Room guide
Loft conversion air conditioning
A converted loft is often the nicest room in the house until June arrives. Then the sun on the tiles turns it into the warmest. Here’s how a system fits under a pitched roof.
Guide figure on screen in about 3 minutes. No call-back needed.
- Best system type
- Wall or ductedA single wall unit, or a slim ducted unit hidden in the eaves.
- Typical disruption
- LowLow once the room is finished, and lower still if it goes in during the build.
- Things to check
- Wall space below the slope
- A route for the pipes down to the outdoor unit
- Whether the conversion is still being built
Why lofts get so hot
Roof tiles can reach well over 50°C on a bright afternoon, and that warmth works down through the insulation into the room. Dormer windows and roof lights add direct sun. By bedtime the loft has stored the whole day’s heat, which is why so many people in Cippenham, Burnham and Maidenhead say their converted loft is unusable in a heatwave.
Pick “Loft or top floor” in the estimate and see a guide figure for it.
Where the units go
- On the knee wallThe low vertical wall under the slope often takes a compact wall unit.
- On a gable wallThe flat end wall gives the most height and the simplest pipe run out.
- In the eavesA slim ducted unit can sit in the void, with just a grille showing.
The outdoor unit usually goes on the ground or a flat roof below, with the pipes running down the outside wall in a neat cover.
Tell the estimate where the loft is and see a figure on screen.
Mid-build or afterwards
If your conversion is still being built, tell your builder you want air conditioning. Pipes and a power supply can be laid before plasterboard goes up, and a ducted unit becomes a realistic choice. In a finished loft, a wall unit on the gable is the usual answer and can typically be fitted in a day.
Mid-build or long finished, the estimate works either way. Start it now.
Loft conversion questions
Things people ask
Will a unit fit under a sloping ceiling?
Usually, yes. Many wall units are under 30cm tall, so they fit on knee walls that look too low at first glance. The surveyor measures before recommending one.
Can it heat the loft in winter too?
Yes. The same unit runs as a heat pump, which is handy in lofts that were never properly joined to the central heating.