No one wants a stuffy room or mould to grow in their house, so you need to leave a window open once in a while, however, leaving it open all day and especially when you heat the house means lots of heat is lost.
You’re opening the window to wasted money. Try to avoid leaving the window open in the evening when you heat the house. Instead, leave it open during the day while you’re out to freshen it up, when the heating isn't on.
Curtains can also make a big difference on how hot or cold a room is. When they are closed, curtains will act as insulation limiting the amount of heat lost to the surroundings. It’s good practice to close curtains when you’re heating the house, especially if there are radiators underneath a window.
On sunny days, leaving the curtains open will help warm up your house more and reduce the amount of heating you need. In winter, a sunny day is an opportunity to save money and use the sunlight to warm the house. During summer you can use this to keep cool by closing curtains during the day.
It’s hard to quantify how much energy saving this will make. These little actions add up to a big difference.
