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DIY window insulation film

Window insulation film works on the same principles as standard double-glazing by creating a layer of still air in front of the glass which acts as insulation - it is attached to the window sash or frame, and not directly onto the glass pane itself.

DIY window insulation kits consist of clear plastic film for attaching to the window sash or frame using double-sided, adhesive tape. They only cost a fraction of the price of double-glazing, yet offer good performance in reducing heat loss and condensation.  These kits are widely available from hardware stores and some online shops.

Window insulation film is designed to only last one heating season and then be removed, but it may remain intact for several years if the windows are in good condition and the film is left undisturbed. Keep in mind that the adhesive tape used on the film may leave a stain if left on for longer than one season.

Tips for installing

  • Installation of DIY window insulation film is relatively easy and only requires a pair of scissors and a hair dryer.  It's also useful to have something to measure your windows with to ensure you cut the film to the right size
  • Ensure that your window frames are dry and that all paint is in good condition to avoid condensation forming inside the airgap. 
  • For wooden windows, applying a bead of sealant like silicone along the glass edge (where the glass pane meets the timber on the inside) all around is a good idea to further reduce the risk of any moisture inside the wood creeping into the air gap.
  • Make sure that your window pane is clean and streak free before you put the insulation up, as you won't be able to clean the inside of the pane as long as the window insulation film is up. 

When DIY window insulation kits may not be suitable

  • Where children or pets are likely to damage the film
  • If maintaining a crystal-clear view is important
  • If wooden frames are in poor condition, leak or are damp, or have flaking paint
  • If the distance between the internal surface of the window frame and the glass pane is less than 5mm (this can be an issue with some aluminium-framed windows).