"Heat pumps do not work in old houses" is the most repeated claim in UK home heating, and it is wrong as stated. The accurate version is: heat pumps work in old houses, but the installation has to be designed properly and it usually costs more than in a modern home.
What the evidence shows
Large UK field trials have installed heat pumps successfully in properties of every age, including solid wall Victorian terraces. The systems delivered comfortable temperatures. The differences were in cost of installation and running efficiency, not in whether they functioned.
The physics is simple: a heat pump can heat any house. The question is what flow temperature it needs to do so, and how much electricity that consumes.
The three things that decide it
1. Heat loss
An uninsulated solid wall house loses heat faster, so it needs more heat delivered per hour. That means either larger radiators or a higher flow temperature — and higher flow temperature means lower efficiency and higher bills.
A room-by-room heat loss calculation (MCS requires one) tells you exactly what your house needs. Any installer who quotes without doing this survey should be discounted.
2. Emitter size
This is usually the real cost driver in period homes. Old cast iron radiators are often surprisingly good — they have large surface areas and work well at lower temperatures. Small modern panel radiators fitted in the 1990s are usually the problem.
Expect to upgrade some radiators. In a typical Victorian terrace that might be 4-8 radiators at £300-£600 each fitted. Underfloor heating on a ground floor, where a floor is coming up anyway, is an excellent match for a heat pump.
3. Fabric improvements
You do not need to bring a Victorian house to new build standard. The high-value, lower-cost measures are:
- Loft insulation to 270mm — cheap, essential, and required for the Boiler Upgrade Scheme if flagged on your EPC
- Draught proofing — floors, sash windows, letterboxes. Very cheap, disproportionate effect
- Floor insulation where suspended timber floors are accessible
- Secondary glazing where listing rules prevent double glazing
Internal or external solid wall insulation is expensive and disruptive. It helps, but a heat pump is often viable without it if the emitters are sized correctly.
Realistic costs in a period property
| Item | Typical cost |
|---|---|
| Heat pump and installation | £9,000 - £16,000 |
| Radiator upgrades (4-8 units) | £1,500 - £4,000 |
| Hot water cylinder (if none) | £1,000 - £2,500 |
| Boiler Upgrade Scheme grant | -£7,500 |
Net cost commonly lands between £4,000 and £12,000 in an older home — higher than the modern-home figure, mainly because of emitter work.
When a heat pump is genuinely the wrong answer
- No space for a hot water cylinder and no willingness to lose a cupboard. This is the most common hard blocker in small terraces.
- No viable external unit location — nowhere with adequate airflow, or planning restrictions in a conservation area that cannot be resolved.
- Listed building consent refused for the external unit or pipework.
- You are not staying and cannot recover the emitter investment.
Noise is rarely the blocker people expect: modern units at a few metres are quieter than typical background street noise, and permitted development has specific distance and noise rules your installer must meet.
How to get a trustworthy answer for your house
Get quotes from at least three MCS installers and compare:
- The calculated heat loss figure in kW
- The design flow temperature — lower is better; under 50°C is a good sign
- Which specific radiators they say need upgrading, and why
- The predicted SCOP
- Whether they have done period properties before, with examples
If two installers give wildly different answers for the same house, the difference is almost always flow temperature. The cheaper quote that leaves your radiators alone will cost you more every winter.
Read next: heat pump vs gas boiler running costs and Boiler Upgrade Scheme eligibility.