Air conditioning in Richmond upon Thames

Richmond Council lists 85 conservation areas, one of the highest numbers in London. They include Richmond Hill, Kew Green, Barnes Green, Twickenham Riverside and Strawberry Hill. In those areas a heat pump outdoor unit cannot go on a wall or roof fronting a highway, or closer to the road than the house, under the permitted development rules. Listed buildings, which are plentiful around Richmond Green and the riverside, always need consent. Outside conservation areas, a unit can go on a street facing wall only at ground floor level.

Since the rules changed in May 2025, a detached house can have two heat pumps under permitted development, and the outdoor unit can be up to 1.5 cubic metres. That opens up proper whole house designs for detached homes in Twickenham, Teddington and East Sheen: for example one outdoor unit for the bedrooms and another for the living spaces. On semi detached and terraced houses the limit is one unit, so a multi split is the usual approach. The unit must also be used for heating, not only cooling, and pass the 37 dB(A) noise calculation at the neighbour's window.

Many Richmond homeowners want to cut gas use as well as stay cool. A reversible air to air system can heat the main rooms in spring and autumn and cool them in summer, while the boiler covers hot water and the coldest days. A full switch from gas is possible with good insulation, but air to air systems usually do not heat water, so a cylinder or other source is needed. The Boiler Upgrade Scheme now lists a £2,500 grant for eligible air to air installs, though MCS certified installers for these systems were not yet available as of October 2026.

The riverside from Kew to Teddington has Georgian houses, converted villas and modern flats, and many are listed or in conservation areas. For a listed house, permitted development does not apply, so both listed building consent and planning permission are needed, with a heritage statement explaining the unit position and pipe routes. Riverside flats need freeholder consent and usually planning. In both cases, a hidden rear or roof position and a clear noise assessment give the best chance of approval.