Air Conditioning for Conservatories

Why conservatories are a special case

A conservatory has far more glazing per square metre of floor than any other room, so solar gain is enormous. On a sunny day a south-facing conservatory can climb 15°C above outdoor temperature within a couple of hours.

That means standard sizing rules based on floor area alone will substantially undersize the system. A properly calculated heat load accounts for glazing area, orientation, glass specification and roof type.

Typical capacity requirements

• Small conservatory (up to 10m²): often 3.5kW rather than the 2.0kW a normal room that size would need.
• Medium conservatory (10–16m²): typically 5.0kW.
• Large conservatory (16–25m²): typically 7.0kW, or two indoor units on a multi-split.
• Polycarbonate roofs increase the requirement significantly compared with insulated or glass roofs.

Reduce the load before you size the system

Every measure that reduces solar gain lets you fit a smaller, cheaper unit that runs less often — so it's worth doing this thinking before getting quotes.

• Solar-control film or self-cleaning solar glass on the roof cuts gain dramatically.
• Roof blinds or a replacement insulated roof panel reduce the peak load.
• External shading or planting on the sunniest elevation helps more than internal blinds.
• Trickle ventilation and openable roof vents help remove hot air.

Winter use matters too

Conservatories are often as unusable in January as they are in July. A heat-pump system solves both problems with the same equipment, which is a big part of why conservatory installations are so common.

Where a conservatory has no radiator (common, because of building regulations around thermal separation), a reverse-cycle unit is frequently the most practical heating option available.