DIY double glazing for your windows

Published 31 March 2016

DIY double glazing for your windows

In the cooler weather I can feel cold air coming in through the southerly facing windows.  After installing ceiling and underfloor insulation through Sustainability Trust, the heat loss through the windows became much more obvious.

Over Easter I installed window film and immediately detected a reduction in cold coming in through the glass. They say that a fully insulated house can lose up to 48% of heat through windows and double-glazing can reduce this by half.

I believe it. Window film isn’t exactly double glazing but it is noticeably effective and much more affordable.

Window film was easy to install and doesn’t detract from my view during the day and I close my curtains at night to help keep the heat in. 

Here’s what you need to install the window film:

• A window film kit and extra tape – available at the EcoShop.

• A craft knife to cut the plastic film.

• A hairdryer.

• A measuring tape (optional if you have smaller windows like mine).

• Working space to cut the plastic (again optional if you have smaller windows).

• Window cleaner and drying cloth.

The kits have the full instructions but here’re the simple steps:

1. Clean the window glass and make sure it is totally dry – you don’t want to leave any moisture on it as it will fog up the window. If your outside putty is cracked it could let moisture in and this will cause condensation as well.

2. Clean the frame so the tape can fully stick. You need to ensure the film creates an airtight cavity between the glass and the film.

3. Measure the window including about 2cms into the frame and cut the film to size or you can skip this step if your windows are small like mine.

4. Stick the supplied double-sided tape to the frame on all four sides and overlap at the corners and push firmly down then pull off the cover strip to expose the adhesive.

5. Carefully stick the film to the tape and keep it as taut as possible. Press the film firmly down on the adhesive to ensure the air can’t get behind the film at any point.

6. Use the hairdryer on the film to tighten so that all wrinkles have disappeared from the film.

7. Trim off the excess film around the edges if necessary.

If you want to see how to do it there will be demonstrations at the upcoming market on Saturday 9 April and we’ll have the kits and extra tape for sale there. If you want your home to have a comprehensive and free energy audit using the WCC or UHCC programme then you can get the window film subsidised.

Tip: Don’t run out of tape and improvise with normal double-sided tape as I’ve tried it and it doesn’t work.