Heat pumps in an old Cotswold stone house

Can a heat pump heat an old stone house?

Yes, in many cases. A heat pump works well at lower flow temperatures for longer hours. The key is to size it for the real heat loss of the house.

The installer should calculate the heat loss room by room. This shows the size of heat pump you need and which radiators must change. Ask for the calculation in writing.

Reduce heat loss first

Thick stone walls hold heat, but old houses often lose a lot through draughts, roofs and windows. Start with the simple steps below.

Old solid stone walls need to breathe. The wrong insulation, render or paint can trap damp. Take advice from someone who knows traditional buildings before you insulate walls.

• Draught-proof doors, windows and unused chimneys.
• Top up loft insulation where the roof allows it.
• Use secondary glazing or heavy curtains where you cannot change windows.
• Insulate pipes and the hot water cylinder.

Planning and listed buildings

Since 29 May 2025, an air source heat pump on a house in England is often permitted development. A detached house can have two units. Each outdoor unit must be 1.5 cubic metres or less and meet the MCS 020(a) noise standard.

Permitted development does not cover a unit in the curtilage of a listed building. You need planning permission, and listed building consent for work that affects the building's character.

In a conservation area, a unit on a wall or roof that faces a road needs permission. Many Cotswold towns and villages are conservation areas. Check your council's map.

Where the parts go

An air source heat pump needs an outdoor unit with free air flow, usually at the side or back of the house. Keep it away from bedroom windows and neighbours where you can.

Most systems need a hot water cylinder. In a cottage with a combi boiler, find space for one, such as an airing cupboard or loft room.

Pipes may need to be larger. In old houses with solid floors, ask how the installer will route them.

The grant and VAT

The Boiler Upgrade Scheme gives £7,500 for an air source or ground source heat pump. Homes heated by oil or LPG with no mains gas get £9,000 until 31 March 2027.

You must use an MCS-certified installer, who applies for you. Installing a heat pump in a home is zero-rated for VAT until 31 March 2027.

What it costs

See our heat pump cost guide for national and local figures. Old houses can cost more if many radiators or pipes must change.

Questions

Sources