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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

PER CENT 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 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 vertical 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

PER CENT 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%