From The Observer
If you are considering double glazing, you must already have insulated your roof and walls. In an ‘ordinary’ home you lose 25 per cent of heat through the roof and 35 per cent through the walls, so they must be your priorities, unless your house is made of windows.
New buildings now have to meet new standards of insulation and are often fitted with double glazing when built. Usually this factory-made double glazing does not just add to the comfort, but is very well designed and actually looks quite good. Still, it’s a difficult decision to double glaze an existing home, since you’re going to have to spend a lot of money on what will save you about 10 per cent of the heating bill in an ordinary small house.
Of course, there are other benefits besides the financial one. The room will be much more comfortable. You won’t get a chilly feeling when sitting near the window and draughts will be fewer. So, on the whole, if you have money, double glazing is not a foolish investment, though even good double glazing won’t be as effective as a brick wall!
Double glazing is not just ‘Double Glazing’. There are several ways of achieving it. You can install ‘replacement windows’ with two sheets of single glass. Or you can have ‘secondary windows’, either fixed to the existing window or sealed to it. Secondary windows are cheaper, can often be installed by the owner, but are not likely to be so efficient as replacement windows.
If you want to do the job yourself, the simplest form of double glazing is the applied frame method, which means fixing a second pane of glass directly onto the original frame using beading or special frame sections. The most important thing is that any opening in the second leaf should be completely blocked with a long-lasting material.
Points to check are that condensation will not occur between the two panes; that you will be able to open ‘openable’ windows, (or that you’re prepared to give up that luxury); that you will be able to clean the window and that you have some other way of letting fresh air in. If you think that by double glazing you automatically insulate against sound too – think again. To have a noise insulating effect, the two leaves will need a gap of 110 mm or 200 mm; so double glazing with noise insulation needs to be specially made.
It is more difficult to make it look nice and to fit it into the existing window openings. Moreover, with this gap it won’t work as well for heat insulation. So, if you don’t live directly under Concorde’s flight path, it will hardly be worth insulating for sound.
A. Which paragraph focuses on each of these ideas as the main idea? Write the number of the paragraph in the blank.
1. Double glazing is expensive. 2. You can do your own double glazing if you are careful enough.
3. There are mainly two ways of double glazing. 4. In a house, mainly the roof and the walls should be insulated. 5. Double glazing is useful.
6. A special kind of double glazing is required for noise insulation.
B. What do the following refer to?
1. ‘one’ (line 13): 2. ‘it’ (line 22):
3. that luxury'(lines 32-33):