How to keep a conservatory cool in summer

Why conservatories get so hot

A conservatory is mostly glass, and the roof faces the sky. Sunlight passes through the glass and warms the floor, furniture and walls, which then give off heat that can't easily get back out. A south or west facing conservatory in full sun can become uncomfortable within an hour or two, and stays that way well into the evening.

Ways to keep a conservatory cool

Ventilation

Open roof vents, windows and doors on opposite sides so warm air can escape and cooler air can come in. Roof vents matter most because hot air rises. It helps, but it only moves heat out after it's already in the room, and it's no use when the conservatory needs to be locked.

Blinds

Internal roof blinds cut glare and some heat, but much of the heat is already inside the glass by the time it reaches the blind. They also hide the sky, gather dust and can be awkward to clean. External shading such as awnings or shade sails works better for heat because it stops the sun before it reaches the glass, but it changes how the conservatory looks.

Conservatory roof film

Solar control film on the roof glass rejects a large share of the sun's heat at the glass itself and cuts the glare that bounces around the room. Clear films keep the light and the view of the sky. Film is usually the least disruptive option because it goes on the glass you already have. It needs matching to the glass, and polycarbonate roofs need different treatment.

Fans and air conditioning

Fans make a room feel cooler but don't lower the temperature much. Portable air conditioning can, but it costs money to run and is fighting heat that keeps coming in through the glass.

A solid or tiled replacement roof

Replacing a glass roof with a solid insulated one is the most thorough fix for heat, but it's a building project, it may need building regulations approval, and the conservatory loses much of its light.

Which should you choose?

If the conservatory is too hot rather than just bright, start with the roof. For most people that means roof film, with good ventilation alongside it. If the walls also face the sun, a lighter film may be enough there. If the conservatory is also cold in winter, the right choice of film can help with both. See our guide on keeping a conservatory warm in winter.