Double Glazing & Window Regulations

Last updated: 15 Mar 2024

These regulations relate to England and Wales and could differ in Scotland.  It is always advisable to check with your local Building Control office if in any doubt.

Double Glazing & Window Regulations

Always keep in mind that if you reside in a place categorised as a preservation area or your home is a listed building then you might have to find out about planning permission for most kinds of do it yourself venture as these types of properties can fall outside of the regulations for unlisted homes.

These regulations relate to England and Wales and could differ in Scotland.  It is always advisable to check with your local Building Control office if in any doubt.

Windows (Installations and Glazing) - Planning Permissions

You should not usually have to seek planning authorization if you are simply replacing your windows. This includes alternative replacement windows, alternative double glazing and hard patio doors, however with regards to alternative double glazing ensure you conform to building rules which came into force 1st Apr 2002.

Conservatory 2Repairs to existing hard windows, doubled hard units or double glazing windows are normally exempt from planning permission.

Building Regulations - Windows and Glazing

Ventilation and Windows

Windows which are fixed in restrooms, cooking areas or other areas in which vapor is normally created must have sufficient air flow, usually in the form of electric powered ventilators.

Building Regulations - Safety - Windows

Glazing - Replacementsconservatory

Since regulation came into force 1st Apr 2002 any replacement double glazing must conform to building regulations with regards to energy-efficiency, air flow, heat and issues of health and safety.

In particular when fitting double glazing within window areas which come below 800mm from ground level, 300mm from a entrance or a hard entrance area up to 1500mm from the earth, you must fit only double glazing which meets safety standards.

Other safety aspects must be considered when changing windows or installing new windows, including the important matter of escape. Window spaces when suitable replacement windows must be at least the minimum size required for safe means of escape via the windows.

If the windows which were originally installed were over sized it is deemed acceptable to reduce the size of the new windows that you are fitting as long as the size still complies with specifications relating to the means of escape requirements mentioned above.

If changing windows at a first floor level or higher it is recommended that non-escape windows be changed with windows which are considered appropriate for means of escape and of course are in line with minimum window size requirements of not less than 450mm in both width and height.

Exterior Of House With Conservatory And PatioWindows - Energy Efficiency

The objective when you are installing windows is to get the smallest possible u-value, (i.e - the least amount of heat lost through the windows as possible).

Thermal heat loss from windows is calculated by something which is called U-value. Described in more detail, the U-value is essentially the rate at which windows and other materials lose heat.

All homes are now expected to be as energy efficient as possible and new windows should always be fitted with the minimum U-value required to be compliant.  The values for these are listed below:

Miniature House With Various Drafting Items and Plans.Glass U-Values

  • Single glazing - 5.0 U-value
  • Double glazing - 3.0 U-value
  • Triple glazing - 2.2 u-value
  • Double glazing with low e-coating - 1.7 u-value
  • Double glazing with low e-coating and argon filled 1.3 u-value
  • Triple glazing with multiple low e-coatings and xenon filled 0.4 u-value

An added advantage of working with U-Values is that you may benefit from lower fuel and heating bills in particular.  So, there are also financial ongoing benefits to installing new windows which are energy efficient.

The plan is readyBuilding Regulations - Window Installation

When having new windows fitted, it is essential that these are fitted by a competent person and that you obtain certification on completion.  FENSA registered tradesmen are able to provide this documentation.  Failing to gain certification when you have a major piece of home improvement work such as window fitting undertaken could lead to major problems when it comes to selling your home.

Double Glazing Building Regulations

Always keep in mind that if you reside in a place categorised as a preservation area or your home is a listed building then you might have to find out about planning permission for most kinds of do it yourself venture.

Windows (Installations and Glazing) - Planning Permissions

You should not usually have to seek planning authorization if you are simply replacing your windows.

This includes alternative replacement windows, alternative double glazing and hard patio doors.

With regards to alternative double glazing ensure you conform to building rules which came into force 1st Apr 2002.

Repairs to existing hard windows, doubled hard units or double glazing windows are normally exempt from planning permission.

Double Glazing Building Regulations - Windows and Glazing

conservatoryVentilation and Windows

Windows which are fixed in restrooms, cooking areas or other areas in which vapor is normally created must have sufficient air flow, usually in the form of electric powered ventilators.

Building Regulations - Safety - Windows

Glazing - Replacements

conservatorySince regulation came into force 1st Apr 2002 any replacement double glazing must conform to building regulations with regards to energy-efficiency, air flow, heat and issues of health and safety.

In particular when fitting double glazing within window areas which come below 800mm from ground level, 300mm from a entrance or a hard entrance area up to 1500mm from the earth, you must fit only double glazing which meets safety standards.

Other safety aspects must be considered when changing windows or installing new windows.

These include the important matter of escape.

Window spaces when suitable replacement windows must be at least the minimum size required for safe means of escape via the windows.

If the windows which were originally installed were over sized it is deemed acceptable to reduce the size of the new windows that you are fitting as long as the size still complies with specifications relating to the means of escape requirements mentioned above.

If changing windows at a first floor level or higher it is recommended that non-escape windows be changed with windows which are considered appropriate for means of escape.

Of course your windows must be in line with minimum window size requirements of not less than 450mm in both width and height.

window in houseDouble Glazing Building Regulations - Windows - Energy Efficiency

The objective when you are installing windows is to get the smallest possible u-value.

This means the least amount of heat lost through your windows as possible.

Thermal heat loss from windows is calculated by something which is called U-value.

Described in more detail, the U-value is essentially the rate at which your windows and other materials lose heat.

All homes are now expected to be as energy efficient as possible.

New windows you install should always be fitted with the minimum U-value required to be compliant.

The values you should follow for these are listed below:

Double Glazing Building Regulations - Glass U-Values

  • Single glazing - 5.0 U-value
  • Double glazing - 3.0 U-value
  • Triple glazing - 2.2 u-value
  • Double glazing with low e-coating - 1.7 u-value
  • Double glazing with low e-coating and argon filled 1.3 u-value
  • Triple glazing with multiple low e-coatings and xenon filled 0.4 u-value

An added advantage of working with U-Values is that you may benefit from lower fuel and heating bills in particular.

So, there are also financial ongoing benefits you can gain via installing new windows which are energy efficient.

building plansBuilding Regulations - Window Installation

When having new windows fitted, it is essential that these are fitted by a competent person.

You should obtain certification on completion.

FENSA registered tradesmen are able to provide you with this documentation.

Failing to gain certification when you have a major piece of home improvement work such as window fitting undertaken could lead to major problems when it comes to selling your home.

You will likely be asked to provide certification as part of the 'selling your home' process.

Non-provision will undoubtedly slow down your property-sale process.

Need Window Fitters?

If you want to compare quotes from window fitters and double glazing installers quickly and easily, now that you have an idea of double glazing building regulations, why not try Top Tradespeople's free tradesmen quotes services?

You can post a job using our jobs posting form above.

We will then get to work finding you window fitting companies and other window fitting tradespeople to provide quotes for you from our network of UK tradesmen.

Good luck with your window fitting project.