Deflecting the Ultra Violet

August 21st 2022, Our House, Derby

The combination of the recent record breaking heatwave and the south facing windows in our kitchen have made it, a place often full of hot and boiling things, a pretty warm and humid place.

The kitchen door and windows

This is not a new thing to us. We have lived here for a long time now. Controlling the heat in our also south facing conservatory is something we’ve gotten quite good at. Opening windows and running the big ceiling fan helps a lot but by far the most effective measure we put in place was fitting a protective UV film on the roof.

Install kit and window film

Measuring and cutting

To combat the heat in the kitchen I purchased some clear, museum quality, window film from Active Window Films.  It blocks 99.5% of all UV rays from entering the room keeping heat out and stopping things fading.  It’s the same stuff used in the Louvre in Paris to protect the exhibits so it should be good enough for us.

Rolling the film

Unlike the conservatory I’d be fitting this.  Having rolled out the film I carefully measured the windows and marked them out on the film making sure to leave the recommended extra 3ish cm on each side.

Cutting ready to install

Marking done I cut out the three individual pieces so they were ready to be installed once I’d prepped the windows.

Prepping the windows

Prepping and Squeegeeing

Window prepping was easy. I made myself a slip solution to the recommended mix of washing up liquid and water and cleaned the windows as instructed.

By far the hardest part of the process was removing the clear protective film from the actual clear window film.  I needed to do this to get at the adhesive.  It wasn’t easy and impossible to photograph.  I did eventually manage to get them apart and once it was off I sprayed both it and the window using the same slip solution I’d used to prep the windows.

Fitting the film

Fitting the film to the windows was also pretty easy. The slip solution lived up to its name allowing me to move the film into a position I was happy with.

Film on the kitchen door

Now I had to be quick. Working first left to right then top to bottom I used the squeegee that came in the, overpriced for what it was, Install Kit to force the air bubbles out from behind the film. This was very satisfying to do.

Ready for trimming

Film squeegeed the only left to do was trim away any excess film using the knife, also in the Install Kit, before forcing those freshly neatened edges behimd the rubber windows seal.

The Big Reveal

It’s at this point there would be somekind of photo of the final result.  A picture of the windows showing the film in place, except there’s no point.  Just like it says it’s a clear film, you can’t see that it’s there are all.  The windows look exactly like they did before.  So I turned my attention to trying to prove if the film does actually work instead.

Top window with film
Bottom window without film

Using my new Thermal Imaging Camera I did take some before and after photos.  They give a direct comparison of the temperature of the top window with the film fitted to that of the bottom window that didn’t.  It showed the top window was almost 3°C hotter on a day that wasn’t actually that warm. Like in the conservatory the film reflects heat out and will therefore keep the kitchen cooler.

Door before
Door after

I got a similar result on the larger back door window. Admittedly not taken at exactly the same time it shows once the film was fitted that window was 5°C hotter than without it.

Day to day it’s actually quite hard to say how effective the film will be. Though it’s been warm it’s not been hot like it was in July and its only going to getter cooler as we had into Autumn.  Time will tell but I’m confident it will help going forward, so confident in fact I’ve already fitted the same film on the south facing windows in our utility room.