Perhaps what is important to note is that while we can put good insulation into roofs, and plug up the holes around doors, it is the window treatments that allow the most heat to get out. In a country where there are no double glazed windows, how you treat those windows is vital.
For example, venetian blinds look good as they can keep out the visual contact with outside. They thus work against allowing the sun’s rays. The same applies to vertical blinds. But they are not effective against the cold.
To contain the heat inside a building you must allow the air between the glass and the window covering to remain there and insulate. In a building that allows the air continually to go past the glass, transmitting or absorbing heat, and then redistributing that temperature differential back into the room, it is not effective. Thus, venetian and vertical blinds are ineffective. They do not contain the air but let it circulate.
Roller blinds, or Holland blinds as they are sometimes called, are a slightly better choice. They do not allow the air to move through them. The air stays between the blind and the glass.
The next best insulators are curtains or different forms. There is the open weave curtain and the curtain with a pelmet. A pelmet is the covering over the top of the window, often made from wood. It prevents the air from escaping upwards. And in the case of heavily lined curtains that reach the floor and have an interior lining, no air will penetrate between them and the glass. They also have folds that trap more air, insulating the room further.
When you move into a new home, and you want to insulate it, you should not miss these vital points of window treatment. And to add to this is also the external treatments. You can add outside awnings that protect your dwelling from the summer sun, yet roll it back in winter to allow the summer sun to enter.
And in designing your home you can also add extra wide eaves, so sun can get in during winter when it is lower, but the eaves shade your windows and outside wall when it is hotter in the summer.
If you get involved in the design of your home before construction there is much you can put in it to help energy efficiency. But after you move into an existing home, what else can you do?
There is one more item people overlook and that is their ceiling insulation. Often it is in disarray and trades people have been up there and they have knocked this or that piece of insulation aside. And if the room below is only separated from the element by a thin layer of ceiling board, a lot of heat can escape. Most people do not understand this. But it is a bit like having a bucket with a small hole in the bottom. Despite it being an otherwise good bucket, that small hole means you will always have to keep filling the bucket. The same principle applies to ceiling insulation. If you have one ceiling with badly placed insulation you will lose all that heat eventually. Like in the bucket, the heat in the room will empty. So by repositioning these insulation pieces evenly, you can achieve a better energy usage.