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This article was last reviewed on 1 July 2026. Boiler Upgrade Scheme grant figures are correct at that date and will be updated if eligibility criteria change.
Heat pumps are becoming much more common in UK homes. The standard Boiler Upgrade Scheme grant of £7,500 is available for most homes replacing a gas boiler, and homes currently heated by oil or LPG can claim £9,000 - a temporary uplift available until 31 March 2027. More homeowners than ever are asking whether their property could work. The honest answer is that most homes can get a heat pump. But the right setup matters. This guide walks you through the key things to check and tells you exactly what OVO looks at during a free survey.
What makes a home suitable for a heat pump?
There is no single test for heat pump suitability. It’s a combination of factors that together determine whether a heat pump will work well and be cost effective in your home. Here are the main ones.
Insulation
A heat pump operates at a lower flow temperature than a gas boiler, typically running at 45 to 55 degrees rather than 65 to 70 degrees. This means it needs to run for longer to deliver the same level of warmth. In a well insulated home, that works efficiently. In a poorly insulated home, the heat escapes faster than the pump can replace it.
Good loft insulation and cavity or solid wall insulation make a significant difference. If your home has poor insulation, it does not mean a heat pump will not work, but you may need to address the insulation first to get the best performance and running costs.
Outdoor space
An air source heat pump needs an outdoor unit, similar in size to an air conditioning unit, mounted on an external wall or on the ground outside your home. It needs reasonable airflow around it and should not be positioned directly under a bedroom window or very close to a neighbour's window.
For most homes this is straightforward. The unit takes up roughly the same footprint as a washing machine. You don’t need a large garden.
Radiators
Heat pumps work best with larger radiators or underfloor heating because they deliver heat at a lower flow temperature. If your current radiators are the right size, they may be fine. If they are on the smaller side, some may need upgrading to larger ones.
OVO's survey includes a heat loss calculation for your home, which tells us exactly what radiator output is needed in each room. In many homes, only a few radiators need upgrading rather than all of them.
Hot water cylinder
Unlike a combi boiler, a heat pump needs a hot water cylinder to store heated water. If you already have a cylinder, it may be compatible. If you have a combi boiler with no cylinder, a new one will need to be installed as part of the project.
Electricity supply
A heat pump runs on electricity. Most modern homes have adequate electricity supply, but the installation team will check your existing setup and whether any upgrades are needed. For most domestic installations this is straightforward.
Quick suitability checker
Use this table to get a sense of how your home looks before booking a survey. Green means likely fine, amber means check needed, red means may need work first.
| Factor | Good sign | Check needed | May need work first |
|---|---|---|---|
| Insulation | Loft and cavity wall insulated | Loft only, no cavity | Solid walls, no insulation at all |
| Outdoor space | External wall with ground or wall space available | Limited space, close to boundary | No suitable external location |
| Radiators | Modern, larger radiators throughout | Mix of old and new sizes | Very small radiators throughout |
| Hot water | Existing hot water cylinder | No cylinder, combi boiler | No cylinder, limited space for one |
| Electrics | Modern consumer unit with spare capacity | Older fuse box | Significant upgrade likely needed |
| Property type | Detached or semi, post 1930s | Terraced, pre 1930s | Listed building or conservation area |
This is a guide only. OVO's free survey is the accurate way to assess your specific home.
Which homes are not suitable for heat pumps?
Very few homes are completely unsuitable. But some will need more work than others before a heat pump makes sense. Here are the main cases where it’s more complicated.
• Homes with very poor insulation and solid walls where insulation would be expensive or impractical to install. A heat pump can still work but running costs may be higher than expected.
• Flats where there is no suitable outdoor location for the unit, or where the lease restricts external modifications.
• Listed buildings where planning consent is required and may be refused.
• Homes with very small rooms and no space for a hot water cylinder.
Even in these cases it’s worth getting a survey. OVO will give you an honest assessment of what’s involved and whether it’s cost effective for your situation. If a heat pump isn’t right for your home right now, we’ll tell you.
Does my home need to be perfectly insulated?
No. This is one of the most common misconceptions about heat pumps. The UK housing stock is old and imperfect and heat pumps are installed successfully in older, less well insulated homes every day.
The key is the system design. A well designed heat pump system, with the right size unit, the right radiators, and the right flow temperature, can work efficiently in homes that are far from perfect. The Boiler Upgrade Scheme no longer requires you to have no outstanding insulation recommendations on your EPC before accessing the £7,500 grant, which means far more homes can now apply. OVO checks your eligibility as part of the free survey.
How is a heat pump suitability assessment done?
OVO's free survey is a home visit from a local heat pump engineer. Here is what they check.
| What we check | Why it matters |
|---|---|
| Heat loss calculation for every room | Tells us exactly how much heat output is needed and whether your radiators are adequate |
| Insulation levels | Affects system efficiency and running costs |
| Outdoor space and unit location | Confirms where the unit can be sited and whether any restrictions apply |
| Hot water cylinder size and location | Determines whether your existing cylinder is compatible or a new one is needed |
| Electrical supply and consumer unit | Confirms whether any electrical upgrades are needed |
| DNO requirements | For larger systems, checks whether a grid connection notification is needed |
The survey typically takes one to two hours. At the end you’ll receive a full system design and a fixed quote. There is no obligation to go ahead.
What happens if my home needs upgrades first?
OVO will tell you clearly what, if anything, needs addressing before installation. In many cases upgrades are minor, such as replacing two or three radiators, and are included in the installation quote.
If more significant work is needed, such as insulation improvements, OVO can advise on the best next steps and whether it is worth doing that work first or whether the heat pump will still deliver good results without it.
Frequently asked questions
Can a heat pump work in an older house?
Yes. Many older UK homes have successfully had heat pumps installed. The key is getting the system design right for the specific property, which is what OVO's free survey establishes. Older homes often benefit from some radiator upgrades but rarely need a complete overhaul.
Do I need underfloor heating for a heat pump?
No. Underfloor heating works very well with a heat pump because it runs at a low flow temperature, but it's not a requirement. Most heat pump installations in the UK use standard radiators. Some may need to be slightly larger than the ones they replace, but this is assessed during the survey.
What is a heat loss assessment?
A heat loss assessment is a calculation that works out how much heat your home loses through its walls, roof, windows, and floor. The result tells your installer what size heat pump is needed and whether your radiators are large enough to deliver the required output in each room. OVO carries this out as part of every free survey.
Can I get a heat pump if I have a combi boiler?
Yes, but you'll need a hot water cylinder installed as part of the project. A heat pump can't provide instant hot water on demand the way a combi boiler does. Instead it heats and stores water in a cylinder, which is then available when you need it. OVO includes cylinder supply and installation in your quote where needed.
How do I know if my radiators need upgrading?
You won't know until a heat loss assessment has been done. OVO's survey calculates exactly what output is needed in each room and compares it to what your existing radiators can deliver at heat pump flow temperatures. Where a radiator is too small, we'll include an upgrade in your quote.
Is there a grant available to help with the cost?
Yes. The Boiler Upgrade Scheme provides a £7,500 grant for air to water heat pumps in England and Wales. There is no longer a requirement to have no outstanding insulation recommendations on your EPC before applying. Homes currently heated by oil or LPG can claim an increased grant of £9,000 — this higher rate is available until 31 March 2027, so if that applies to you it is worth acting before that window closes. OVO handles the grant application on your behalf as part of the installation.
Book a free heat pump survey
The only way to know for certain whether your home is suitable is to have it assessed. OVO's free survey is a no obligation home visit from a local heat pump engineer. We'll check everything, give you an honest answer, and provide a fixed quote if your home's a good fit.