Windows are panes (owwwww, the pundamonium) when it comes to trying to make your house energy efficient. They are the weakest 'thermal' link in your house and account for a huge amount of heat loss and heat gain.
If you live in a cold climate, you know you have to insulate your windows to keep your house warm in winter.
Double (or triple) glazing works well but is often expensive to retrofit but there are some really simple ways of trapping a layer of still air using plastic window insulation film.
If you live in Europe, Canada or North America you can buy this stuff, put it over all your windows for winter and take it down in Summer. It's a cheap, disposable product.
It's called window insulation film and is a bit like shrink-wrap plastic. You stick it around the frames of your windows with a double sided tape, blast it with a hairdryer until it is tight like a drum and then let it work it's insulating magic.
In Australia we have, until recently, had only one supplier of the window film (Clear Comfort) but now we have a bit of healthy, energy efficient competition in the market. You could perhaps also buy it cheaper from online stores but where possible, great to support an Aussie business.
Installing the window film is a great GIY job (here's my GIY video's on how to do it) and an overnight success, literally.
Our house was getting terrible condensation on the windows - it was like it had rained inside each evening. This happens when warm moist air from the room (and my gas bagging) hits the cold glass. It condenses (goes from being a water vapour in the air to water on the window) and drips down onto the window frame causing mould and rot. Nice!
After installing the film on some of the windows the difference was incredible (the pic above has window film on the left pane and none on the right pane).The windows that have the window insulation film have no condensation on them and those with the old single pane of glass are dripping with condensation.
Love science that science in action. It works because the temperature of the inside pane of glass (or plastic in this case) is warmer than the outside pane because it is insulated by the layer of still air. The water vapour in the air doesn't condense on warm surfaces.