it having valid MCS certification confirming it was properly assessed. It’s an easy thing for a developer to overlook, particularly because new-build heat pumps don’t qualify for the old Renewable Heat Incentive scheme, which has led some builders to wrongly assume MCS certification isn’t needed for a new build at all. Before you complete, it’s worth simply asking the developer for the heat pump’s MCS certificate and its commissioning documentation. If they can’t produce either, that’s worth pushing on, since without it you may have no proper warranty backstop on the heat pump at all, structural or otherwise.
What it means for running costs
The government’s own projections for homes built to the Future Homes Standard estimate running-cost savings of more than £1,000 a year for a typical semi-detached home compared with the previous building standard, covered in more detail in our Future Homes Standard explainer. That’s a projection based on typical usage, though, not a guarantee for any individual household, and your actual bill depends heavily on your electricity tariff. Since a heat pump shifts your energy use from gas to electricity, it’s worth checking our guide to electricity tariffs for heat pump owners once you’ve moved in, since the right tariff can make a meaningful difference to what those projected savings actually look like on your bill.
Should I ask to see the heat pump’s MCS certificate before completing?
Yes. It’s a reasonable, normal question to ask, and without it the heat pump may not be properly covered under your NHBC warranty.
Is it normal for a heat pump to run constantly rather than switch off?
Yes, running at a steady low setting is normal and is generally how heat pumps operate most efficiently, unlike a gas boiler’s on/off pattern.
What happens if the heat pump develops a fault after year 2?
The NHBC structural warranty for years 3 to 10 generally doesn’t cover mechanical systems like heat pumps, so you’d typically be relying on the heat pump manufacturer’s own warranty at that point rather than NHBC.
Will my running costs definitely be lower than a gas-heated home?
Likely, but not guaranteed for every household. It depends on your electricity tariff and usage pattern, so it’s worth reviewing your tariff options once you’ve moved in.
Final thoughts
A heat pump in a new build is a genuinely different, and usually better, experience than one bolted onto an older house, precisely because it was designed alongside everything else rather than compromised around it. The one thing worth doing before you complete that most buyers skip: ask for the MCS certificate and commissioning paperwork, since that single document is what actually determines whether you have a proper warranty backstop on the heating system for years to come.