Air to Air Heat Pump for a Rental Flat: Worth It?

The short answer for a one-bed flat

Fit one only if the old heating is failing, the lease allows an outdoor unit and the grant brings the net cost down to a figure you can justify without counting on bill savings. At the October to December 2026 price cap, electricity costs 26.32p a kWh and gas 7.97p, so a small flat saves little. The full product explainer sits on air to air heat pumps for rental properties, which this post does not repeat.

What an air to air heat pump does and does not do

An air to air unit moves heat from outdoor air into the room as warm air. There are no radiators and no wet heating circuit involved. That makes it simpler to fit in a small flat than a full air to water system, but it also means the tenant’s hot water needs a separate answer. Ask every firm exactly how hot water will be provided before you compare prices.

On funding, the Boiler Upgrade Scheme offers £2,500 for an air to air heat pump, against £7,500 for air to water. GOV.UK says the applicant must own the property, including one rented out to tenants, and the heat pump must replace a fossil fuel heating system such as gas, oil, LPG or electric. The installer applies on your behalf and must be MCS certified. One grant is available per property. Details are on the Boiler Upgrade Scheme for landlords page.

Worked example (modelled, not a real project)

This is an illustration, not a quote and not a record of any installation. Every input is shown so you can swap in your own.

Input	Value	Source
Heat needed a year	3,000kWh	Assumption: a quarter of the 12,000kWh three-bed semi in the site model
Gas boiler efficiency	90%	Site model assumption
Gas price	7.97p a kWh	Ofgem price cap, 1 October to 31 December 2026
Electricity price	26.32p a kWh	Ofgem price cap, same period
Seasonal efficiency (SCOP)	3.0 and 3.5	Site model assumptions
Installed cost	£4,000	Assumption only, not a sourced price
Grant	£2,500	Boiler Upgrade Scheme, air to air

Standing charges are left out because the flat probably keeps both supplies.

Route	Energy used	Yearly cost
Gas boiler	3,000 ÷ 0.9 = 3,333kWh gas	3,333 × 7.97p = £265.67
Heat pump, SCOP 3.0	3,000 ÷ 3.0 = 1,000kWh	1,000 × 26.32p = £263.20
Heat pump, SCOP 3.5	3,000 ÷ 3.5 = 857kWh	857 × 26.32p = £225.60

The yearly saving is £2.47 at SCOP 3.0 and £40.07 at SCOP 3.5. The net cost after grant is £4,000 minus £2,500, which is £1,500. At £40.07 a year that is about 37 years to recover from savings alone, and at £2.47 it never does. The honest reading: the grant makes the project affordable, but the running cost does not pay for it.

A flat with electric heaters is a different case

The example above replaces gas. If the flat is heated by direct electric panels or heaters, the maths changes sharply, because every kWh of heat costs the full 26.32p. Using the same 3,000kWh of heat:

Route	Yearly cost
Direct electric heating	3,000 × 26.32p = £789.60
Heat pump, SCOP 3.0	£263.20
Heat pump, SCOP 3.5	£225.60

That is a saving of roughly £526 to £564 a year, which is where an air to air unit makes most sense for a rented flat. Electric heating is on the list of systems the grant can replace, though the heat pump must still replace what is there, not sit beside it. The tenant usually pays the electricity bill, so the benefit lands with them, while the landlord carries the capital cost and the lease and consent work.

When this is not the right answer

• The boiler is sound and the flat already meets today’s minimum of EPC E. Leave it and look at insulation or draught-proofing first.
• The lease or freeholder blocks an outdoor unit, or there is no wall or balcony position that meets the noise limit. See heat pump noise and planning rules for landlords.
• The flat already has heating that counts as low carbon. The grant cannot replace existing low-carbon heating.
• You are relying on an EPC uplift. Planned EPC C rules have not been laid as regulations, so no one can say yet how an air to air system will be scored. See do heat pumps improve EPC rating.

What to check before you ask for quotes

• Lease terms on external alterations, and written freeholder consent.
• Who supplies hot water once the old boiler goes.
• The EPC and any recommendations already listed for the flat. Read heat pumps for flats for the wider picture.
• That each firm appears on the MCS register, which you check yourself on the installer checking page.
• Whether the tenant’s bills rise. Landlords who raise a rent because of upgrades should read renters rights act and energy upgrades first.
• A written quote that states the grant amount, the unit’s capacity and the noise level at the neighbour’s boundary.

Next step

Try your own numbers in the heat pump landlord calculator, or send an enquiry on the quote page. Relevant independent firms contact you; no charge to you, no obligation.