Can You Get a Heat Pump in a Flat?

A small flat does not get a proportionally small bill. An installation has fixed costs that do not shrink with the home: in 2025/26 the median Boiler Upgrade Scheme installation was £11,494 for a 4 to 6 kW heat pump against £12,686 for 8 to 10 kW, so the £7,500 grant covers about two thirds of a flat's heat pump rather than all of it. A flat is not always the cheapest home to heat, either. At three bedrooms and up a flat does have the lowest heat demand of any property of that size, but a 1 bed flat uses about 5,040 kWh a year against 3,870 kWh for a 1 bed mid terrace and 3,690 kWh for a 1 bed semi, and a 2 bed flat at 6,390 kWh sits just above a 2 bed mid terrace at 6,300 kWh.

Running cost is where it gets narrow. On standard electricity a 2 bed flat costs £605 a year against £566 on gas, £39 more, and every flat size lands the same way: £31 a year more at 1 bed, £48 more at 3 bed. On a heat pump tariff at about 18.7p it costs £430, which is £136 a year less than gas. At £4,300 out of pocket that would take about 32 years to pay back, well beyond the 20 years the government assumes a heat pump lasts (Boiler Upgrade Scheme impact assessment, 2022). If the boiler needs replacing anyway, the comparison is the extra over a new gas boiler, about £3,200 for a two bedroom home on our boiler comparison, which scales the DESNZ average of about £3,500 for a three bedroom home, so about £1,100 more, which the tariff saving pays back in about 8 years. On standard electricity there is no running-cost saving to pay anything back, so for a flat already heated by gas a heat pump tariff is a condition of the case rather than a bonus.

If your flat is not on gas the picture changes completely. Heating 6,390 kWh with direct electric heating at 26.32p/kWh costs about £1,682 a year, so a heat pump saves about £1,077 a year on standard electricity and about £1,252 on a heat pump tariff. A flat on direct electric heating is one of the strongest cases for a heat pump there is, and that is worth putting in writing to a freeholder. See our storage heaters versus heat pump comparison if your flat has night storage heaters, which run cheaper than peak-rate direct electric.

This is the biggest practical barrier. The outdoor unit needs to be mounted on an external wall, placed on a balcony, or positioned on shared ground near the building. All of these require freeholder or management company approval.

Check your lease first. Some leases explicitly prohibit external alterations. If yours does, you will need a formal lease variation (which the freeholder can grant but may charge for) or you will need to explore alternatives.

Write a formal request. Include what the unit looks like (similar to an air conditioning unit), its sound level from the manufacturer's data sheet (small units such as the Grant Aerona 290 range are 40 to 46 dB(A) at one metre), the MCS 020(a) sound calculation the installer will carry out, and the fact that the work is part-funded by a government grant. See our heat pump noise guide for the full decibel comparison to share with your freeholder.

Check the planning rules. In England, permitted development covers only one air source heat pump on or around a block of flats, and its outdoor unit can be no larger than 0.6 cubic metres, against 1.5 cubic metres for a house. It must also pass the MCS 020(a) sound calculation, which counts the other flats in the block as neighbours, and it cannot go on a pitched roof or within one metre of the edge of a flat roof (GPDO Schedule 2, Part 14, Class G; Planning Portal). If another flat in the block already has one, or your unit is larger, you will need to apply for planning permission. A block of flats must consist wholly of flats for these rights to apply, and a listed building always needs planning permission.

Suggest a communal system. For blocks of flats, a communal heat pump system serving several flats is often more practical than individual units. The freeholder installs one larger system and the cost is shared. This avoids multiple outdoor units and simplifies maintenance.

External wall mount. The unit can be mounted on brackets on an external wall, similar to an air conditioning unit. This works for ground floor and low-rise flats. The wall must be structurally sound enough to take the weight, which for small monobloc units is around 100 kg (Grant quotes 99 kg empty for its 4 kW Aerona 290).

Balcony. If you have a balcony, the unit can sit on the floor with clearance all round for airflow, as the manufacturer specifies. Check that your balcony can support the weight and that the noise will not disturb neighbours above or beside you.

