Technical details


When choosing a flat roof window, there are several technical details to consider. Here is a brief explanation of some important specifications:
Ut-value
LT-value
g-value
Rw-value
Clear - opal - solar control

Flat roof window Vitria and iWindow2 & 3

Flat roof window specifications
Flat roof window - Glass type Ug-value(W/m²K)
Insulation value		 LT-value(%)
Light transmission		 g-value(%)
Solar energy transmission		 Rw-value(dB)
Acoustic value
Skylux Vitria Double glazing** Clear glass HR ++ 1.10 W/m²K 77 % 59 % 39 dB
Skylux iWindow2 Double glazing** Clear glass HR ++ 1.00 W/m²K 75 % 52 % 39 dB
Skylux iWindow2 Double glazing** Opal glass HR ++ 1.00 W/m²K 72 % 50 % 39 dB
Skylux iWindow2 Double glazing** Solar control glass HR ++ 1.00 W/m²K 53 % 40 % 39 dB
Skylux iWindow3 Triple glazing** Clear glass HR +++ 0.50 W/m²K 63 % 42 % 41 dB
Skylux iWindow3 Triple glazing** Opal glass HR +++ 0.50 W/m²K 61 % 41 % 41 dB
Skylux iWindow3 Triple glazing** Solar control glass HR +++ 0.50 W/m²K 46 % 33 % 41 dB

Peace and quiet thanks to the best sound insulation!


Sound insulation is an essential aspect to consider when choosing a skylight. Especially when you're bothered by tapping sounds from the rain or outside noise in general. The Skylux iDome is the absolute top when it comes to noise reduction.
Flat roof window type Rw-value (higher = better) Audibility Evaluation
Skylux Vitria & iWindow2 39 dB A conversation with raised voices can still be heard
A normal conversation cannot be heard		 Good
Skylux iWindow3 41 dB Loud sounds can be heard subtly Excellent
iDome 40 dB Loud sounds can be heard subtly Excellent
What does the Rw-value for iWindow mean in everyday life?