How to measure your windows for a double glazing quote

How to measure your windows for a quote.

To make the most of our online double glazing quoting service WindowQuoter or to arm yourself with as much pertinent information as possible when approaching a double glazing company, you'll want to be able to take reasonably accurate measurements of your existing windows and doors.

Arm yourself with a good tape-measure - preferable a 2mtr plus size (we're thinking about door heights here or larger windows) and something to record the measurements on.

Remember - these measurements are only to get an approximate quote with. When you're ready for a double glazing company to come and fit your windows, they'll take their own survey measurements (which usually includes taking 3 height and width measurements per window). If you're planning on fitting your own, see below.

For 'flat' windows, you'll need the width and the height, usually taken from between the plastered edges. It's worth measuring each end and basing your quote measurement on the larger figure. WindowQuoter works in cms. If you're approaching a window company directly, although they's prefer cms, they'll probably accept measurements in inches too.

Openers appear with in the overall window dimension; only the number of openers will affect the price of that window.

For a bay window, treat each 'panel' as a separate window and measure each panel.

If you're thinking of replacing a flat window with a bow window, Measure the overall 'hole' the window will be fitted in and then specify the number of facets (steps). Facets are usually equally spaced for aesthetic reasons. Remember a bow window will require a roof as well as a new cill board so costs will be higher. That said, it's amazing the difference a bow window can make to the amount of light allowed into your room.

For doors, both entrance, patio and french - again, you'll need to measure the width and height from the wall plaster edges. If your door has a glazed or solid panel above / at the sides, then include these in your measurement.

There's no real need to go climbing ladders and hanging precariously from the guttering to measure your windows. However, an older property may have one or two surprises which is why we'd recommend getting the professionals in for a supply and fit quote and allowing them to do the final measurement.

The problem comes from when the old windows were installed from the outside on older properties, particularly where there is no cavity. The inner wall can have a smaller hole than the outer wall so that when the frame was put in, it butted up against the inner wall brick.

When replacing these types of installations, the window company will usually have to chisel out the inner brick to match the opening of the outer brick. The window company will have the expertise to carry this out at the time of installation including any remedial plaster work once the hole has been finished.

One last point regarding the actual depth of the frames, if you have an older property, then you may benefit from the wider frame widths (70mm / 65mm) as these are designed to butt up to existing plaster surrounds yet still cover the cavity and extend into the putter wall to the correct depth.

Slimmer frame widths are usually only used in newer properties where plaster lines and cavities were designed around slimmer frames to begin with. Check with your window company what they recommend. Remember, most have had years of experience and most likely will have come up against every eventuality possible.

As tempting as it may be to think you can get away with a supply only quotation, remember the measurements are all down to you. Get it wrong and there's no comeback on the window manufacturer. You could be left with a very expensive pile of scrap upvc. Also, when fitting your own windows, it's worth remembering that it will be up to you to apply to the local council for the installations energy efficiency certificate, which is playing an increasing role in how your home is rated for services, especially when you come to sell your property - now or in the future.

Having your windows manufactured and installed by a window company means that the energy efficiency certificates are taken care of - the window companies having passed rigorous tests to be able to certify their own installations.


*Please note that the above guidelines are only intended to allow homeowners to enter reasonably accurate measurement into WindowQuoter for the purposes of getting an online quote or advising Double Glazing companies of the approximate measurements for initial quoting purposes.

If you're measuring for replacing and fitting windows yourself, you may need to take further advice from the manufacturer before they proceed with your order on the best measurement points, depending on the age and style of the existing windows.

All supply and fit orders should be measured by the companies surveyor, to ensure correctness. This probably won't be the case if you're ordering supply only windows and doors where any mistakes are usually your responsibility.

photo credit: Mulad