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Keeping heat out
Did you know that external shading is actually the best way to protect your windows from heat transfer? Discover the surprising amount of heat transfer that occurs via these window treatments in our table below.
TREATMENT TYPE |
PERCENT HEAT TRANSFERRED |
Bare Window single Glazing |
100% |
Double Glazing |
90% |
Vertical Blinds sheer curtains |
76% |
Internal Venetians |
55-85% |
Internal Roller blinds |
55-65% |
Tinted Glass |
40-65% |
Specialized Solar film |
20-60% |
Trees light-full shade |
20-60% |
1m Eave on North wall |
30 % |
Roller Shutters |
30 % |
External Awning |
25-30% |
2m deep Pergola with shade cloth or awning |
20% |
North Facing – The most effective option for north facing homes is overhead shading from the high sun.
SEAV recommends:
- Retractable overhead awnings or shutters to allow full winter sun access and summer sun protection
- Alternative option is pergola or verandah with vines or retractable horizontal shading East and West Facing – The most effective option for east and west facing homes is Vertical Adjustable External Shading for low lying morning and evening sun
- For horizontal shading to be effective, the cover needs to project out twice the window height
- For north-west and north-east facing homes, it is also best to use vertically adjustable awnings. Keeping heat in Internal window coverings trap a layer of still air between the glass surface and the window covering, acting as effective insulation, reducing heat flow through the glass.The best option for keeping heat in in the colder months is to trap the air in all directions. This is achieved with the aid of a lined curtain with a pelmet to prevent heat escaping through the top. Double layers of fabric further increase the pockets of air trapping the heat.
This is a feature of the following products:
- Sheer and Lined Curtain
- Honeycomb Blinds
- Double Layer Roller blinds
Discover the amount of heat loss that occurs via these window treatments in our table below. Reference: ES Housing Manual Chapter 5
TREATMENT TYPE |
PERCENT HEAT TRANSFERRED OUT |
Bare Window single Glazing |
100% |
Vertical or Venetian blinds |
100% |
Unlined Drapes or Roller Blinds no pelmet |
92% |
Lined Drapes no pelmet |
87% |
Unlined Drapes or Roller with pelmet |
79% |
Double Glazing |
67% |
Lined drapes with Pelmet |
63% |
Lined drapes with Pelmet and Double Glazed |
46% |