At a glance: a conservatory extension in Gerrards Cross, Buckinghamshire. We fitted 3M All Seasons 35 inside the glass roof and 3M Prestige Exterior on the outside of the side glass.
The challenge
A glass roof takes the summer sun from almost directly overhead. On a clear June day about 11 kW of sunshine can fall on a 14 m² conservatory roof, and around 7.6 kW of it comes through untreated double glazing as heat: roughly four 2 kW fan heaters running at once. The owners wanted a room they could enjoy all day, not one they had to leave when the sun came out.
What we fitted, and why
Roof: 3M All Seasons 35, fitted inside. We fit conservatory roof film on the inside of the glass. Many roofs have a self-cleaning or easy-clean coating on the outside that film will not stick to, and working on a glass roof risks leaks and falls. All Seasons 35 is a spectrally selective reflective film: it turns back far more of the sun’s invisible near-infrared heat than its visible light, so the room stays bright.
Side glass: 3M Prestige Exterior, fitted outside. Side windows are safe to reach, so the film goes on the outside, where it stops the heat before it reaches the glass. Modern double glazing has a low-e coating that traps heat, so an inside film on side glass does far less. 3M Prestige Exterior is metal-free and less reflective than many films, so the view out stays natural.
What 3M All Seasons 35 does
On 3M’s double-glazing reference, 3M All Seasons 35:
- Cuts solar heat gain by about 54%
- Cuts glare by about 65%
- Blocks 99% of UV, one of the main causes of fading
- Cuts winter heat loss through the glass by about 11%
On a clear June day that is the difference between about 7.6 kW of solar heat through a 14 m² roof and about 3.5 kW. See the June roof chart on our conservatory roof film page. Every figure we quote is the improvement you can expect over the glass you have now.
What the owners said
“Everything from start to finish was so smooth and professional. We are now really looking forward to spending our days in our conservatory extension and can already feel the difference made by the products WindowTreat installed.”
Conservatory owners, Gerrards Cross
Your next step
See the conservatory roof film we fit, and the side window film. We quote from your photos.
Conservatory roof film cost: typical prices and what changes them.
Does conservatory window film work? Our verdicts on the films we fit and the ones we avoid.
