Thermal & Interlined Curtains

Extra lining or interlining adds layers between the room and the glass, giving curtains more body and helping improve thermal comfort at the window.

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How curtain construction affects comfort

Curtain construction changes more than the look. Each additional layer between the room and the glass adds body to the curtain and helps create a more insulating barrier at the window. That is why lined and interlined curtains feel noticeably different from unlined ones, both to the touch and in the room on a cold evening.

Interlining explained

Interlining is a soft layer placed between the face fabric and the lining. It:

adds weight and helps the curtain hang in fuller folds
gives a richer, more luxurious handle
provides structure for some lighter fabrics
helps create a more insulating construction

Different weights and constructions of interlining exist, and the right one depends on the face fabric and the look you want.

Linings compared

Unlined: light and airy, with little insulating value.
Standard lined: adds body, protects the fabric and gives a modest extra layer.
Blackout lined: blocks light through the fabric and adds a denser layer.
Interlined: the fullest, heaviest construction, and the traditional choice for warmth and drape.

Some fabrics can combine interlining with a blackout lining, depending on the construction.

Honest thermal advice

We do not quote heat-loss percentages or energy-bill savings. Real performance depends on the fabric and lining, how much of the window is covered, gaps above and around the curtain, the track or pole position, the glazing and the condition of the window itself. Curtains can make a room feel more comfortable; they do not fix a failing window. For more on comfort at the window, see thermal comfort.

Coverage and radiators

Coverage matters as much as construction. Curtains that stop short, gap at the top or stand away from the wall let warm air circulate past the glass. Returns, a ceiling-fixed track and floor-length curtains all help. Where a radiator sits beneath the window, full-length curtains can trap warm air behind them, so sill-length curtains or a layered blind may be the better answer.

Hardware for heavier curtains

Interlined curtains are heavier and bulkier when open. They need a pole or track with enough brackets and supports for the weight, and enough wall space to stack clear of the glass. We specify hardware from the manufacturer's data rather than guessing. See curtain tracks and poles.

Measuring and fitting

We look at the window, the radiator position, the stack space and the fixing surface, and agree a length and construction that balances comfort, light and practicality. Everything is confirmed at your free home survey.

Honest suitability

Is it right for your window?

Every recommendation comes with a reason. Where something else would serve you better, we say so — and suggest what to consider instead.

Where this works well

Older and period homes Recommended
A heavier construction adds warmth and suits traditional rooms.
Worth knowing: Curtains help comfort but do not repair draughty or failing windows.
Bedrooms and living rooms Recommended
Soft, full drape and a cosier feel on winter evenings.
Draught-prone windows
Extra layers and good coverage help comfort near the glass.
Worth knowing: Performance depends on coverage and gaps as much as the lining.
Windows above radiators With conditions
Sill-length interlined curtains can still add comfort.
Worth knowing: Full-length curtains over a radiator can trap warm air behind them; confirmed at survey.

Where we’d suggest something else

Bathrooms and steamy kitchens
Why: Heavy, layered fabric absorbs moisture and is slow to dry.
The limitation: Interlined curtains are not a practical choice in humid rooms.
Consider instead: Bathroom blinds
Little wall space either side
Why: Interlined curtains are bulky when drawn back.
The limitation: In a tight space the stack can cover part of the glass.
Consider instead: Pleated & cellular blinds

Fabrics and linings

Thermal and interlined curtains build up layers behind the face fabric. The combination is chosen to suit the fabric weight and the look you want.

Standard lining is a separate backing layer sewn behind the face fabric. It protects the fabric from direct sun, adds body and helps the curtain hang and fold consistently.

Blackout lining is designed to stop light passing through the curtain itself. It does not make a room completely dark: light can still find its way around the edges, above the track or pole, beneath the hem and where the curtains meet.

Interlining is a soft layer placed between the face fabric and the lining. It adds weight, fullness and a more insulating construction, and gives many fabrics a richer drape.

The exact fabrics and linings available, and how they behave together, depend on the fabric you choose. We confirm the construction at your consultation.

Tracks, poles and operation

Heavier interlined curtains glide best on a well-specified track or pole with enough supports. The main ways to operate them:

Hand-drawn: the simplest option, and quiet in use. Suits most headings on poles and tracks.
Wands: a slim rod clipped to the leading edge, so you draw the curtain without handling the fabric. No cords involved.
Cord-drawn tracks: a continuous cord opens and closes the curtains. Any looped cord must be held taut by a tensioner or safety device fixed to the wall.
Motorised tracks: available on selected track systems, with control options that depend on the system chosen. Motorisation removes operating cords altogether.

On wide or very heavy curtains, a wand or motorised track reduces handling of the fabric and wear on the leading edge.

Child safety

Where a curtain track is operated by a looped cord, the loop must be held taut by a cord tensioner or safety device fitted to the wall, so it cannot form a hanging loop within reach of children. We fit any required safety devices as part of installation.

Hand-drawn curtains and wands have no looped cords, and motorised tracks remove operating cords altogether, which makes them sensible choices for children's rooms and family homes. See our guide to child-safe window coverings.

Compared with the alternatives

Pleated and cellular blinds

Cellular blinds use a honeycomb construction that traps air within the blind. A compact option where there is no space for heavy curtains to stack.

Blackout curtains

A blackout lining blocks light through the fabric and adds a denser layer. It can be combined with interlining on some fabrics.

Layered window treatments

A blind close to the glass with interlined curtains in front adds another layer and more control.

Related options

Related advice

Questions we get asked

Will thermal curtains reduce my heating bill?

They can improve comfort at the window, but results depend on coverage, gaps, glazing and the window's condition. We do not promise energy savings.

Is interlining worth it?

If you want a fuller, heavier drape and a more insulating construction, it often is. It also needs hardware and stack space to suit.

Can interlined curtains also be blackout?

Depending on the fabric, interlining can be combined with a blackout lining. We confirm the construction for your chosen fabric.

Should curtains cover a radiator?

Full-length curtains over a radiator can trap warm air behind them. Sill-length curtains or a blind are often better there.

More curtain options

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