It’s mid-September, and while we have still had a lot of warm sunshine so far this month, there is no denying that the evenings and mornings are getting cooler, the nights are starting to draw in, and you are slowly starting to think about hibernating for the winter. Before you do – and there is plenty to do instead of hibernating, but that’s for another blog and another month – take the opportunity of a few warmer and bright weekends to check your windows before the winter well and truly sets in.

Many sash window owners, particularly those with older ones in period homes, complain of draughts during the colder months. There are ways to fix that, without having to fully replace your windows, and there are even ways of finding out if your windows are draughty before those cold easterly winds start to blow. How, we hear you ask. Well…let us tell you.

Checking for draughts

You may already know which windows are draughty after last winter’s Beast from the East. The parts of a window that are most likely to cause problems are:

  • Hinges. Any hinge that is cracked or broken will break that seal, allowing air to come in. Hinges that are out of alignment will also let in a draught. It may not be immediately obvious, so try opening and closing your window a few times paying particular attention to each hinge. What you are looking for are any gaps between the window seal and the hinge. When closed, the hinge should touch the seal. If you find that your hinges are not working as they should then get them replaced before the problem becomes worse.
  • Interlocking mechanism. This is the part of the window found in the middle of the sash. It should sit tightly when closed, creating a seal between the two parts of the sash window. You can check how good the seal is by pushing the sash in the middle section of the hinge, on the inside of the window. If it moves when you push against it, it will need to be repositioned.
  • Lock. Open and close the locking mechanism a few times to check how well it sits and seals the window when locked. You can adjust it if necessary by moving the roller lock. A rule of thumb to keep in mind is that the tighter the roller, the harder it will be to push down on the handle to lock the window, so aim for something that’s manageable without leaving a gap through which air can pass.

The smoke test

A quick way to look for those tiny gaps that are invisible to the naked eye, but which you can feel when that cold wind is howling outside, is to do a smoke test. To do this:

  • Close all windows and doors.
  • Turn on any bathroom or kitchen vents to create a negative atmosphere indoors.
  • Light an incense stick and run it past each window slowly.
  • Look for any signs of the smoke moving, and being drawn inwards in particular (this will be caused by the negative pressure you have created by turning on the vents. If it doesn’t move, then your windows are airtight.

For advice on how to check your sash windows or for any maintenance needs talk to us at Wandsworth Sash Windows. All you need to do is give us a call on 020 3733 3575 to make an appointment or to have an informal chat.

Contact the Wandsworth Sash Windows team

Talk to us – we can help with your bespoke window, door and joinery requirements. Call 02079247303 or email