Double Glazing Explained

Installing or upgrading your double glazing can not only reduce your energy bills, but double glazing can also make your home cleaner, greener, quieter and more energy-efficient, which means you are doing your bit for the environment.

The benefits of double glazing are simple; double glazing saves you money, reduces your energy bills and reduces your carbon footprint.

Save money on energy bills by replacing all the single glazed windows in your home with energy efficient glazing. This could save you around £135 per year on your energy bills.

Reduce your carbon footprint by cutting down on the energy used to heat your home because less heat is escaping through your windows. You will generate less carbon dioxide (CO2) which is what leads to global warming.

Be more comfortable in your home as energy-efficient double glazing reduces heat loss through windows and means fewer draughts and cold spots.

More peace because as well as keeping the heat in, energy efficient double glazed windows can insulate your home against unwanted outside noise.

Reduce condensation double glazing companies kent because energy efficient double glazing reduces condensation build-up on the inside of windows.

The costs and savings of double glazing will be different for each home and each window, depending on the size, material and installer. But on average fitting double-glazing to your home can save around £135 a year on your heating bills, in addition to saving around 720kg of CO2 (carbon dioxide). Double glazing can help to reduce your carbon footprint.

Double-Glazing can save energy and reduce your energy bills

Over 18% of the heat your home loses is lost through the windows. The heat that is lost through these ways means that energy is wasted, and money is wasted. If less heat escapes from your home you can save energy and save money.

Energy-efficient double-glazing cuts heat loss and also reduces noise and condensation problems. Installing energy-efficient double-glazing could mean savings of around £135 on bills annually if whole-house single glazing is replaced with Energy Saving Recommended double glazing.

All properties lose heat through their windows. Installing energy efficient glazing is an effective way of reducing your energy bills and keeping your home warmer and quieter.

Double glazed windows use two sheets of glass with a gap between them which creates an insulating barrier, whilst triple glazed windows have three sheets of glass. Both options can deliver a high level of energy efficiency. It is not the case that you have to use triple glazing to gain the most energy-efficient window.

Energy-efficient windows are available in a variety of frame materials and styles. They also vary in their energy efficiency, depending on how well they stop heat from passing through the window, how much sunlight travels through the glass and how little air can leak in or out around the window.

Some window and door manufacturers helpfully use a window energy rating scheme to show the energy efficiency of their product. This is similar to the one you may have seen on appliances such as your fridge, or washing machine. A-rated windows are the most efficient. To check a window's energy efficiency before you buy, look at the energy label.

The benefits

Smaller energy bills: replacing all single glazed windows with energy-efficient glazing could save you around £135 per year on your energy bills.

A smaller carbon footprint: by using less fuel, you'll generate less of the carbon dioxide (CO2) that leads to global warming.

A more comfortable home: energy efficient glazing reduces heat loss through windows and means fewer draughts and cold spots.

Peace: as well as keeping the heat in, energy-efficient windows insulate your home against unwanted outside noise.

Reduced condensation: energy efficient glazing reduces condensation build-up on the inside of windows.

The costs and savings of double glazing will be different for each home and each window, depending on the size, material and installer. You could save up to £135 a year on your energy bills and up to 720kg of CO2 a year.

Replacement windows and double glazing come in a range of styles and designs and there are particular features you should look out for to increase energy efficiency.

To find the right double glazing windows for your home, ask yourself these questions:

How energy efficient are the windows?

When choosing replacement windows, you can check its energy efficiency by looking at the Energy Saving Trust Recommended logo and BFRC energy label. The Energy Saving Trust endorses any double glazing windows rated C or above. The higher the energy rating, the more energy-efficient it is. Unfortunately, at the moment there is no obligation for double glazing window manufacturers to label their products, however, by opting for a high rated double glazing window you know you will be buying the most efficient.

How many layers of glass do you need?

Double glazing has two layers of glass with a gap of around 16mm between them. There's also the option of triple glazing, which has three layers of glass. A-rated double and tripled-glazed windows are available.

What type of glass is best?

The most energy-efficient glass for double glazing is low emissivity (Low-E) glass. This often has an unnoticeable coating of metal oxide, normally on one of the internal panes - next to the gap. It lets sunlight and heat in but cuts the amount of heat that can get out again.

What's between the panes?

Very efficient double glazing windows might use gases like argon, xenon or krypton in the gap between the 2 sheets of glass.

What keeps the panes apart?

All double glazed windows have pane spacers set around the inside edges to keep the two panes of glass apart. For a more efficient window, look for pane spacers containing little or no metal - often known as "warm edge" spacers.

The BFRC window energy rating scheme checks all the components to ensure the final window achieves the energy efficient standard claimed. This means that you just need to look for the A-G ratings and remember A is best! Alternatively, just look for the Energy Saving Trust Recommended logo which will only be found on glazing that is C rated or above.

Which frame suits your home?

The frame you choose will depend on your home and your taste. For all frame materials, there are double glazed windows available in each energy rating.

uPVC frames are the most common type. They last a long time and can be recycled.

Wooden frames can have a lower environmental impact but require maintenance. They are often used in conservation areas where the original windows were timber-framed.

Aluminium or steel frames are slim and long-lasting. They can be recycled.

Composite frames have an inner timber frame covered with aluminium or plastic. This reduces the need for maintenance and keeps the frame weatherproof

Do you need ventilation?

Because replacement windows will be more airtight than the original single glazed frames, condensation can build up in your house due to the reduced ventilation.

If there is not a sufficient level of background ventilation in the room some replacement windows will have trickle vents incorporated into the frame that let in a small amount of controlled ventilation.

Condensation can sometimes occur on the outside of new Low-E glazing. This is because Low-E glass reflects heat into the home and as a result, the outside pane remains cool and condensation can build up in cold weather - this isn't a problem.

When to improve your Double Glazing

Most homes now have double glazing, but what some people do not realise is that double glazing (like anything else needs to be maintained and sometimes replaced if you have had double glazing for several years.

Mist or condensation inside the glass

If there is moisture inside the panes of glass, it often means the sealant has broken, allowing new moisture in. This means it is usually time to replace your double glazing. "If it's steamed up and there's condensation, it's usually had it and the pane will need to be replaced," says Nick Lowe, of City Windows in Chester.

My windows have changed to a dull yellow colour

The PVC changing colour over time does not mean the quality of the double glazing has been compromised. You can often find specialised paints to re-paint the frames of your windows. Most suppliers nowadays guarantee against discolouring but not against minor dulling and fading.

The hinges on my windows are too tight and it is hard to open the window

If you examine the hinge, you should see a small brass screw. This is the tensioning screw and if you loosen it slightly, it should solve the problem. If this does not work, your local glass shop or double glazing repair company (see local paper ads or Yellow Pages) can usually replace the hinge for you. The hinges on my windows are too loose and my windows fly wide open when opened

If you examine the hinge, you should see a small brass screw. This is the tensioning screw and if you tighten it slightly, it should solve the problem. If this does not work, your local glass shop or double glazing repair company (see local paper ads or Yellow Pages) can usually replace the hinge for you. There is a draught coming through my windows

First, check for a loose handle, slightly bent hinge or a hinge where a screw or rivet has become loose. If it is none of these you may need to replace your double glazing, although it is worthwhile to contact your local double glazing repair first to check if you can have the window repaired.

Double glazing can last for years and years, but like anything else is subject to 'wear and tear'. Before contracting a double glazing company to replace your windows, get a few quotes to ensure that you are getting the best deal, and only go with approved and registered double glazing installers, who offer a guarantee.