Cheaper fixes before new glass
Seal the frames
Foam strips and sealant around frames stop draughts. See draught-proofing.
Curtains and pelmets
Lined curtains that reach the floor and wrap to the wall, topped with a pelmet, trap a layer of still air.
Use them with the seasons
In winter, open coverings when the sun shines and close them at dusk. In summer, close them by day.
Shade outside
Eaves, awnings, pergolas and deciduous plants keep summer sun off the glass. North-facing glass is the easiest to shade.
Single, double and triple glazing
Single glazing
Most homes- Cheapest
- Little insulation
- Prone to draughts around frames
Double or triple glazing
Upgrade- Can cut heat loss through windows by up to 30%
- Quieter
- Less condensation
- Costly to retrofit across a whole house
- Frames matter as much as the glass
When replacing windows, compare the performance of the whole window, frame included, not just the glass. Start with the rooms you heat and cool most.
Match windows to your climate
| Tropical north | Maximise shading; keep heat out. Glazing that blocks solar heat matters most. |
|---|---|
| Temperate | Let winter sun in on north-facing glass and shade it in summer. |
| Cool and cold | Minimise heat loss: double glazing, heavy curtains and pelmets pay most here. |
Common questions
Up to 40% of a home's heating energy can be lost, and almost 90% of its heat gained, through windows, according to energy.gov.au.
It can reduce heat loss through windows by up to 30%. It pays best in cool climates and in rooms you heat a lot. Curtains, pelmets and shading are cheaper first steps.
Yes, if they are lined, close-fitting, reach the floor and have a pelmet, so they trap still air against the glass.
Sources
Every rate on this page comes from the regulator or the regulated retailer. Last checked October 2026. Prices include GST unless we say otherwise.