Abstracted from ASHRAE (1989), with permission
Coefficients of transmission U for wood doors (W/m2·°C)Thickness |
Description |
Winter |
Summer |
||
24 km/h wind 21°C inside temperature |
12 km/h wind |
||||
No storm door |
Wood storm door (50% glass) |
Metal storm door |
No storm door |
||
35 mm |
Hollow-core flush door |
2.7 |
1.7 |
1.8 |
2.6 |
35 mm |
Solid-core flush door |
2.2 |
1.5 |
1.6 |
2.2 |
44 mm |
Solid-core flush door |
1.9 |
1.6 |
1.4 |
1.8 |
44 mm |
Solid-core flush door with single glazing (17% glass) |
2.6 |
1.6 |
1.8 |
2.5 |
44 mm |
Solid-core flush door with insulating glass (17% glass) |
2.1 |
1.4 |
1.5 |
2.0 |
Thickness |
Description |
No storm door |
Metal storm door |
44 mm |
Fiberglass or mineral fiber core with steel stiffeners, no thermal break |
3.4 | - |
44 mm |
Solid urethane foam core with thermal break |
1.1 | 0.91 |
Single Pane |
Double Pane |
Triple Pane |
Plastic domes |
||||||||||
No air space |
5 mm air space |
6 mm space |
13 mm air space |
6 mm space |
13 mm air space |
Single wall |
Double wall |
||||||
No low-E coating |
No low-E coating |
No low-E coating |
No low-E coating |
Low-E coating |
Low-E coating |
Low-E coating |
No low-E coating |
No low-E coating |
|||||
No storm sash |
No shade |
Winter |
6.2 |
3.5 |
3.4 |
2.8 |
2.4 |
2.2 |
1.8 |
2.2 |
1.8 |
||
Summer |
5.9 |
3.7 |
3.5 |
3.2 |
2.9 |
2.7 |
2.2 |
2.5 |
2.2 |
||||
Indoor shade |
Winter |
4.7 |
3.0 |
2.7 |
2.4 |
2.2 |
2.0 |
1.7 |
1.8 |
1.5 |
|||
Summer |
4.6 |
3.3 |
3.1 |
3.0 |
2.7 |
2.4 |
2.1 |
2.3 |
2.0 |
||||
Glass outdoor storm sash with 25 mm airspace |
No shade |
Winter |
2.8 |
2.1 |
2.0 |
1.8 |
1.7 |
1.5 |
1.4 |
1.5 |
1.3 |
||
Summer |
2.8 |
2.3 |
2.2 |
2.2 |
2.0 |
2.2 |
1.7 |
1.8 |
1.8 |
||||
Indoor shade |
Winter |
2.5 |
1.6 |
1.6 |
1.4 |
1.4 |
1.2 |
1.1 |
1.2 |
1.1 |
|||
Summer |
2.8 |
2.1 |
2.0 |
1.7 |
2.0 |
1.8 |
1.6 |
1.7 |
1.6 |
||||
Glass indoor storm sash with 25 mm airspace |
No shade |
Winter |
2.8 |
2.1 |
2.0 |
1.8 |
1.6 |
1.5 |
1.4 |
1.5 |
1.3 |
||
Summer |
2.8 |
2.3 |
2.2 |
2.2 |
2.0 |
1.9 |
1.6 |
1.8 |
1.7 |
||||
Indoor shade |
Winter |
2.5 |
1.6 |
1.6 |
1.4 |
1.4 |
1.2 |
1.1 |
1.2 |
1.1 |
|||
Summer |
2.8 |
2.0 |
2.0 |
2.0 |
1.9 |
1.8 |
1.5 |
1.7 |
1.6 |
||||
Acrylic indoor storm sash with 25 mm airspace |
No shade |
Winter |
2.7 |
2.0 |
1.9 |
1.7 |
1.6 |
1.5 |
1.4 |
1.5 |
1.2 |
||
Summer |
2.7 |
2.2 |
2.2 |
2.1 |
2.0 |
1.8 |
1.6 |
1.8 |
1.6 |
||||
Indoor shade |
Winter |
2.4 |
1.6 |
1.5 |
1.4 |
1.3 |
1.2 |
1.1 |
1.2 |
1.0 |
|||
Summer |
2.7 |
2.0 |
1.9 |
1.9 |
1.8 |
1.7 |
1.5 |
1.6 |
1.6 |
||||
Exterior horizontal panels (skylights) |
Winter |
7.0 |
4.0 |
3.7 |
3.4 |
2.7 |
3.0 |
3.2 |
6.5 |
4.0 |
|||
Summer |
4.7 |
3.2 |
3.1 |
2.8 |
2.0 |
2.4 |
2.6 |
4.5 |
2.6 |
Notes: