Insulating windows in winter – film, thermal curtains & draught strips
Cold glass and draughts at the window? A few removable measures can make the window area noticeably more comfortable in winter – even in a rental.
How a layer of air helps
Glass and frames pass heat to the outside quickly. A still layer of air in front of the pane – from film, a dense curtain or a closed roller shutter – slows that exchange. What matters is that the air does not circulate, so clean edges and tight closures count for more than thick material.
The options at a glance
1) Insulation film: thin film fixed to the frame with double-sided tape; clear and simple to apply. 2) Thermal curtain: densely woven and lined, reaching just above the floor, with side coverage if possible. 3) Draught strips and excluders: close gaps at windows and doors. 4) Close roller shutters in the evening if you have them. The measures can be combined.
Measure correctly
For film, measure around the outside of the frame and cut generously before tightening. For curtains, width × 1.5 to 2 for folds, length to just above the floor or the sill. For seal strips, check the gap width. Our planner and material calculator help with the sizes.
Do not forget ventilation and moisture
Tighter windows mean less air exchange. Air briefly several times a day, keep vents open and keep curtains clear of radiators so heat is not trapped. If you see damp or mould at windows, have the cause checked instead of just covering it.
Checklist before buying
- Frame and gaps measured
- Lease read: removable solutions only, no drilling
- Window still closes properly after sealing
- Curtain ends before the radiator, vents stay free
- Ventilation plan: brief airing several times a day