Aspects of Double Glazing

When choosing double glazing window designs for your home, there are a number of design aspects that are rarely discussed at the buying stage, but are worth bearing in mind to ensure the finished installation matches your expectations.

An important issue is line of sight. When manufacturing double glazing windows, it is normal for there to be smaller areas of glass wherever there are openings (sashes) fitted. Where the frames are fixed, the glass area will be larger. This 'unequal' sight line is quite normal and acceptable to most people.

On many older properties, however, it was more common to have an equal light line. In effect, you would not be able to tell from the outside which windows opened and which did not. Fitting 'dummy sashes' or 'dummy openers' into the frames created this 'equal' sight line. As shown here, the windows can have a considerably different appearance depending on whether or not the sight lines are equal.

Although not everyone appreciates the bulkier appearance that comes with equal sight lines, there are some properties for which this approach is preferable. It is also a very good alternative with Georgian and Leaded Light window designs as it allows you to have rectangles or squares that are more equal in size.

Another possible alternative is to consider having vertical equal sight lines in which fixed windows are always above fixed windows and opening windows above opening windows.

Ultimately, having equal sight lines will add to the overall cost of your replacement windows and many buyers do not feel the extra cost is worthwhile.

Another design issue that is often overlooked is whether to use black or white gaskets on your white double glazing. Black gaskets are the standard choice of most double glazing companies. In the past, white gaskets had not been favoured as it was not always possible to match the white of the UPVC frames. Nor was it possible to offer a 'colour fast' guarantee. Today, technology has moved on and more companies now offer both alternatives with confidence. In our view, white gaskets are a good choice, particularly on white UPVC 'panelled' doors.

An alternative to white gaskets are 'low profile' black gaskets which are very slim and less obtrusive.

Finally, think about your neighbours when replacing windows. It is sometimes worth considering the effect of your new windows on the overall appearance of the street or area where you live.

For instance, if you and your next-door neighbour both agree on a style for your windows the overall effect can be considerably enhanced if you both agree to use similar designs. It doesn't matter if you both use the same company or even have the work done at the same time. As can be seen here, using almost identical designs on both of these porches has added to the visual appearance of these two neighbouring houses.

Special note: We will be looking at other design aspects of replacement windows from time to time. If you have a tip to share or a point you feel we should make, please e-mail us by clicking here.