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As well as keeping your home warmer and reducing noise, you’ll notice a saving on your energy bills from installing double glazing. If you install A++ rated windows in your home after having single glazing, you could save up to £120 year on your energy bills. The Energy Saving Trust has more information.

Whether you’re hiring a professional to replace your double glazing or are considering DIY, it’s a good idea to know how to fit a double glazed window.

You need to start by assembling your window. Fit any handles and cut the outer sill to size by measuring the outer wall depth. Then, screw the outer sill to the window frame and attach the frame fixers. Screw the ventilation grilles onto the inside of the frame and fix the vents on.

Next, you need put the window into place, using spacers to wedge it in. Use a spirit level to check it’s level horizontally and vertically, adding extra spacers if needed. Then, fix the frame into place at each fixing point using a drill, wall plugs and screws. Measure and cut the interior sill, and check that it’s level, adding spacers if needed. Then fix it using screws, masonry nails or adhesive.

Finally, fill in any wide gaps with foam filler and small gaps with sealant. You can get interior and exterior trims to cover these up, making your window look neat and professional.

You can only repair blown double glazed windows in the sense that you can replace the sealed unit (the glass part of the window) instead of having to replace the entire window.

When a double glazed window is blown, it means that the seal around the window has failed and is now letting air in and out. Often the first sign that the sealed unit has blown is condensation on the inside of the window, which is annoying since there’s no way to get rid of it! When your sealed unit has blown, you’ll be losing heat out of the window, meaning you could be spending more on your energy bills.

As a temporary fix, you could see if you can buy a misting repair kit online, but the condensation will eventually occur again as the air gets in. The best thing to do is ask a window installer or glazier to replace the sealed unit for you.

It's simple to replace the glass in a window – the specialist will remove the beading around the window, remove the blown glass from your window frame and set it to one side. They will then clean up around the frame before adding spacers in, then fitting the new sealed unit into the frame. They’ll make sure it’s a snug fit before replacing the beading back around the window to secure it.

There's no reason to put off repairing a blown double glazed window since the cost is generally much less than replacing the entire thing. A sealed unit with installation costs an average of £100, whereas a completely new window will cost around £400. You’ll soon notice that it’s less draughty and will be able see out of your window once you’ve had the blown glass replaced.

Coloured double glazing windows are more expensive than white ones, in general. uPVC is the cheapest material to use for double glazing, and white is the standard colour. But there are endless possibilities in terms of colours you can have, and they do come at additional cost.

Some people choose to have coloured double glazing that matches or opposes the colour of the exterior of their house. Another popular option is a woodgrain effect, which from a distance looks just like more expensive timber windows. The best thing about a wood effect is that you can have the stylish look of wooden windows without the maintenance, and they should last longer.

While coloured double glazing is more expensive than white ones, it doesn’t have to break the bank. The best thing to do is get in touch with a range of window companies and ask them to come round to give you a quote. They should be able to offer you brochures or links to websites of different brands of windows that offer coloured frames. From there, you can decide on the installers you liked most and the brand you preferred.

It’s worth bearing in mind that it’s not always best to go with the cheapest coloured windows. While there lots of good, inexpensive options out there, sometimes very cheap windows won’t be good quality and may not last as long as other slightly more expensive brands. Speak to your installer about guarantees that may come with the windows and how long they would expect them to last before making your final decision.

uPVC is unplasticised polyvinyl chloride. It is a favourite amongst homeowners and manufacturers for its cheap production cost and excellent benefits. uPVC is used for window frames, conservatories and doors. In fact, uPVC can be three times cheaper than wooden frames and is also the most energy efficient option.As well as this, uPVC is now available in a range of colours other than the typically seen bright white finish. It can also be recycled, is durable and resistant to changing weather conditions.

Using a Fensa registered installer isn’t compulsory but it helps to protect you from cowboys and rogue traders. It will also make life a whole lot easier in regards to Building Regulations. Replacement windows must meet a certain energy efficiency rating and once fitted you need a certificate to show your installation complies. By using a Fensa registered company they’ll issue this certificate, otherwise you’ll need the council to look at the new windows.

• The glass has smashed from an impact such as a stone hitting it from a lawnmower
• You have been broken into and suspects used the window to gain entry
• The glass has blown (lost its airtightness) from constant water build-up around the seals, which is common in bathrooms
• Extreme weather or pressure changes have caused a crack

1. Including the beading (the plastic and rubber seals around the windows that can be removed), measure the width of the window frame.
2. Do the same for the height of the window, making sure you include the beading.
3. Then, take 10mm off each measurement, and you have the approximate size of your glass.

Accidents happen, and sometimes windows get broken. And that will lead to you wanting to replace just the glass in your window, rather than the whole frame. Also, as windows get older they can mist up on the inside, which means that the unit has ‘blown’ - so you’ll also need to replace the glass. But how much is it to replace the glass in a window? Luckily, if the frame of your window is in good condition, there’s no need to replace it, and this will reduce the cost. For an installer to fit a new pane of glass in a single glazed window, the average cost is £100, while a replacement double glazed sealed unit will cost an average of £110. Of course, as this is an average, if your window is very large you may spend more, and if your window is very small the price may be less. That's why it’s important to get a range of quotes so you can compare costs and get the best price. If you’re good at DIY, you may feel confident enough to have a go at replacing the glass in your window yourself. In that case, the cost of sealed unit and any other materials you need will cost an average of £57. It’s a significant saving, and if you think you can do it, then give it a try. However, if you’re in any way unsure, it’s best to leave it to the professionals. A window installer will be able to replace the glass in your window in less than an hour. Even though it costs more for a professional to do it, if you get it wrong and have to start over it will cost you more in the long run.