The energy efficiency of buildings is a very current topic, so in my graduation thesis, I
decided to analyze the potencial for energy retrofit of a small multi-family building and also
how to provide more daylight in the spaces. I checked the differences between different
levels of insulation, provided by building’s thermal envelope. I used five thermal insulation
products with different thermal resistence and four windows with different glass type and
I discovered that it is almost impossible to achieve the law requirements with the annual
needed energy to heat up a building and that the amount of daylight in spaces depends on
the thickness of extra thermal insulation and transparency of the window glass τv. With the
used combinations of retrofit measures, I can reduce the amount of daylight in referential
spaces from 5,7% to 37,9%.
It is surprising to see that the majority of window manufacturers promote their products only
with the information of the heat transfer coefficient U but the buyer gets almost no
information about the factor τv.