|
Window type
|
Fraction of area occupied by frame
|
Sheltered
|
Normal
|
Severe
|
|
|
|
|
|
|
|
|
|
|
|
|
|
SINGLE GLAZING
|
|
|
|
|
|
Wood frame
|
10%
|
4.7
|
5.3
|
6.3
|
|
|
20%
|
4.5
|
5
|
5.9
|
|
|
30%
|
4.2
|
4.7
|
5.5
|
|
Aluminium frame
|
|
|
|
|
|
(no thermal break)
|
10%
|
5.3
|
6
|
7.1
|
|
|
20%
|
5.6
|
6.4
|
7.5
|
|
|
30%
|
5.9
|
6.7
|
7.9
|
|
(with thermal break)
|
10%
|
5.1
|
5.7
|
6.7
|
|
|
20%
|
5.2
|
5.8
|
6.8
|
|
|
30%
|
5.2
|
5.8
|
6.8
|
|
|
|
|
|
|
|
DOUBLE GLAZING
|
|
|
|
|
|
Wood frame
|
10%
|
2.8
|
3
|
3.2
|
|
|
20%
|
2.7
|
2.9
|
3.2
|
|
|
30%
|
2.7
|
2.9
|
3.1
|
|
Aluminium frame
|
|
|
|
|
|
(no thermal break)
|
10%
|
3.3
|
3.6
|
4.1
|
|
|
20%
|
3.9
|
4.3
|
4.8
|
|
|
30%
|
4.4
|
4.9
|
5.6
|
|
Aluminium frame
|
|
|
|
|
|
(with thermal break)
|
10%
|
3.1
|
3.3
|
3.7
|
|
|
20%
|
3.4
|
3.7
|
4
|
|
|
30%
|
3.7
|
4
|
4.4
|
