Heat pumps for rented flats: what a landlord needs to check

The short answer for a flat

A heat pump suits a rented flat only when four things line up: somewhere to put the outdoor unit, space inside for a hot water cylinder, permission from whoever owns the building, and a unit small and quiet enough to meet the planning rules. If one fails, the flat is not a candidate. A flat that fails is not a failure of the landlord, it is a property type where a heat pump is harder.

This page covers flats you own, whether freehold within a converted building or leasehold in a block. If you let a whole house, read the cost guide and the running cost page instead.

Where the outdoor unit can go

The outdoor unit needs air round it, a fixed base or bracket, and a position that does not annoy a neighbour. In a flat, that usually means one of these:

• a ground-floor garden or patio you control
• a private balcony or terrace with enough free space
• a flat roof you own or have rights over
• an external wall bracket, if the structure and the owner allow it

The top-floor flat has roof access but may have no right to use the roof. The ground-floor flat may have a garden but sit close to neighbours’ windows. Neither position is better in general. Both need the same checks.

Pipes also have to run from the outdoor unit to the cylinder and radiators. A short, direct run is cheaper and loses less heat. A long run through shared hallways or voids can be impractical or need consent.

The planning rule for blocks of flats

Class G of the General Permitted Development Order sets the limits for air source heat pumps on domestic premises in England. For a block of flats, the rule is a compressor volume of no more than 0.6 cubic metres, compared with 1.5 cubic metres on a house. That is a small unit.

Reading the legislation on legislation.gov.uk, the main conditions are:

• one unit on a block of flats (a detached house may have two)
• nothing on a pitched roof
• nothing on a flat roof within 1 metre of its external edge
• no unit on a listed building or in its curtilage
• limits in conservation areas and World Heritage Sites for walls and units facing a highway
• the unit must be sited to minimise its effect on appearance and on the amenity of the area, and removed when no longer needed

The noise figure used for these installations is 37.0 dB(A) at the assessment position. Article 4 directions can remove these permitted development rights in some areas. The legislation is the starting point, not the last word. Ask the local planning authority before you commit, particularly for a converted building, and see the checklist for rentals.

Leasehold: consent comes before quotes

If you hold the flat on a lease, the freeholder or management company controls the structure, the roof, the external walls and the shared parts. Fitting an outdoor unit usually touches at least one of them.

Do this in order:

1. Read the lease for clauses on alterations, external fixtures, nuisance and shared parts.
2. Write to the freeholder or managing agent with a clear description of the equipment and where it goes.
3. Keep the reply, including any conditions or fees.
4. Only then collect quotes.

This site cannot say what your lease allows. Some leases are silent, some are strict, and some need a licence for alterations. A solicitor who knows leasehold property can read the clause in a short job. Check your mortgage terms as well, since a lender can have its own view on alterations.

Noise, neighbours and shared walls

Noise is where flats get difficult. Units sit near windows and balconies that belong to other people. The 37.0 dB(A) limit is set for neighbouring homes, and in a block there is often a window very close to any position you choose.

Two practical points: ask any installer to show you the noise assessment for the exact position, and pick a spot away from bedroom windows. A unit that meets the limit on paper but sits under a neighbour’s bedroom is a complaint waiting to happen.

Options other than a standard outdoor unit

Air-to-air heat pumps warm rooms with indoor units and need no wet radiators or cylinder. The Boiler Upgrade Scheme pays £2,500 for a residential air-to-air system that replaces existing heating, compared with £7,500 for air-to-water. They heat, they do not supply hot water, so you still need a separate way to heat water. Read air-to-air heat pumps for rentals for the trade-offs.

Exhaust-air and other flat-specific designs exist, but we have not verified their grant treatment or planning route, so this page does not cover them. If an installer proposes one, ask for the MCS certificate route and the planning position in writing.

Communal heating. If the building has one shared boiler or a heat network, you probably cannot replace your flat’s heating at all. See heat networks and ambient loops.

Where a flat makes the strongest case

The strongest case is a flat heated by electric storage heaters or panel heaters. A heat pump delivers roughly three units of heat for each unit of electricity, if it is well designed and run at a sensible flow temperature, instead of one for one. Against Ofgem’s cap rate of 26.32p per kWh of electricity, that matters.

The weakest case is a flat on a cheap mains gas boiler. Gas is 7.97p per kWh under the same cap. A heat pump with a seasonal performance factor of 3.0 turns 26.32p into roughly 8.8p per unit of heat, against about 8.9p for gas at 90% boiler efficiency. That is level, before standing charges, so the saving is thin to none for a gas flat unless performance is good. Read is a heat pump worth it for landlords before you decide.

The grant rule helps a little. The Boiler Upgrade Scheme can replace fossil fuel heating “such as oil, gas, electric or LPG”. Electric heating is on that list. One grant per property, landlords are eligible, the installer must be MCS certified, and the installer applies on your behalf.

Top floor or ground floor

	Ground-floor flat	Top-floor flat
Outdoor space	Often a garden or patio, but close to neighbours	Roof or balcony, but often not yours
Pipework	Short run if the unit is outside the kitchen	May be longer; ceilings are shared
Consent	Freeholder for external ground	Freeholder for roof or external wall
Planning	No pitched roof, listed and conservation limits	Flat roof 1 metre edge rule
Typical risk	Noise to neighbours’ windows	Roof rights and access

Mid-floor flats are the hardest, because they have no roof and no ground.

Shared houses and HMOs

A house in multiple occupation is not a flat, but landlords of shared houses ask the same questions, so here is the short version. Heat pump planning rules for a house apply, not the flat rules. Letting to several households brings extra duties of its own, and we have not verified the detail for this page. Ask the council’s housing team whether any licence conditions touch a heating change before you start. The blog has a separate guide for shared houses at heat pumps for an HMO.

When this is not the right answer

Do not pursue a heat pump for a flat if:

• the building has communal heating that you cannot leave
• there is no outdoor position that meets the planning conditions and the lease
• the freeholder refuses consent
• the flat has a modern gas boiler and good insulation, and a lower-cost route to EPC C exists

Insulation, draught-proofing and a heating controls upgrade often come first. If the flat is below EPC C, see EPC C 2030 and your heating choice for what is planned.

Next step

Run your flat through the landlord heat pump calculator to see whether the numbers make sense, then use the quote form if you want relevant independent firms to contact you. There is no charge to you and no obligation.