Passive Design

Designing the building and the spaces within it to benefit from natural light, ventilation and even temperatures.

Internal shading

Internal shading can be provided using curtains and blinds.

Internal shading is less effective at reducing solar heat gain than external shading because the solar radiation has already come through the glass.

The shading absorbs the radiation, and while a small amount of heat is reradiated back to the outside, most remains within the interior space.

Internal shading can be a useful device when:

  • the sun penetrates for only a short time
  • heat build-up will not be a major problem
  • windows can be left open adjacent to them
  • it is required to reduce glare.

Internal shading options

  • Curtains, when drawn, significantly reduce light but reduce heat gain by only a small amount. They also reduce ventilation and block views.
  • Venetian blinds and vertical blinds can be used to adjust the amount of incoming light while retaining views but they reduce heat gain by only a small amount.
  • Roller blinds and other types of window blinds reduce the light admitted but also reduce the heat gain by only a small amount. They may also reduce ventilation and block views but some types of blinds provide two adjustments: one setting provides partial light blockout, the other setting provides full blockout. Blinds may be motorised for high level windows or roof lights. They can be made from a range of sun filter fabrics to suit the desired level of light, view and shading.