In its latest push for landlords and other property owners to improve their Energy Performance Certificate ratings, the government has relaxed rules on heat pumps.

From May 29 – that’s just over two weeks from now – the government is scrapping the rule that no air source heat pump can be fitted within one metre of the boundary of a property under permitted development and is increasing the maximum size of air source heat pump allowable under permitted development from 0.6 m3 to 1.5 m3. 

It is also doubling the number of air source heat pumps permitted, from one to two for detached houses, to allow cascade systems to benefit from the same rules as individual units.

And it is allowing air-to-air heat pumps that can also provide a cooling function to benefit from the same permitted development rights as air to water heat pumps.

Currently most of these changes would require planning consent but that will no longer be necessary from late this morning.

Figures obtained by Swedish eco-technology firm Aira show the average waiting time for planning permission for such changes is currently two months, although that average masks many variations. 

Residents in boroughs such as Westminster, Walsall and Birmingham have to delay heat pump installation for up to six months while council planning officials work through their applications. 

The government has set a target of installing 600,000 heat pumps annually by 2028.  In 2024, around 100,000 installations were completed.