Do thermal curtains really keep heat in?

Yes, when they are fitted to trap air. Up to 40% of the energy used to heat or cool a home is lost through windows, according to Sustainability Victoria. A heavy curtain that reaches the floor, runs past the frame and is sealed at the top by a ceiling-fixed track or a pelmet stops warm room air from cooling on the glass.

Are thermal curtains worth it over blockout?

For cold rooms and hot west-facing windows, usually. Our thermal curtains add an insulating back to a blockout fabric, at 360 gsm against 280 gsm. An 1800 mm wide, 2400 mm drop S-Fold pair is $299 in thermal and $236 in blockout.

Do thermal curtains help in summer?

Yes, on windows that take direct sun. Close them before the sun reaches the glass, especially west-facing windows in the afternoon. Shading outside the window works better still, but curtains are the cheapest step.

Why is there condensation behind my curtains?

Because they work. The curtain keeps warm, moist room air away from the glass, so the glass gets colder and any moisture that reaches it condenses. Open the curtains during the day, wipe the glass and ventilate wet rooms to stop mould.

Do thermal curtains work?

Yes, if they are fitted to trap air. Up to 40% of the energy used to heat or cool a home is lost through windows, according to Sustainability Victoria. A thermal curtain that reaches the floor, runs past the frame on both sides and is sealed at the top by a ceiling-fixed track or pelmet keeps that heat in. Ours are 360 gsm; an 1800 mm wide, 2400 mm drop S-Fold pair is $299 including GST.

How they work

Cold glass cools the air next to it. That air sinks, spills out at the bottom of the window and pulls warm air from the room down the glass behind it. A curtain only stops this loop if air can’t get round it: across the top, down the sides and under the hem.

Fit them so they work

Top: fix the track to the ceiling, or add a pelmet above the track.
Sides: extend the track past the frame by about 150–200 mm each side, so the curtain covers the reveal.
Bottom: choose “touching the floor” or puddled, not 10 mm off the floor.
Timing: close them at sunset in winter, and before the sun hits the glass in summer.

Thermal vs blockout

	Blockout	Thermal
Fabric	Triple-weave blockout	Blockout with an insulating back
Weight	280 gsm	360 gsm
Light	Stops almost all light through the fabric	Stops almost all light through the fabric
1800 × 2400 mm S-Fold pair	$236	$299

Both block light. Thermal is the one to choose for single-glazed windows, cold bedrooms and west-facing glass.

Condensation and mould

A good thermal curtain makes the glass behind it colder, so condensation can increase on single-glazed windows. Leave a small gap between curtain and glass, open the curtains during the day, wipe the glass on cold mornings and run the bathroom and kitchen fans. Mould on the back of a curtain means it has stayed damp for too long.

Sheer by day, thermal at night

On a double track, a sheer at the front or back gives privacy and daylight during the day, and the thermal curtain closes at night. Order each curtain to the same width and drop.

Thermal curtains Blockout curtains

Prices include GST and were checked on 29 October 2026. They come from the same calculator as the product pages.