Did you know that glass can be the cause of around 10-20% heat loss in winter and around 25-35% heat gain in summer.
Windows are not a very good insulator at all and are a bit of a mixed blessing. You can let a cool breeze flow through at the end of a hot day and it can let out VOC pollutants and cleanse the internal air.
DIY Double Glazing
Also with the aid of curtains, we also cover the insides of our windows on hot days and cold nights to stop heat transfer either way. However, curtains must have a very important feature in which to work more effectively and that is to install a box pelmet.
This example is a Holland blind with a closed pelmet in Kim’s office, which was installed during the last retrofit. This room is on the south side of the house, but stays quite warm in winter.