Class G – Air source heat pumps & air conditioning on domestic premises

 

The permitted development right of Class G allows you to install, alter or replace an air source heat pump on a residential property without planning permission. This can be a house, bungalow or a block of flats. You are permitted to install it either on the property itself or within the curtilage.  You are limited to one air source heat pump on any building or within the curtilage. The pump itself is limited to 0.6 cubic metres. Jump to here for air conditioning units.

Note that these units on commercial units, will require planning permission. 

How do I apply for permission?

You do not need to request permission, Class G is your permission. However there are a few restrictions that you need to be aware of so that you do not fall foul of the conditions within the second part of Class G.

The air source heat pump must comply with the Microgeneration Certification Scheme (MCS) or equivalent.

You can’t install an air source heat pump if you already have a wind turbine, but assuming you do not have one the pump must not be within 1 metre of the curtilage of the property. It must also not be on a pitched roof or within 1 metre of the edge of a flat roof but it can be on a flat roof.

You can’t install an air source heat pump in a listed building or scheduled monument without planning permission. If you are in a conservation area or on a World Heritage Site you can’t install it on an elevation that fronts a highway. You are allowed to install it on the front wall of a property, which is not in a conservation area or on a World Heritage Site but it must be on the ground floor storey and not above. The full legislation can be seen below.

 

Air Conditioning Units

Many Air Conditioning (AC) suppliers say that planning is not required on their websites. This is just not true. In their small print, they may state that any planning issues is down to the purchaser. But who reads all the small pint?!

Class G, excludes Air Conditioning (AC) units, thanks to G.3 (a) which states that the unit may only be used for heating!

You would need to look to extensions and alterations under Class A of Part 1. This would exclude the AC units on roofs, on the principal or front elevation etc. It may also prevent it being on side walls in conservation areas for example. If the property already has a rear extension, there may not be the scope to further extend to the rear. Placing it on the side of a rear extension might fall outside Class A as well. The issue however with Class A is that one of the requirements for any ‘extension’ is that the materials must be similar to the rest of the property. Clearly an air conditioning unit protruding is not of similar materials – it might if it was partially enclosed. You can see how complicated this gets, very quickly. If they also fail to comply with that as an extension, you will need planning permission for the air conditioning unit.

Therefore if looking to install an Air Conditioning (AC) unit tread carefully and please do not assume it is permitted development – you are likely to need planning permission.

You may decide to apply for a Certificate of Proposed Use or Development to seek confirmation that your installation is permitted development.  Planning Geek can assist with that.

Planning Geek can also assist with a planning application for an Air Conditioning (AC)  unit if required. Complete our fee proposal form here.

 

Legislation

 

Class G – installation or alteration etc of air source heat pumps on domestic premises

Permitted Development

G. The installation, alteration or replacement of a microgeneration air source heat pump—

(a) on a dwellinghouse or a block of flats; or
(b) within the curtilage of a dwellinghouse or a block of flats, including on a building within that curtilage.

Development not permitted

G.1 Development is not permitted by Class G unless the air source heat pump complies with the MCS Planning Standards or equivalent standards.

G.2 Development is not permitted by Class G if—

(a) in the case of the installation of an air source heat pump, the development would result in the presence of more than 1 air source heat pump on the same building or within the curtilage of the building or block of flats;

(b) in the case of the installation of an air source heat pump, a wind turbine is installed on the same building or within the curtilage of the dwellinghouse or block of flats

(c) in the case of the installation of an air source heat pump, a stand-alone wind turbine is installed within the curtilage of the dwellinghouse or block of flats;

(d) the volume of the air source heat pump’s outdoor compressor unit (including any housing) would exceed 0.6 cubic metres;

(e) any part of the air source heat pump would be installed within 1 metre of the boundary of the curtilage of the dwellinghouse or block of flats;

(f) the air source heat pump would be installed on a pitched roof;

(g) the air source heat pump would be installed on a flat roof where it would be within 1 metre of the external edge of that roof;

(h) the air source heat pump would be installed on a site designated as a scheduled monument;

(i) the air source heat pump would be installed on a building or on land within the curtilage of the dwellinghouse or the block of flats if the dwellinghouse or the block of flats is a listed building;

(j) in the case of land within a conservation area or which is a World Heritage Site the air source heat pump—
(i) would be installed on a wall or a roof which fronts a highway; or
(ii) would be installed so that it is nearer to any highway which bounds the curtilage than the part of the dwellinghouse or block of flats which is nearest to that highway; or

(k) in the case of land, other than land within a conservation area or which is a World Heritage Site, the air source heat pump would be installed on a wall of a dwellinghouse or block of flats if—
(i) that wall fronts a highway; and
(ii) the air source heat pump would be installed on any part of that wall which is above the level of the ground floor storey.

Conditions

G.3 Development is permitted by Class G subject to the following conditions—

(a) the air source heat pump is used solely for heating purposes;
(b) the air source heat pump is, so far as practicable, sited so as to minimise its effect on the external appearance of the building;
(c) the air source heat pump is, so far as practicable, sited so as to minimise its effect on the amenity of the area; and
(d) the air source heat pump is removed as soon as reasonably practicable when no longer needed.

 

 

Air Source Heat Pumps Page Updated:  23rd September 2023