Information Leaflet # 12
Renewable Energy Development within the Curtilage for a Dwelling House-Permitted Development Rights
August 2006

Heat pump development

9. Heat pump development will typically include the installation of a heat pump, a heat collector and a heat distribution system. Heat can be collected from the ground, water or air. Ground collectors consist of loops of pipe containing a fluid which are buried in shallow/ deep trenches or deeper boreholes depending on the space available. Water collectors pump water to the heat pump and back to the source through buried pipes. Air collectors, [usually external to the building], are placed above ground level and force air through an extraction system which collects heat from the air and passes it to the heat pump. The heat distribution system is usually inside the building.

Where works are accommodated within an existing building/s or do not materially affect the external appearance of a building, a planning application will not be required. Where they involve the provision of an additional building/s (heat pump ancillary housing) to house the equipment and/or the installation of an air collector or materially affect the external appearance of an existing building, they will require planning permission. However, this may be provided by permitted development rights provided it does not qualify as an exception as set out below.

9.1 An Air Collector fitted to the roof of a dwellinghouse (Class B of Part 1 applies)

A planning application will not be required provided that:

• i. the design and external finishes are in conformity with those of the original dwellinghouse;
• ii. the fitted collector does not cause any part of the dwellinghouse to exceed the highest part of the existing roof; (see paragraphs 7.4 and 7.5 above )
• iii. the fitted collector does not cause any part of the dwellinghouse to project beyond the plane of any existing roof slope fronting a road by more than 15 cms.
• iv. the dwellinghouse is not in a conservation area
• v. when fitted, the collector does not increase the cubic content of the dwellinghouse by more than 20 cubic metres, in the case of a terrace house, or 25 cubic metres in any other case; or the cubic content of the resulting building does not exceed the cubic content of the original dwellinghouse –
• (a) in the case of a terrace house by more than 50 cubic metres or 10% whichever is the greater;
  (b) in any other case by more than 70 cubic metres or 15% whichever is the greater; or
  (c) in any case by more than 115 cubic metres;

Where the solar collectors are on a flat roof the proviso at 9.1 iii applies. See also general commentary on height and flat roofs at 7.4.

9.2The provision of heat pump ancillary housing as an enlargement, improvement or other alteration of a dwellinghouse (Class A of Part 1 applies).

A planning application will not be required provided that:

• i. the design and external finishes are in conformity with those of the original dwellinghouse;
• ii. the cubic content of the resulting building does not exceed the cubic content of the original dwellinghouse –
• (a) in the case of a terrace house or in the case of a dwellinghouse in a conservation area, by more than 50 cubic metres or 10% whichever is the greater;
  (b) in any other case by more than 70 cubic metres or 15% whichever is the greater; or
  (c) in any case by more than 115 cubic metres;
• iii. the enlargement, improvement or alteration do not cause the part of the building enlarged, improved or altered to exceed the height of the highest part of the existing roof;
• iv. the enlargement, improvement or alteration do not cause any part of the resulting building to be nearer to any road which bounds its curtilage than the part of the original dwellinghouse nearest to that road;
• v. the enlargement, improvement or alteration do not cause the part of the building enlarged, improved or altered to exceed 4 metres in height where it is within 3 metres of the boundary of the curtilage;
• vi. the total area of ground covered by buildings within the curtilage (other than the original dwellinghouse) does not exceed 50% of the total area of the curtilage (excluding the ground area of the original dwellinghouse);
• vii. the building erected is not within the curtilage of a listed building.

A planning application will not be required provided that:

• i. the building altered or provided does not become nearer to any road which bounds the curtilage of the dwellinghouse than the part of the original dwellinghouse nearest to that road;
• ii. the building altered or provided does not have a cubic content greater than 10 cubic metres where any part of it is within 5 metres of any part of
  the dwellinghouse;
• iii. the height of the building altered or provided does not exceed 4 metres in the case of a building with a ridged roof or 3 metres in any other case. (see paragraphs 7.4 and 7.5);
• iv. the total ground area covered by the buildings altered or provided (other than the original dwellinghouse) does not exceed 50% of the total area of the curtilage (excluding the ground area of the original dwellinghouse);
• v. the building altered or provided does not have a cubic content greater than 10 cubic metres where it is on land within a conservation area, an area of outstanding natural beauty, a National Park, or within the curtilage of a listed building.