Insulating windows in winter: curtain, film or blind?

Cold air at the window, misted-up glass, a room that never gets properly warm despite the heating: many older windows lose noticeable heat in winter. New windows are expensive – but there are simple solutions you can fit yourself, without a tradesperson. We compare the four most common options: sealing tape, insulating film, thermal blinds and thermal curtains.

At a glance

• Seal first: if there is a draught at the frame or sash, new sealing tape helps more than any covering.
• Insulating film suits windows you rarely open – it is cheap, but visible and not suitable for every frame.
• Thermal blinds sit directly on the window sash and can be raised during the day.
• Thermal curtains cover the glass, frame and wall joints at once, feel homely and also work on doors.

1. Sealing tape: the basis against draughts

Before covering the window, check the seals. A simple test: on a windy day, hold a candle or your hand near the frame and sash. If the flame flickers or you feel a draught, the seals are worn or the sash no longer closes properly.

Pros: cheap, discreet, fixes the cause.
Limits: does nothing against the cold glass itself.

2. Insulating film: an invisible second pane

Insulating or shrink films are stretched over the frame with adhesive tape and create a cushion of air in front of the glass.

Pros: cheap, lets light through.
Limits: the window can no longer be opened without removing the film, which makes airing awkward. Adhesive residue can mark some frames, so in rented homes test it on an inconspicuous spot first.

3. Thermal blinds and honeycomb pleated blinds

Blinds with a coated back or a honeycomb structure are fixed directly to the window sash.

Pros: space-saving, can be raised during the day, the window can still tilt.
Limits: the frame and the joints at the sides stay uncovered, so cold air can still flow into the room there.

4. Thermal curtains: warmth with a cosy feel

A dense, multi-layer curtain covers not only the glass but also the frame and wall joints. Drawn in the evening, it forms an extra layer between window and room. During the day you push it aside and let the sun in. A good thermal curtain also dampens noise and keeps out heat in summer.

Pros: covers the largest area, homely, also suitable for balcony and front doors.
Limits: needs space for a rod or track; it should not hang in front of a radiator, so the heat can reach the room.

What to look for when buying is explained in our article thermal curtain or blackout curtain. For fitting on windows and doors, see thermal curtains against draughts.

Which solution suits your window?

Rented flat, no drilling

The thermal window curtain with hook-and-loop tape (280 g/m², three-layer quilting) fixes all round the frame and comes off again without tools.

Keep your existing curtains

Don't want to replace your favourite curtains? The quilted thermal curtain liner (280 g/m²) hangs as an extra layer behind them or works on its own.

Large windows and bedrooms

For large window fronts, a made-to-measure curtain hung close to the ceiling and overlapping the sides is worth it. The Titan thermal blackout curtain combines heat protection with about 90 % light reduction – ideal for the bedroom. You will find all models in made-to-measure thermal curtains.

Balcony and front doors

Draughts are often strongest at doors. Quilted and magnetic models are in door curtains & thermal door curtains. How to pick the right one is explained in thermal curtain for the front door.

Combining works best

These solutions are not either/or: check the seals first, then cover the window. A thermal blind on the sash plus a thermal curtain in front gives two layers of air – especially effective on old, single-glazed windows.

Everyday tips

• Close the curtains as soon as it gets dark, and open them during the day so the sun can warm the room.
• Plan the curtain to end just above the floor and 15–20 cm beyond the window on each side.
• Keep radiators clear: the curtain ends on the windowsill or runs beside the radiator.
• Air the room briefly and thoroughly every day so no moisture builds up behind the curtain.

Checklist

• [ ] Seals checked
• [ ] Window measured – width including side overlap
• [ ] Fixing chosen: hook-and-loop, rod or track
• [ ] Radiator and windowsill taken into account