Thermal Curtain Liner

Thermal curtain liner that hooks behind any existing pencil-pleat, pinch-pleat or eyelet curtain — creates the still-air cavity that does the actual insulating (same principle as double glazing), with a fine aluminised coating on the window side to reflect radiant heat back into the room. Our thermal curtain liner installs in five minutes per panel.

Cloth is not the insulator — still air is

People buy thermal linings expecting the fabric to be the insulator, and it is not. Cloth is a poor insulator on its own; what actually resists heat flow is still air. Add a second layer behind a curtain and you create a sealed cavity of air that cannot circulate, and that cavity does almost all the work. It is precisely how double glazing functions, and the physics does not care that one version costs four hundred times the other.

Why a thermal curtain liner beats a heavier single curtain

Which is why a liner outperforms a single thicker curtain of the same total weight. Two cloths with a gap beat one dense cloth every time, and it is why lining an existing pair of curtains is a better spend than replacing them with something heavier.

Aluminised coating: the radiant-heat half of the problem

The face here carries a fine aluminised coating on the window side. That addresses the other half of heat loss: radiant transfer from the warm room to the cold glass, which convection-based insulation does nothing about. A reflective surface returns a meaningful share of that radiant heat to the room. It is invisible from either side once hung.

The cavity has to be closed at the top — the single most important fitting rule

For the cavity to work it has to be closed at the top. A liner hooked behind a curtain on a pole with a gap above it lets warm room air pour over the top, down the glass and out along the floor — the convection loop — and the whole benefit is lost. Hang it on a track fitted tight to the ceiling, or fit a pelmet, or at minimum use a curtain rod with the pole close to the wall. This is the single point that decides whether you feel it.

Installation: five minutes per panel

It hangs on standard hooks through a woven three-pocket header tape, so it fits pencil pleat, pinch pleat and eyelet headings and can be set at three heights to sit just below the curtain top. About five minutes a panel, and it lifts straight off for washing — which matters, because the liner is the layer that takes the condensation.

Sizes and trim

Widths to fit 52, 66, 90 and 108 in. curtains; drops 54, 72, 84, 90 and 108 in., trimmable at the hem. Finish an inch shorter than the curtain so it never shows.

Care

Cold wash on its own, hang to dry, never tumble — heat damages the aluminised layer.

Thermal curtain liner size guide

How to care for your thermal curtain liner

• Cold wash on its own on gentle
• Hang to dry — never tumble (heat damages aluminised layer)
• Do not iron the aluminised face
• Skip fabric softener — degrades the reflective layer

Frequently asked questions

Does a thermal curtain liner really insulate?

Yes — via the still-air cavity it creates behind the curtain, plus an aluminised layer reflecting radiant heat. Same principle as double glazing.

What’s the most important thing when fitting a thermal curtain liner?

Close the top of the cavity. If warm air pours over the top of the curtain, the whole insulation benefit is lost. Ceiling-mount the track, add a pelmet, or minimum pole close to the wall.

Which curtain headings fit a thermal curtain liner?

All standard headings — pencil pleat, pinch pleat and eyelet. Woven three-pocket header tape and standard hooks.

Can I wash a thermal curtain liner?

Yes — cold wash on its own, hang to dry. Never tumble (heat damages the aluminised layer).

Complete the insulation

Pair with your existing linen curtains or blackout curtains, and add a quilted throw for the sofa.