Is My Home Suitable for a Heat Pump? How to Check

The single biggest factor in whether your home is ready for a heat pump is whether your heating system can work efficiently at low flow temperatures. This is the root cause of most heat pump problems, and it's worth spending time understanding.

A gas boiler sends hot water to your radiators at 65–75°C. A heat pump works most efficiently at 35–45°C. At lower flow temperatures, the heat pump's efficiency (SCOP) is significantly higher — the difference between 35°C and 55°C flow temperature can mean a SCOP of 4.0 versus 2.5, which is the difference between running costs matching gas and running costs being significantly higher.

The problem: a radiator designed for 75°C water will put out much less heat at 45°C. The amount of heat a radiator emits scales roughly with the difference between the radiator water temperature and the room temperature. If you drop the water temperature by 30°C, you roughly halve the heat output.

This means a house with undersized radiators will struggle to stay warm at low flow temperatures — especially during the coldest weeks of winter. The solution is either to run the heat pump at higher flow temperatures (which reduces efficiency) or to upgrade to larger radiators (which adds cost but preserves efficiency).

A good installer will calculate the heat output needed per room and assess whether your existing radiators are large enough at 45°C flow temperature. If they're not, they'll tell you which rooms need upgrading. This is a standard part of a proper heat pump survey — if an installer quotes you without doing this calculation, find a different installer.

The better insulated your home, the lower its heat demand, and the smaller (and cheaper) the heat pump it needs. More importantly, good insulation allows the heat pump to maintain comfortable temperatures even in cold weather without running at high output for long periods.

Check these first:

• Loft insulation. You should have at least 270mm of mineral wool insulation in your loft. If you have less — or none — this is the cheapest heat loss improvement you can make (typically £300–£600). It's also a BUS grant requirement: if your EPC flags missing loft insulation, you must install it before the grant can be claimed.
• Cavity wall insulation. Most UK homes built from 1920–1990 have an unfilled cavity between the inner and outer walls. Getting this filled costs £500–£1,500 and significantly reduces heat loss. Again, this is flagged on your EPC and is a BUS requirement if recommended.
• Solid wall insulation. Homes built before 1920 typically have solid walls with no cavity. These are harder and more expensive to insulate (internal or external dry-lining, costing £5,000–£20,000+). A heat pump can still work in a solid-wall house — it will just need to be larger and will run at higher output.
• Floor insulation. Less critical but still worth checking, especially for ground floors over a crawl space or uninsulated basement.

A heat pump installation requires space in two places:

• Outside — for the external unit. The unit is typically 0.8m wide, 1.0m tall, and 0.4m deep. It needs to be positioned with reasonable airflow around it and must sit at least 1 metre from any property boundary under permitted development rules. It needs to be reasonably accessible for servicing. A small rear yard can work — a completely paved urban terrace with no external space cannot.
• Inside — for the hot water cylinder. Most heat pump installations replace a combi boiler with a system that includes a hot water cylinder, typically 200–300 litres. This is about 1.8m tall and 0.5m in diameter. It usually goes in an airing cupboard, utility room, or garage. If you have absolutely no internal space, an air-to-air heat pump (which heats air directly rather than water) avoids this need — but you'll need a separate solution for hot water.

A heat pump draws a peak current of 10–16 amps for a typical home. Most UK homes have a standard single-phase 100-amp supply, which is more than enough. What matters is that your consumer unit (fusebox) has a spare circuit available or can be upgraded.

In some older properties — particularly rural homes that haven't had electrical work done recently — the supply capacity or the consumer unit may need upgrading. Your installer will identify this during their survey. Budget £500–£1,500 for a consumer unit upgrade if needed; a supply upgrade from your DNO can cost more.

Heat pumps work best in:

• Well-insulated modern homes (post-1990 builds, cavity wall insulation, good double glazing)
• Properties with underfloor heating — UFH runs happily at 35–40°C flow temperature and is ideal for heat pumps
• Off-gas-grid properties on oil, LPG, or electric storage heating — economics are much stronger
• Larger detached houses with good garden space — room for the external unit, space for a cylinder, less concern about neighbour proximity
• New builds — heat pumps are increasingly standard in new construction and are designed for heat pump operation from the outset

You may need to do some preparatory work before a heat pump makes sense:

• Uninsulated or poorly insulated homes — address loft and cavity wall insulation first. It's cheaper and will also reduce your heating bills with any system.
• Homes with very small radiators — budget for radiator upgrades in the coldest rooms at minimum (living room, master bedroom).
• Properties without an EPC or with an expired EPC — you'll need a current one for the BUS grant. An EPC survey costs £60–£120.

In most cases, installing an air source heat pump is permitted development — you don't need planning permission. The permitted development rules (as of 2026) require:

• The unit must be at least 1 metre from a property boundary
• No more than one heat pump per property
• The unit must not be installed on a wall or roof facing a road
• Noise levels must meet the MCS 020 standard — the permitted development rights require this to be demonstrated
• The property must not be a listed building (listed buildings require listed building consent)
• The property must not be in a conservation area (or if it is, installation is only permitted on the rear)

MCS 020 is the UK standard for heat pump noise. It uses a calculation to show that the unit won't exceed 42 dB at a neighbour's nearest habitable room. Your installer is responsible for running this calculation as part of their MCS certification process — it's not something you need to do yourself.

If you're in a conservation area or a listed building, you should contact your local planning authority before proceeding. Your installer can advise.