20072011

Window insulating trick

For the longest time I've been trying to find a good way to improve the overall insulation qualities of the windows on the South side of our house - but without doing something that was either too expensive or 'tacky'. I wanted something that worked at the right price and looked alright.

So a few weeks back I decided to pay Spotlight a visit - the plan being to buy what is called header tape (basically the top bit of curtain that the hooks hang into) then buy the additional fabric to make a properly lined liner for the curtains. The theory is that by doing this you make it that much harder for the heat to transfer through the window.

Whilst looking for the inside 'bulk' that was to make up the liner I found an interesting product called 'Insul-Bright' - basically this a woolen like sheet with a foil layer in the middle. The sort of thing one would use to line oven gloves. But looking at I realized this could be ideal to use as the window lining in its own right. Its color is a perfect white, it seems to have a reasonable strength in of itself, and due to the foil it has a tendency to want to lay dead flat...

So one windows worth of Insul-Bright was bought with header tape; this was then hand sown together to form two liners to hang between the curtain and the window. The result..  What a difference - basically I normally had a two bar heater running in my office to keep things warm and to stop my fingers becoming none functional - I noticed with the liner up that the number of times the heater clicked on was reduced by about half - its was paying for itself already!

I think two things are happening here:

1. Due to the tendency of the liner to want to sit 'flat' - it forms a good seal against the window frame, turning the air between it and the window into a trapped layer of insulating air in its own right. I found this out by putting my hand in the gap and feeling the temperature difference. Also there was zero bottom draft at the bottom of the curtain - proving the cycle of heat exchange against the glass was broken.
2. I think the foil lining was doing a very good job of maintaining the heat difference across it - far better than just the curtain alone.

So, how much for this, well the Insul-Bright goes for about $13 per linear meter by roughly a meter wide. The header tape is a few cents per meter..



Obviously once this success was observed on a cold night - the same was done with the other 3 cold rooms; except this time using a sowing machine to do the hard work.