Heat pump planning rules in Wales from June 2026

What changed

The June 2026 update

The Welsh Government updated permitted development for air source heat pumps on 1 June 2026, through an amendment order. Its guidance says the new rules should be read alongside the 2012 Welsh order that first set them. The main changes are a second unit allowed on detached houses, a larger size limit of 1.5 cubic metres, a requirement to meet MCS 020(a), and the removal of the old condition about distance from the property boundary, with sound impact on neighbours handled through the MCS standard instead.

Ground and water source heat pumps were already permitted development within the curtilage of a house, and remain so.

If you're unsure whether a planned position meets every condition, the Welsh Government suggests contacting your local planning authority.

North Wales homes

Where the rules bite

Three of the conditions come up often in North Wales. Listed buildings are excluded entirely, which matters in historic town centres. Conservation areas restrict units on walls and roofs facing a road, common in terraced streets. And units on pitched roofs aren't allowed, so homes without space at ground level, such as some terraces and flats, need careful thought.

For off-gas homes on Anglesey and in Gwynedd, where oil heating is most common, detached and rural properties usually have the most space, and the two-unit allowance for detached houses can help larger homes.