Householders in Wales will find it easier to install air source heat pumps after changes to planning rules removed some of the main barriers blamed for slowing take-up of low-carbon heating.

The new permitted development rights, which came into force on 1 June 2026, mean many installations can go ahead without a full planning application, provided they meet noise and siting conditions.

One of the most significant changes is the removal of the previous requirement for an air source heat pump to be at least three metres from the boundary of a property. The size limit for outdoor compressor units at homes has also increased from one cubic metre to 1.5 cubic metres.

Detached houses can now have up to two heat pumps under permitted development rights, rather than one, as long as the combined operation of the units meets the required sound standard. Installations must comply with MCS 020, the industry method used to calculate noise from air source heat pumps, with a 40dB limit applying in relevant cases.

The changes also allow heat pumps to be installed on a wall or roof facing a highway in more circumstances. Air-to-air heat pumps are being brought within the scope of permitted development, widening the types of systems that may be fitted without a separate planning process.

However, the rules do not amount to a free-for-all. Heat pumps still cannot be installed on a pitched roof. Where a unit is placed on a flat roof, it must not be within one metre of the external edge. Planning permission may still be needed for listed buildings, homes in conservation areas, or properties where permitted development rights have been removed by the local planning authority.

The Welsh Government has said the move is intended to support cleaner heating and reduce unnecessary delays for homeowners. Industry bodies say the relaxation should make installations easier in terraced streets and other properties where the old three-metre rule left few practical options.

Campaigners for clean heat have welcomed the direction of travel, arguing that planning rules can add cost and uncertainty to households considering a switch from gas or oil. But they have also warned that clear guidance will be needed so residents, installers and councils understand when a planning application is still required.

Heat pumps are expected to play a growing role in cutting emissions from homes, but installation rates remain below the level needed to meet long-term climate targets. Supporters of the rule change say simpler planning is only one part of the challenge, alongside upfront costs, consumer confidence and the availability of trained installers.

Homeowners are being advised to check with their local council before starting work if their property is listed, in a conservation area, or subject to special planning restrictions.