The Energy Saving Trust published its response to the Scottish Government's consultation on permitted development rights (PDR) to support the provision of new homes on 27 October 20251. The response sets out the Trust's positions on how PDR for domestic air source heat pumps (ASHPs) in Scotland should change, covering installation standards, heating and cooling use, unit numbers by house type and connections to heat networks1.
On installation standards, the Trust said the PDR reference for domestic ASHPs should be revised so that compliance with Microgeneration Certification Scheme (MCS) 020 a) is explicit for an installation to count as permitted development1. On use, it agreed that ASHPs installed under PDR should be permitted for heating and cooling but not solely cooling, arguing that installations providing only cooling would not support the rollout of low carbon heating and would add energy use without improving heating efficiency1. A homeowner wanting an ASHP solely for cooling should face a planning application, the Trust said1.
On numbers, the Trust supported amending the PDR for domestic ASHPs in Scotland to allow up to two ASHPs on a detached dwellinghouse1. It went further, recommending that planning policy include a presumption in favour of allowing more than two units on detached houses where there is no demonstrable impact on neighbour amenity1. For flatted buildings, terraced and semi-detached properties, it agreed that proposals for more than one ASHP should continue to be assessed case by case, while calling for work to fill the data and methodology gaps the Scottish Government has identified1.
"Given that around 36% of homes in Scotland are flats"
The same passage records that 18.6% are terraced and 22.8% are semi-detached1. The Trust also asked for PDR wording to clarify that limits on siting and number of heat pumps apply only to systems with an external heat exchanger, noting that internal heat pumps are now available for air-to-air and air-to-water systems and do not require an external unit, typically needing just two air vents on the external facade1. It supported PDR for the installation, repair and maintenance of connections from individual buildings to heat networks1.
Why it matters for households
PDR determines whether a householder needs to apply for planning permission before fitting equipment. The Trust's positions, if adopted, would widen what can be installed without an application: a second ASHP on a detached house, internal heat pumps that have no external unit, and the pipework connecting a building to a heat network. Its stance on MCS 020 would tie permitted development to a certification standard rather than leaving the requirement implicit. Its position on cooling keeps the focus on heating: an ASHP fitted only to cool a home would still need permission. The housing mix figures it cites indicate that most Scottish homes are not detached, so the case-by-case route it accepts for flats, terraces and semi-detached houses would remain the route for the majority. The consultation response does not itself change the planning rules for home energy equipment in Scotland; it is the Trust's input to a Scottish Government process, and the wider devolved policy background is set out in energy and buildings policy in Scotland.
What happens next
The response was originally published on 27 October 2025 and the page carrying it was last updated on 18 December 20251. No date for the Scottish Government's decision on the consultation, or for any change to the PDR, has been reported1.
Sources1 cited
- Permitted development rights for new homes: response - Energy Saving Trust, energysavingtrust.org.uk