Draught proof your home

What are the benefits of draught proofing?

Draught proofing is an easy way to make your home feel warmer whilst reducing your energy bill. According to the Energy Saving Trust, an average home can save £55 per year if all windows and doors are draught proofed and even more if you turn down your thermostat as a result of the improved comfort levels.

An average home could achieve all this for between £75 and £90 if you install the draught proofing yourself.

How to install draught proofing in your home

Watch our step-by-step video

Materials and tools

Transition Belsize recommend the use of the following Q Lon draught proofing strips:

  • Q Lon SBS – for the vertical sides and the base of the window frame
  • Q Lon FS – for the point where sash windows meet in the middle
  • Q Lon 21L – external door draught strip for the sides and top of the window and doors
  • Brush seal strip – for the bottom of doors

This product is most suitable for single glazed sash and casement windows and doors.

To draught proof you will need:

  • tape measure
  • junior hacksaw
  • hammer
  • nail punch, bradawl or drill – for making additional holes in the strips
  • masking tape

Tip: A thick, stiff piece of cardboard can be useful to protect windows when hammering.

Step-by-step instructions

Sash windows

Use the narrow SBS strip for the vertical sides of the window frame:

  • Step 1: First measure the two vertical sides of the sash window
  • Step 2: Cut a strip for one of the vertical sides
  • Step 3: Then fit this into place, checking that it has been cut to exactly the right size. Begin to nail this into place. Be sure to keep a gentle pressure on the strip so that there is a compression on the flexible trim. If there is no compression it will not stop draughts.
  • Step 4: Measure, cut and fit a strip along the bottom of the window.


  • It’s helpful to have another pair of hands to help hold the strips and maintain the pressure on the seal
  • If there’s no-one available to help you could use masking tape to keep the strip in place
  • Only lightly tack the nails to begin with – this allows for adjustment of pressure and position later
  • Measure, cut and fit each strip in place before cutting the next strip

Next use the FS strip for the point where the sashes meet.

  • Step 1: Use a step ladder to raise yourself safely to a comfortable working height
  • Step 2: Measure the sash meeting rail from edge to edge where the sashes meet, ready to fit the FS strip. If there is a catch on the meeting rail the strip may need to be cut into two pieces
  • Step 3: Cut the strip and lay over/across the place where the two sashes meet – so that it sits over the gap but doesn’t prevent the window being opened
Tip: If the two sashes do not meet you can add some self adhesive rubber seal which will help to level and/or fill the gap where the sashes meet. Now nail the FS strip in place.

Remember, the lower sash is draught proofed from the inside, but the upper sash is draught proofed from the outside. If access to the top sash is difficult or there is no frame to attach a strip to, try attaching the SBS strip to the top of the sash on the inside

Draught proofing doors

Use the 21L strip

  • Step 1: First measure the width of the door opening from the outside
  • Step 2: Cut the strip for the top edge. Nail this into place with the door firmly shut
  • Step 3: Next measure and cut the strips for the vertical sides. Again, ensure there is a compression of the flexible trim. The trim expands as the door is opened and is re-compressed on closing.

Energy efficiency grants

You may benefit from a grant for draught proofing and a range of other measures:

If you are over 60 or on benefits you can have your draught proofing installed at a subsidised price through our Care and Repair scheme. For more information please contact 020 7284 5450.

What else can I do?

There are many more ways you can be energy efficient in your home:

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