Ground level. For ground floor flats, the unit can sit on a concrete pad in a garden or patio area. This is the simplest installation and keeps noise furthest from upper floor neighbours. You may need to fence or screen it for visual impact. Anti-vibration pads reduce noise transmitted through the ground.

Noise is a bigger concern in flats than houses because neighbours are closer, and under MCS 020(a) the other flats in the block count as neighbours. The calculation starts from the unit's sound power and allows for distance and reflecting surfaces. Worked through the MCS 020(a) formula, Grant's 4 kW Aerona 290 (sound power 48 dB(A)) mounted on a wall comes out at about 31 dB(A) three metres from a neighbour's window and 26 dB(A) at five metres, inside the 37 dB limit; its 6.5 kW model (52 dB(A)) comes out at about 35 and 30. On a balcony floor against a wall add about 3 dB, and in a corner about 6.

To minimise noise impact: choose a unit with a low sound power figure, use anti-vibration mounts (essential for wall-mounted units to stop vibration travelling through the building structure), and position the unit away from neighbouring bedroom windows. Your MCS-certified installer must carry out the sound calculation as part of the design (MCS). See our complete noise guide.

If your freeholder refuses or the building is unsuitable, consider these alternatives.

Air-to-air heat pump. These are smaller and can sometimes be installed with fewer objections. They provide heating and cooling but not hot water, so you still need an immersion heater or electric boiler for hot water. Since April 2026 the Boiler Upgrade Scheme pays £2,500 towards an air-to-air heat pump in a home, against £7,500 for an air-to-water one (GOV.UK), and since May 2025 they can use the same permitted development rights in England, provided they are not used only for cooling.

High-efficiency electric radiators. Modern electric radiators with smart controls can suit a well-insulated flat. No external unit, no freeholder permission needed. They are direct electric heating, so each unit of heat costs a unit of electricity, which makes them dearer to run than a heat pump and, at the standard rate, dearer than storage heaters charged on an off-peak tariff.

Infrared heating panels. Ceiling or wall-mounted panels that heat people and surfaces directly rather than the air. No installation beyond an electrical connection. They are also direct electric heating, costing around three times as much per unit of heat as a heat pump running at 2.78, so they suit small, well-insulated rooms used for short periods.

Before installing any heating system, check your flat's insulation. Top-floor flats lose heat through the roof (just like houses). Ground-floor flats lose heat through the floor. All flats can lose heat through single-glazed windows and draughty doors. Draught excluder strips give an immediate improvement.

On our model, insulation moves the running cost more than the size of the flat does. A 2 bed flat with good insulation (EPC band C) needs 5,432 kWh rather than 6,390, runs at a seasonal efficiency of 3.05, and costs £469 a year on standard electricity against £481 on gas, so it beats gas on either tariff. The same flat with poor insulation (EPC band E) needs 7,093 kWh at 2.55 and costs £732 on standard electricity against £628 on gas, and £520 on a heat pump tariff, only £108 a year less than gas. Those efficiencies are the quartiles measured in the Electrification of Heat trial; the same trial found no significant difference by the age of the home where an installer had judged it suitable, so treat the poor case as cautious. Insulating first is what makes the heat pump pay, not the other way round.

Loft insulation (top-floor flats), window upgrades, and draught-proofing are all available through ECO4 for qualifying households until it closes on 31 December 2026, and in England households on a low income can ask their council about the Warm Homes: Local Grant. Calculate your insulation savings and check your grant eligibility.

Anti-vibration pads under the outdoor unit are especially important in a block, where vibration travels through the structure to your neighbours.

Installed prices from DESNZ Boiler Upgrade Scheme statistics, August 2026 release (Table A1.3A, median cost by capacity, 2025/26; Table Q1.1A, quartiles for April to June 2026). Heat pump efficiency from the Electrification of Heat Demonstration Project performance report (Energy Systems Catapult for DESNZ, December 2024). Energy prices from the Ofgem price cap for October to December 2026. Heat pump tariff from Cosy Octopus at October 2026 rates, as costed in our tariff guide. New gas boiler cost from the DESNZ Boiler Upgrade Scheme summary business case. Grant from GOV.UK BUS. Planning rules for blocks of flats from legislation.gov.uk and the Planning Portal. Noise method from MCS 020(a), with unit sound levels from the Grant Aerona 290 data sheet. See our methodology.