The short answer
There is no single best heat pump for an old house — the right choice depends on the property's heat loss, not the badge. That said, older, solid-wall and period homes usually benefit from a high-temperature air source heat pump, often using R290 refrigerant, which can reach flow temperatures of around 60-70°C. That lets the system keep more of the existing radiators and reduces how much fabric upgrading is needed. The far more important factors are insulation, draught-proofing and correctly sized radiators: a heat pump in an old house works best when heat loss is reduced first and emitters are sized for low-temperature operation. An MCS-certified installer's heat loss survey is the deciding step — it sizes the unit, identifies which radiators to upsize, and confirms whether a full or hybrid system suits. Done properly, heat pumps heat old homes effectively across the UK.
Older homes are often said to be unsuitable for heat pumps. In reality, the right unit and a properly designed system make them work — the key is matching the heat pump to the property and reducing heat loss first. Here is how to approach it.
Heat pump for an old house
- Best unit typeOften high-temperature ASHP (R290)
- Typical high-temp flowAround 60–70°C
- First priorityInsulation and draught-proofing
- Second priorityCorrectly sized radiators
- Deciding stepMCS heat loss survey
Why old houses need a different approach
Older properties — solid-wall Victorian terraces, period cottages, pre-war semis — tend to lose heat faster than modern homes. A standard low-temperature heat pump can still heat them, but only if the radiators are large enough to release sufficient heat at low flow temperatures, which may mean upsizing many of them.
A high-temperature heat pump, often using R290 refrigerant, can produce hotter water — flow temperatures around 60-70°C in some models. This lets the system keep more existing radiators and behave more like the gas boiler it replaces, which simplifies the retrofit in a property where extensive radiator changes would be costly or impractical. The trade-off is that running at higher flow temperatures reduces efficiency, so it is a balance between retrofit cost and running cost.
| Approach | What it suits | Trade-off |
|---|---|---|
| Standard low-temp ASHP | Insulated or upgraded old homes | May need many radiators upsized |
| High-temp ASHP (R290) | Solid-wall, hard-to-treat homes | Higher flow temp lowers efficiency |
| Hybrid (heat pump + boiler) | Very hard-to-treat homes | Keeps a fossil boiler; no grant |
| Insulation + low-temp ASHP | Most old homes, done properly | Up-front fabric work |
Indicative guidance for older properties. Sources: Energy Saving Trust; MCS; Nesta.
Insulation and radiators come first
The single biggest factor in a successful old-house heat pump is reducing heat loss before sizing the system. Loft insulation, draught-proofing, and where feasible solid-wall or floor insulation all lower the heat demand, which means a smaller, more efficient heat pump and lower running costs. These measures also help with comfort regardless of the heating system.
Radiator sizing is the next priority. Because heat pumps run cooler than boilers, the radiators must release enough heat at the lower flow temperature. A heat loss survey checks each room and identifies which radiators need to be larger. Many old homes need only a handful upsized; others need more. Underfloor heating on a renovated ground floor is an option where floors are being lifted anyway.
Listed buildings, planning and outdoor units
Older homes sometimes come with planning constraints that newer properties do not. Many air source heat pump installations in England fall under permitted development, but there are conditions on the size and siting of the outdoor unit, distance from boundaries, and noise. In conservation areas, and especially for listed buildings, permitted development rights can be restricted, and listed building consent may be needed for changes that affect the property's character — including where the outdoor unit and pipework are placed.
The outdoor unit needs a position with good airflow, away from being boxed in, and ideally not directly under a bedroom window of a neighbour. In a terraced period street, finding a discreet location with enough space can take some thought, but it is usually achievable. A wall-mounted or ground-standing position at the rear is common.
It is worth checking the local planning position early, particularly for listed or conservation-area properties, so the design accounts for any restrictions from the outset. A good installer will be familiar with the permitted-development conditions and can advise when consent is likely to be needed.
Realistic expectations and choosing the system
A well-designed heat pump will keep an old house warm, but it heats more steadily than a boiler — running for longer at a lower temperature rather than blasting heat in short bursts. Once set up correctly with weather compensation, this delivers consistent comfort and good efficiency.
For a genuinely hard-to-treat property where full electrification would need impractical upgrades, a hybrid system (heat pump plus a back-up boiler) can be a pragmatic stepping stone, though it keeps a fossil boiler and is generally not eligible for the £7,500 grant. For most old homes, the strongest result comes from improving insulation, sizing radiators correctly, and choosing an appropriate air source heat pump — high-temperature R290 where the fabric is hard to upgrade, standard low-temperature where it can be improved. The MCS installer's survey is what determines the best specific unit for your property.
Frequently asked questions
Can a heat pump heat a solid-wall Victorian house?
Yes, when the system is designed for it. A high-temperature air source heat pump (often using R290) can keep more existing radiators, and reducing heat loss through insulation and draught-proofing makes a big difference. An MCS heat loss survey sizes the unit and radiators correctly; done properly, heat pumps heat solid-wall and period homes effectively.
Do I need to insulate before getting a heat pump?
Reducing heat loss first is strongly recommended. Loft insulation and draught-proofing — and solid-wall or floor insulation where feasible — lower the heat demand, allowing a smaller, more efficient heat pump and lower running costs. The Boiler Upgrade Scheme also requires a valid EPC with no outstanding insulation recommendations, so some insulation work is often needed for grant eligibility.
Is a high-temperature heat pump better for an old house?
It can be, because it produces hotter water (around 60–70°C in some models) and so keeps more existing radiators, simplifying the retrofit in hard-to-treat homes. The downside is lower efficiency at higher flow temperatures. The best choice depends on whether the home's fabric can be upgraded — an MCS heat loss survey weighs retrofit cost against running cost to decide.
Sources & further reading
- Energy Saving Trust — air source heat pumps
- Nesta — making heat pumps work in older homes
- MCS — find an installer and heat loss surveys
Figures on this page are typical UK ranges drawn from published sources and depend on your specific home. They are guidance, not a quotation or guaranteed saving.