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FENSA rules for replacement windows

Since April 2002 the replacement of windows and doors has been subject to Building Regulations and a householder can either apply for Building Regulations approval or allow the installation company to deal with the issue through its membership of FENSA. This section explains what FENSA is and what the advantages are of using FENSA instead of a Building Regulations application.

The abbreviation FENSA, refers to the FENestration Self-Assessment Scheme

FENSA for replacement windowsGlazing in newly built properties has for many years been subject to Building Regulations approval but in April 2002 replacement glazing in existing residential properties was brought within the scope of Building Regulations. For new buildings where a planning application and building regulations approval are generally sought at the same time, the situation has changed little. But bringing the vast number of replacement glazing installations each year (around two million in 2010) into existing residential properties under the scope of Building Regulations required another organisation to be formed. FENSA, now with over 9,000 member companies, was formed to administer the bulk of the applications otherwise local councils probably would simply not have coped with the volume or work.

FENSA – Selling your property

When selling your property, your purchaser’s solicitors may ask for evidence that any replacement glazing installed since April 2002 complies with Building Regulations. There are currently two ways to prove compliance: –

• A FENSA certificate showing that the work has been carried out by an installer who is registered with FENSA or a similar body
• A certificate from the Local Authority Building Control stating that the installation has been approved under Building Regulations

Advantages of using FENSA
  • FENSA registered businesses are vetted by taking consumer and trade references together with financial checks. They must have at least £10m Employer’s Liability and £2m Public Liability Insurance. Their order forms must include a 7 day cooling off period and any guarantees clearly explained.
  • Contracts for all installations carried out by FENSA registered installers must include a 5 to 10 year guarantee which is covered by an insurance backed warranty and deposit protection insurance.
  • FENSA is trusted by all Local Authorities and the Government.
  • All FENSA registered companies are continuously re-assessed by an independent inspection body to ensure consistency of Building Regulation compliance.
  • Using FENSA is cheaper and easier using than your Local Authority Building Control department.
FENSA: The main regulations affecting the installation of windows and doors include: –

Approved Document A: Structure,

Approved Document B: Fire Safety, Read More..

Approved Document F: Ventilation, Read More…

Approved Document L: Conservation of Fuel and Power, read more…

Approved Document M: Access to, and Use of Buildings, Read More…

Approved Document N: Glazing – Safety in relation to impact, opening and cleaning, Read More…

FENSA – General Rules

As a general rule, the building should not end up after the installation with a worse level of compliance with Building Regulations than before the installation. For example, if the existing windows had trickle vents – so must the new ones, window openings cannot be made smaller than before and windows fitted with side opening casements cannot be replaced with windows fitted with just top opening casements above fixed panes.

FENSA does not apply to new build properties, commercial buildings, caravans, holiday lets not occupied for more than 10 months of the year, conservatories or porches. Building Regulations may still apply to these buildings but should be dealt with under the Local Authority Building Control process.

FENSA, Energy Efficiency and Window Energy Ratings

It is claimed that at least 25% of the heat in your house escapes through your windows and doors, so having energy efficient windows installed not only creates a warmer environment in your home together with lower heating bills – it is also good for the environment generally. The Government’s commitment to reduce emissions and reduce the potentially harmful effects of global warming is at the heart of legislation requiring that newly installed replacement windows and doors meet minimum standards of energy efficiency.

Window energy ratings let you know how energy efficient replacement windows are, based on a scale of A to G in the same way that refrigerators and other household appliances are rated. They were initially introduced in 2004 by the British Fenestration Rating Council (BFRG) which is run by the Glass and Glazing Federation (GGF), though schemes have also been developed by other organisations.


What is meant by U Value?

U value is a measurement of heat transmission through a material and the lower the U value, the less the amount of heat it permits to be transmitted through it, or in other words, the greater the material has resistance to heat. This means that a material with a low U value is proportionately better at insulating than a different material with a higher U value.

U value is expressed or calculated as W/m²K – watts per square metre Kelvin. Watts, being the measurement of energy, m² means that the U value is expressed per square metre of insulating material and Kelvin being a temperature scale commonly used by scientists.

If a window has a U value of 1, for every 1 degree of temperature difference between the inside and outside, there would be 1 watt of energy flowing through (or lost) per year, for each square metre of its surface.