Is it worth improving the glazing? Doesn't the glazing industry already do its best possible? Quick link: download the Instructions for window films (German only) .
The straightforward answer is: yes and no. It depends on the type of glazing that currently exists in the relevant window. Quite often, the glazing is old, from the days when building components were by far not as good as those available today. At this point one could argue that wouldn't it be better to replace the glazing or even better to renew the entire window? Yes, in terms of energy efficiency that is always the best solution, provided that really good components are actually chosen: those are always only the ones with
All other window designs need to be improved - and unfortunately that's still most of them. But if I had just renewed my windows 5 or even 20 years ago, then an earlier-than-planned renewal3) there are still a great many, we have conceived a “retrofit”. It is presumed that such a measure, and therefore the old window, will continue to be used for another 5 years at least.
This is what the priorities actually look like if something has to be considered:
If the glazing is already triple low-e glazing - that is the only case in which we do not recommend any of the measures described here as they will bring almost no benefit. How do I find out whether there are three glass panes? By looking for two edge bond seals at the glazing edge. You can see whether the panes also have a low-e coating by using the lighter or torch reflection method, see Instructions for window films. ( German only)
Quick link: download the instructions Instructions for window films. (German only)
First, measure the size of the film to be applied: always measure about 1 cm further than the glazing bead.
Then there is the information based on which you can purchase/order the material: it is called “insulating film/foil” 4). There are a number of different manufacturers, it is worth comparing the prices (including delivery costs).
It is better to clean the window thoroughly before applying the film (using tape), and to wait until everything has really dried (we don't want a lot of water vapour in the air layer as otherwise it will lead to condensation).
Depending on the kind of existing old glazing, this will always help a little to different degrees. It is also possible to estimate the economic efficiency. We did not take the hours of work into account initially - anyone can do that for themselves because this also depends on how much time is required and how it is assessed. But even if the net wage of a skilled worker is assumed, this will usually pay off. The material costs are already very small.
Old glazing | Benifit? | Amortisation period |
---|---|---|
Saved losses glazing | in months | |
Newer douple-paned insulated glazing | 22% | 13 |
Double-paned insulated before 2005 | 27% | 8 |
Old double glazing | 40% | 3 |
Very old single-glazing | 57% | 1 |
This “pays off” surprisingly well even if we include the hours of work. In addition, the inside of the room will become more comfortable because the inner side of the window is now less cold, and in the event that heating energy becomes scarce, one can not only save on this but also the room temperature will stay bearable even if heating is not possible in the worst case. Coming back to the beginning, everything will be even better if a really good quality new window with triple low-e glazing is installed in place of the old window. Keep that in mind when the time comes!