Get Your Windows Winter Ready - The 6 Most Common Causes of Draughty Windows - Replacement Window Parts Ireland

With the winter months fast approaching, we all want to feel warm in our homes. The last thing you want is to spend money on fuel and have it escape through draughty windows. It’s no surprise that the winter months are the busiest time of year for us. The most common call out we get is about draughty windows. I’m going to share with you my method for diagnosing the cause of draughty windows.

How to Prevent Draughts in Your Windows This Winter

The first thing i check are the openings – the part of the window that opens and closes. The window in this picture is one entire opening. Your windows could have one or more opening sections and one or more fixed sections. Follow the same steps for each opening.

The 6 Most Common Reasons For Draughty Windows

Get Your Windows Winter Ready - The 6 Most Common Causes of Draughty Windows - Window Hinges

1. The Hinges
Top of the list. The no.1 reason for draughts coming through your windows are broken window hinges. Over time, wear and tear, dirt and rust can stop the hinges from opening and closing freely. This causes the hinges to go out of alignment. Which prevents the opening section of the window (the sash) from closing tightly against the seal. Broken hinges can be seen as a gap (at the hinge side) between the sash and the frame seal.

It is so easy to check if your window hinges are the problem. Look at one hinge at a time. Simply open and close the window a few times. Watch how the sash closes against the seal around the frame. The sash should touch the seal when it closes. Push with your fingers against the sash at the corner where the hinge is located. Open and close the window while pushing on the sash. The hinges should pull the sash tightly into place even with you pushing against it.

If there is a gap between the sash and the seal then the hinges are the problem and need replacing. A gap can be as small as 1mm or 2mm or larger enough to fit a rolled up tea towel. (yes i’ve seen all sorts used to pack out the gap from broken hinges) The gap starts small but gets bigger with time. The only cure is to replace the hinges

See here for our range of window hinges.

Top tip: If you are finding it difficult to pinpoint the location of the draught in your window; use a cigarette lighter. Hold the flame an inch or two away from the window. Hold the lighter still at various places around the window. Pay attention to the flame, if the flame is still, no draught, if the flame flickers, there is a draught.

Check out my video above to see this method in action.

Get Your Windows Winter Ready - The 6 Most Common Causes of Draughty Windows - Interlock

2. Interlock
Staying on the hinge side of the window opening, next check the middle of the sash. On nearly all windows no matter the make there will be a set of interlocking plastic blocks at the midpoint of the window opening. These blocks are triangular in shape. One half will be screwed to the window frame and the other half will be screwed to the sash. When the sash closes, the blocks meet and pull the sash in tight to the seal at the middle of the window. These blocks are very important on larger openings (especially on uPVC windows, as the uPVC is quite flexible) If these blocks are not positioned tightly enough, the uPVC sash can flex leaving a gap. Which in turn can lead to a draught.

To test if the interlocking blocks are doing their job, simply push against the sash in the middle of the hinge side. If the sash moves when you push against it the blocks need to be repositioned. If the sash doesn’t move when you push on it, the position is good.

Get Your Windows Winter Ready - The 6 Most Common Causes of Draughty Windows - Window Lock

3. The Window Lock
Next, check how tightly the window closes on the lock side of the window. The vast majority of windows use window espag locks, which are multi-point locks recessed into the sash. The window espag lock have circular rollers locks that lock into metal receivers (keeps) in the window frame. These circular rollers can be adjusted to close the window tighter or loosen it. Insert the correct sized allen key into the roller. Turning one direction will tighten, the other direction will loosen.

Older windows will use cockspur window handles, and will close over plastic wedges fitted to the window frame.

To test how tightly the window is closed, simply open and close the window handle a few times. Pay attention to the seal as you close the window handle. You want the sash will touch the seal and compress against it along the whole length of the lock side. Adjust the roller locks with an allen key if you want your window to close tighter.

Note: the tighter you adjust the circular rollers the more effort it will take to close the window handle. The espag lock is essentially pulling the sash tighter to the seal. Adjust the rollers until you find the middle ground between compression of the seal and operation of the handle.

Top Tip: Listen carefully. Open your window a fraction, take a second to take in the street noise (traffic, dogs barking etc) Now close the window. A well sealed window will cut out the majority of street noise when closed. If you close your window and you can still hear street noise clearly, your window is not sealing correctly. Anywhere you can clearly hear street noise, you will have a draught.

Get Your Windows Winter Ready - The 6 Most Common Causes of Draughty Windows - Seal

4. The Seal
On the majority of windows especially uPVC windows there will be a seal around the window frame and also around the sash. Open the window and check the seal the whole way around. Look for any damage. These seals rarely need to be replaced, only if they have become damaged. Most people think the gap caused by broken window hinges is the seal shrinking.

On older uPVC and aluminium windows, window glazing seals were used to hold the glass or double glazing in the window. These seals can shrink back leaving a gap between the sash and the glazing. Look around each section of glazing in your window. The glazing seals can easily be replaced.

Get Your Windows Winter Ready - The 6 Most Common Causes of Draughty Windows - How the Windows Closes

5. How The Window Closes
This might sound really obvious, but if the sash is not closing squarely in the window frame it can lead to draughts. Check how the window closes against the frame seal. Look around the entire opening when the window is closed. Check that the sash is touching the seal the whole way around. Look at the each corner on lock side of the window. A good guide is to use the weld of the sash. The weld of the sash should line up with the corner of the window frame.

In each corner of the lock side of the window, mark with a pencil the point where the sash touches the seal when the window is closed. This will show you how much the sash is in behind the seal. Ideally the cover should be equally on both sides of the window.

Get Your Windows Winter Ready - The 6 Most Common Causes of Draughty Windows - Plastering
6. Plastering & Window Board
The last items to check are the plastering around the window and the fit of the window board. Check the plaster on the outside of the window as well as the inside if you can. Granted this is easier said than done, especially in apartments etc. A draught can enter through a crack or gap in the external plaster around a window, and travel through to the inside. A draught can enter around an ESB meter box or other window, travel along the wall cavity and in around a different window. Draughts can also enter through the gaps around the window boards. Check the window boards where it meets the window frame. Also check under the window board where it meets the wall.

Fill any cracks or gaps in the internal plaster and window boards with filler, painter caulk or silicone sealant (silicone around the exterior of the window). Do this on every window in your home. This will ensure no draughts can enter around the windows, even if you can’t seal the outside of the windows.

Get Your Windows Winter Ready!

So that’s the method I use every time I’m called to look at a draughty window and hope it will help you to get your windows winter ready! Stay tuned for my video in the next couple of days, in which I will be showing this method in full on a uPVC window. And, if you have any questions about how to stop a draught in your house or are unsure which replacement piece you need, then get in touch!