In one of our earlier articles, we touched on how the position of windows in your house can affect your home heating. In short, south-facing windows take advantage of the heat of the sun, while north-facing windows do not. If you are in the process of having a new house designed, the best approach is to keep your north-facing windows to a minimum, and put relatively large windows facing towards the south. This will lower heat losses through the northern side of the house, and allows the sun’s heat into the building from the south.
A bonus to this is that large windows on the southern side will increase daylight levels in the house, which helps reduce the need for electricity and artificial light, so providing a more natural, well-lit living environment. Bear in mind though that big windows will also lose more heat than small windows, so a balance needs to be found between heat losses and solar gain through your windows. Fortunately, modern high-quality windows are good at maximising gain while at the same time reducing heat loss, so it’s wise to pick the best windows that you can afford.
These days, “modern high quality windows” generally means well-made triple-glazed windows, and as they are becoming more common, their price has come down and they are now much better value for money than in the past. They are also much more easily obtained than before, so they are now a very real option for a new or even an existing house. Keep in mind that there isn’t much point in super-insulating the rest of your house if you are going to lose your heat through poor quality windows and doors.
Triple glazed windows have a number of advantages over double or single glazed windows:
• You won’t feel a drop in temperature when you stand next to a good-quality triple glazed window, as you would with a double or single-glazed window.
• Draughts are reduced in triple glazed windows because they have two seals around the edges (the others only have one). One seal is to keep the weather out, and the other is to improve airtightness.
• Sound insulation is better.
• Three panes of glass separated by low-conductivity spacers at the edges does away with the risk of condensation at the edge of the glass, as you would have with double-glazing. We have all seen condensation around the edge of the glass, and as well as being unsightly it can lead to the rotting of timber window frames over time.
• Triple glazing will still allow the sun’s heat to pass through from the outside, albeit at a slightly reduced level compared to double glazing. However, much less heat will be lost through a triple glazed window than through a double-glazed window.
• Triple glazing has a layer of insulating gas between each glass pane. These two layers help reduce heat escaping out through the glass and give an obvious advantage over double glazing, which has only one gas layer.
• The window frame will usually be well-insulated, and have a “thermal break” to prevent heat loss through the frame.
• A triple glazed frame will have a much stronger construction than a double glazed window, because of the additional weight of glazing involved.
• Traditionally, radiators are positioned beneath windows in order to heat the cold air coming in through double or single glazed windows. With the advent of well-made triple glazed windows this isn’t necessary any more. It allows a little more flexibility with your room layout.
We haven’t yet mentioned external doors. These are some way behind the advances in windows in that a highly insulated solid door, say to Passive House level, is very expensive and perhaps not great value for money just now. The way around that is to have your outside doors constructed as if they were triple glazed windows, in other words they would be fully glazed rather than solid. If you wanted to, you could then install a more traditional type front door on your draught lobby inside the front door to give a more solid feel to the entrance to the house.
Now we have covered all the elements that relate to keeping your heat in the house. The final part of the jigsaw is to decide which heating system to use, and we’ll look at that in our next article.
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