GLAZING

  • Up to 40% of a home’s heating energy can be lost and up to 87% of its heat gained through windows. Keep in mind: a low ‘U-value’ helps keep heat in during winter; a low ‘SHGC’ (solar heat gain coefficient) helps keep heat out during summer.
  • Solar access to ‘Living zones’ (living/kitchen/dining/family) during winter is ideal.
  • For north-facing glazing be careful with a low ‘SHGC’ as it might exclude good solar access during winter!!  Perhaps try a high ‘SHGC’ but with adequate shading applied during summer.
  • Locate and size windows and shading to let sunshine in when the temperature is cold and exclude it when it’s hot eg for north-facing glazing in Sydney, an ideal shading overhang or eave would have a ‘projection / height from sill’ ratio = 0.36 (or projection of overhang = 0.36 x height from sill)
  • Use thermal mass (eg concrete floors, brick walls) to store the sun’s heat entering through windows.  This then provides night-time warmth in cold conditions.
  • Locate window and door openings to allow natural cooling by cross-ventilation.