Planning permission is not usually required for an air source heat pump, including within the National Park, provided it meets the permitted development rules.

Planning permission may be required if:

• It does not comply with the MCS Planning Standards
• The outdoor compressor unit exceeds 1.5m³ at a dwellinghouse
• It is installed on a pitched roof, or within 1m of the edge of a flat roof
• It is within the curtilage of a listed building
• It is installed on a scheduled monument
• In a conservation area, it is installed on a wall or roof fronting a highway, or is positioned nearer to a highway than the part of the house nearest to that highway
• It does not meet any of the other limitations or conditions of permitted development

Up to two air source heat pumps may be permitted at a detached house. For other houses and blocks of flats, the limit is one.

The heat pump must not be used solely for cooling. It must, as far as practicable, be positioned to minimise its effect on the appearance of the building and the amenity of the area, and must be removed when it is no longer needed.