Be smart: Keep your windows properly sealed

Some win­dows tilted, oth­ers com­pletely open while the heat­ing is fully turned up. If you vent­il­ate your home like this, you are waste­fully heat­ing the out­doors and lit­er­ally throw­ing money out of the win­dow. Sadly, this hap­pens in many build­ings, not only the older ones, even when the win­dows are closed. The reas­on: poor seal­ing.

In view of the dra­mat­ic increase in energy prices, there is an urgent need for action in the area of win­dow seal­ing. Well-insu­lated win­dows also bene­fit the envir­on­ment since less heat­ing energy is needed and thus few­er emis­sions are released. What is more, tightly sealed win­dows are also bene­fi­cial to the res­id­ents’ health. With thermal bridges around the win­dows, i.e. points where the sur­face is colder than the rest of the build­ing shell, there is always a risk that mold will grow after a cer­tain time.

Win­dow replace­ment is often the pre­ferred recom­mend­a­tion. But the com­plete exchange of exist­ing win­dows rarely jus­ti­fies the cost and is only neces­sary in extreme cases. Often, it is suf­fi­cient to elim­in­ate the weak points around the built-in win­dows. Actu­ally, there are two main sources of drafts. One area is the joint between the glaz­ing and the frame. The oth­er is the joint between the frame and the out­er wall and/or roller shut­ter box (win­dow reveal). The lat­ter source of draft is rel­at­ively com­mon because in the past win­dows were not always expertly installed.

There are two simple and well-known tricks for detect­ing leaks: the candle test and the paper test. In the first test, a burn­ing candle shows which way the wind is blow­ing. Altern­at­ively, you clamp a piece of paper between the frame and the win­dow and then close the win­dow. If you can pull the paper out, the win­dow is not tight.

Depend­ing on the nature of the leaks, joint seal­ants made of sil­ic­one or acryl­ic can elim­in­ate the weak points between the glaz­ing and the frame. Along the seam where the frame meets the exter­i­or wall, gun-applied seal­ants, seal­ing strips and mem­branes as well as pre-com­­pressed foam tapes are the pre­ferred choice. Exper­i­enced do-it-your­­selfers can accom­plish minor seal­ing work them­selves. How­ever, when it comes to seal­ing the cav­it­ies between brick­work and win­dow frame, a pro­fes­sion­al crafts­man should be called in. It is advis­able to hire a spe­cial­ist com­pany that is cer­ti­fied to carry out “Win­dow install­a­tion accord­ing to RAL guidelines”. Res­id­ents can then be cer­tain that the seal­ing job will not be botched.