Guide · Updated 8 November 2026
Air to air heat pump vs air conditioning
The hardware is almost the same. A modern split air conditioner that can heat is a reversible heat pump. The difference is purpose: an air to air heat pump is chosen and sized to be your main heating and cools as a bonus, while air conditioning is chosen for cooling. That difference decides whether you can get the £2,500 grant and, in England, whether you need planning permission.
Side by side
| Air to air heat pump | Cooling-only air conditioning | |
|---|---|---|
| Heats | Yes, designed as main heating | No |
| Cools | Yes | Yes |
| Sized for | Coldest winter days | Hottest summer days |
| £2,500 grant (England and Wales) | Yes, if it replaces fossil or electric heating | No |
| Planning in England | Usually permitted development if it meets MCS 020 | Not covered by permitted development; usually needs planning permission |
| Installer | F-gas; MCS for air to air if claiming the grant | F-gas |
"Reverse cycle" air con and heat pumps
Most split air conditioners sold in the UK today are reverse cycle: a valve flips the refrigerant flow so the indoor unit blows warm air instead of cool. That makes them heat pumps. What separates a good air to air heat pump installation from an air con install is the design work: a heat loss calculation for each room, a unit with a strong heating performance at low outdoor temperatures, and a plan for the whole home's heating.
Portable air conditioners are different
Portable units with a hose out of the window are not heat pumps in this sense. They're less efficient, noisier inside, and don't qualify for grants. They're a stopgap for a heatwave, not a heating system.
Which do you need?
- You want to replace gas, oil, LPG or electric heaters and would like cooling too: an air to air heat pump, sized for heating, from an MCS certified installer.
- You only want to cool a bedroom or office and are keeping your boiler: a split air conditioner is fine, but it won't get the grant and may need planning permission in England.
Questions
Is an air to air heat pump the same as air conditioning?
The equipment is very similar, and reversible split air conditioners are heat pumps. The difference is design and purpose: an air to air heat pump is sized as your main heating, which is what the grant pays for.
Can air conditioning heat a house?
A reverse-cycle split system can, and efficiently. To heat a whole home it needs to be sized room by room for winter, which is what an air to air heat pump design does.
Do I need planning permission for air conditioning?
In England, cooling-only units aren't covered by permitted development, so usually yes. Units that heat and meet MCS 020 are usually permitted development, with limits for flats, listed buildings and conservation areas.
Sources
- TechRadar: Air conditioning isn't banned, the planning rules explained (Jul 2026)
- Planning Portal: Heat pumps
- GOV.UK: Discounts for families to keep warm in winter and cool in summer (18 Nov 2025)
- DESNZ: Air-to-air heat pumps literature review
Checked 8 November 2026.