Why does my conservatory become too hot to sit in, and can it be fixed?
Conservatories are almost always built outside the thermal envelope of the house, which is why they can be twenty degrees warmer than the rooms next to them. The fix depends on how much you are willing to change. Roof treatment, internal shading and improved ventilation will rescue most conservatories. Without those, even powerful air conditioning is fighting a losing battle.
What it usually looks like
These are the symptoms readers describe most often. None of them alone is diagnostic, but together they build a picture.
- Room above 35°C on sunny days
- Unbearable within an hour of sunrise
- Adjoining room overheats whenever the door is open
- Plants wilt despite watering
Most common in: Conservatory
Before you buy anything
Watch the house respond as you scroll.
These checks are listed in the order we would work through them. The illustration on the left changes with each one, so you can see what each check is actually addressing before deciding whether it is worth doing.
A glass roof and glass walls. There is no version of this room that is comfortable in August without intervention.
Look at the roof material
Polycarbonate and old glass roofs admit huge amounts of solar gain. A solid roof retrofit or reflective film transforms the room more than anything else.
Assess the orientation
A south or west facing conservatory will need much more aggressive intervention than a north facing one. Knowing this shapes every other decision.
Plan for cross ventilation
A single opening window leaves hot air with nowhere to go. Roof vents, side windows or a powered extract make a substantial difference.
Add external or in-roof blinds before internal blinds
External shading stops the heat before it enters. Internal blinds only catch it once it is already inside.
Decide whether the conservatory should be a year-round room
A genuinely habitable conservatory needs to be brought inside the thermal envelope, which is a building project. If the room is occasional, lighter measures may be enough.
Products that may help
Only consider these once the checks above have been ruled out. A product fitted into the wrong cause is rarely satisfying.
The cheapest answer to conservatory unusable in summer is usually the one that addresses the cause rather than the symptom. The list above is in the order we would work through it, because the checks at the top tend to rule out the most expensive mistakes further down.
Run the Home Comfort Score for this room
A two-minute reading gives you a number to compare against after each improvement, so you know what is actually working.