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What is FENSA?

FENSA ( ) stands for the Fenestration Self-Assessment scheme. It has been set up by the Glass and Glazing Federation (GGF) ( ) (and other industry bodies, with Government encouragement ( ) in response to the new building regulations.


The secretary of State has issued new regulations through the Department of the Environment, Transport and Regions which will have an impact on the public's purchase of home improvements.

The initaitive follows the Governments commitment to the Kyoto protocol, which aims to reduce emissions of six greenhouse gases to achieve a national reduction of 12.5% between 2008 and 2012, whilst reducing CO2 emission to 20 % below 1990 levels over the next ten years.

The regulations have been in consultation since 2000 and whilst effective from April 2002, ministerial approval was issued on March 5 th 2002 . Because the Government has not issued statements to the public directly, due to the cost, it has been left to the industry to communicate with their customers and as a result, widespread confusion has arisen within the public domain regarding obligations of contractors to the public.

Approximately 27% of national UK emissions of CO2 are caused by the energy consumption of domestic properties. Regulation changes to Document L of the Building Act 1984: Building Regulations, directs that double glazing must achieve a U-value of 2.0 for wooden or UPVC frames and 2.2 for metal frames.

This can be achieved by ensuring that the gap between the glass of the double glazed sealed unit is sufficiently wide and that the glazing incorporates a low emissivity (low E) glass, which is a coated glass, effectively retaining the heat within the household.

Building Control Procedures

Until April 1 st 2002 , replacement windows and doors are not subject to building control or inspection by council appointed officers. The new regulations require all installations to meet improved insulation standards and a certificate must be issued by building control officers for every installation. As there are up to 1.2 million installations per year, it would be an impossible task for building control officers to check all installations. A new scheme has been iniated which allows the hard strectched officers to concentarte on new building work, whilst ensuring that installations comply with regulations.

The replacement window industry has set up a self-certifying scheme known as FENSA and is designed to relieve the otherwise massive pressure on the resources of Building Control Departments.

The object of FENSA is to regulate installers and to self-certify their installations and remove the need for individual installations to be inspected by local building control officers.

FENSA Procedures

Whilst it is not obligatory for installers to join the FENSA scheme, it is strongly recommended by NRWAS & NCAS. The alternatives are to break the law, or to complete onerous and costly inspection procedures.

All installers applying to FENSA must pass a qualifying application procedure which identifies that they will commit to compliance of the new regulations, are willing to offer insurance-backed guarantees and deposit protection insurance.

All installations will be registered with their local building control office through FENSA and a compliance certificate will be issued by the building control office.

It is stated that 1% of all installations will be inspected by a FENSA appointed surveyor on a random basis. The cost of this inspection will be paid for by the installing company. Failure to meet the required standards leads to disciplinary procedures and possible expulsion from the self-certifying scheme.

What Happens On 1st April 2002 ?

All orders for double glazing prior to this date are excluded from the new regulations, provided that they are installed by 1st July 2002.All orders placed from 1st April 2002, must be registered with building control, either directly through individual application, or through the self-certifying FENSA procedure. Before any order is signed, it is strongly recommended that the public asks for evidence of self-certification or that they have building control approval.

Technical Issues

All replacement windows must achieve a thermal U-value of 2.0 (or 2.2, if metal) and a low E glass must be used. Safety rules must also be adhered to as per Document N (safety glazing) - low E glass is available as toughened safety glass. Other elements of Building Regulations must also be complied with - A (Structure), F (Ventilation), B (Means of Escape), J (Combustion Appliances & Fuel Storage Systems), M (Disabled Access).

Entrance doors must achieve appropriate U-value regulations if the glass element is greater than 50% of the total area of the door.


Conservatory installations which were previously exempt from building control continue to be exempt on condition that:The entrance aperture from the main house is not widened - existing exit doors may be used or replacements   and The heating system is self-contained - extensions of a "wet" heating system from a boiler and radiator system will require the structure to comply with building control and planning permission.

As a rule, any proposed conservatory extension which is less than 30m2 or 50/70m2 in area does not require planning permission or building control. In addition, the roof must be glazed (glass or polycarbonate - "at least 75% of area"), be constructed to the rear of the property (outside of frontage sight-lines) and outside of conservation areas. The conservatory must be at ground level and under 4m in height and at least 2m from furthest boundary line (rear of garden). Previously added extensions to the original construction determine planning permission & building control for a conservatory. Listed buildings always require planning permission & building control for conservatories.

Repercussions for Non-Registered Installations

All home improvement installations which require building control approval must be identified and submitted to FENSA from 1 st April 2002 .

This information may be conveyed electronically or manually on a weekly basis to FENSA. This information is then passed to Building Control who will issue a compliance certificate directly to the home owner.

This certificate is vitally important to any future sale of the property, as without it, sales will be at least held up or at worst unable to proceed. At the point of pre-sale contract, purchasers Solicitors will have to include this documentation in their usual search procedures.

In the same way that a sale falls through because a seller has not complied with planning permission or building control regulations on an extension or renovation to a property, the same issues will occur with the new regulations regarding Document  L.

Geographical Limitations

The new regulations apply to all areas of England and Wales from 1 st April 2002 .

Scottish and Northern Ireland Assemblies are in consultation and existing rules in those areas are maintained until notified.

Future Improvements - Window Energy Rating

Changes to Document L consider the upgraded performance of the glass unit within window frames and it is the U-value calculation of the glazing that is important to the current changes.

As energy is transmitted through the entire window (both ways), which includes the actual frame itself, it makes sense to take the frame performance into account to improve future heat loss initiatives.

To this end, a rating scheme known as The Domestic Window Energy Rating (DWER) has been introduced by the British Fenestration Rating Council. This organisation is working to produce pertinent figures and a rating system to take account of solar heat gain, light transmittance and air infiltration.

In the future, it is believed that all windows, including their frames, will have a DWER rating, which can be used to compare performance between manufacturers more easily

Such an initiative will further the UK Governments commitment to the Kyoto agreement and will help the consumer to identity performance in a way which is available currently with domestic appliance energy performance.

Further details are available from the British Fenestration Rating Council at: 

Useful Contacts

Details about the changes to Document L and Building Regulations are available from the Department of the Environment, Transport and Regions at the following web site:


Window Energy Rating
The following is the web site of the British Fenestration Rating Council

Building Control
The following is the most comprehensive web site regarding building control and planning issues and has many links to Building Control Offices throughout the UK and other organisations


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