A large proportion of the heat lost from your home is through the windows; a study by Peterborough City Council suggested that it was as much as 18%. This could equate to a saving of about £130 on your annual heating bill if you were to fit double glazing!

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How it works?

All home lose heat through their windows, but double glazing reduces this by trapping a layer of insulating air between two pains of glass. The effects is that heat cannot pass through so easily and remains in your home. It has the same effect of noise too which is a useful side effect if you live near a noisy road.

There are various types of window to choose from, including triple glazed. There will be styles and frame materials to choose from, but should have most an energy efficiency rating to help guide your choice (although there is no obligation for manufacturers to do so currently). For a list of all windows and their frame material and energy rating, visit the BFRC website.

Secondary glazing is an option where you might not be able to or want to replace your windows. They are a pane of glass fitted inside the existing window frame, and are considerable cheaper, if less effective. They are ideal if you live in a conservation area or your building is listed prohibiting the use of replacement windows.


You will have to comply with building regulations if you are going to replace your windows. And if you live in a conservation areas there are further rules so you must check with your local planning office.

If you are planning to self fit you will need to apply for building control approval.

We will only recommend certified and accredited installers. Ensure that you ask you installer for a certificate to demonstrate compliance to all the relevant rule and regulations when the installation is complete.

Costs and Maintenance

Cost will vary significantly between the styles and materials that you can chose, but as glazing will last for at least 20 years it is well worth ensuring that you fit windows with a good energy saving rating.

You will need to clean your windows. Periodically the seals can fail in a pane – you will see condensation begin to form in the gap between the glass – and you will need to replace the pane. This can generally be done without replacing the frame.


Replacing your windows for double glazing can save you as much as £135 per year. If you were to use secondary glazing you could save £85 per year based on the Energy Saving Trust studies on an average sized 3 bedroom semi-detached home.

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There are other benefits to improving your glazing:

  • Reduced CO2 Emissions – by reducing the amount of energy that you need to heat your home you reduce the amount of carbon that you produce
  • Improved Comfort – by replacing your windows with air tight and sealed windows, draughts will be reduced making your home more comfortable and pleasant to stay in.
  • Noise – Double and triple glazing reduces the amount of noise that can enter your home – particularly useful if you live near a noisy road or airport.
  • Condensation reduction – As double glazed windows are better insulated they do not create large amounts of condensation on the inside of the glass.
  • Lower fuel costs – With less heat loss there is no need to burn so much fuel, thus saving you money!

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What's between the two panes of glass in double glazing?
Very efficient windows might use gases like argon, xenon or krypton in the gap between the 2 sheets of glass.
What keeps the two panes of glass in double glazing apart?
The panes are separated by 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.
Which window frame type would suit my home?
The frame you choose will depend on your home's style and your personal taste, as well as any planning restrictions in your area. The popular material types are; uPVC, wood, aluminium, steel or composite frames.
Do you need extra ventilation if you install double glazing?
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, so it can be a good idea to get replacement windows which have trickle vents incorporated into the frame that let in a small amount of controlled ventilation.
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