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Central Glass and Windows range of high security Composite Front and Back Doors look and feel like traditional timber doors and are available in a wide range of colours, styles and glazing options

Central Glass and Windows are suppliers and installers of glass. Being experienced glaziers, we understand how critical it is that glass is glazed correctly to give the right integrity and insulation values.

The environment is hostile and its effects can be catastrophic for both life and property.

It is therefore critically important that the specification, selection and installation of your glass are all carried out with close attention to detail.

Technical information and support is available from our office on 01782 215240

Obscure Glass

Central Glass & Windows offer a full range of Obscured Glass designed to heights quality and standards.

U-Values Information

The u-value is the measurement of heat transmission through a material or assembly of materials. The u-value of a material is a gauge on how well heat passes through the material and the lower the u-value, the greater the resistance to heat and therefore has a better insulating value.

The u-value is generally used in the building and construction industry to specify assemblies of components, which provide a suitable insulation and energy efficiency value. U-value is expressed in units of W/m2 and relates to the amount of heat lost in watts (W) per square metre of material.

Basically, if a wall material has a u-value of 1.0W/m² K, for every degree of temperature difference between the inside and outside surface there would be 1 Watt of heat energy flowing through each meter squared of its surface.

The lower the u-value means less heat loss, better insulation and effective lower fuel bills. Building regulations regarding the specifying of u-values has become very stringent over the past 10 years or so to give buildings better insulation and reduce heating due to global consumption.

  • A standard double glazed unit with 20mm air gap has a u value of 2.8 W/m2.
  • A standard double glazed unit with 20mm air gap and 1 pane of low e glass has a u-value of 1.8 W/m2.
  • A 225mm solid brick wall with 10mm mortar joints has a u-value of 2.0 W/m2.
  • Typical cavity wall with no insulation has a u-value of 1.6 W/m2.

When quoting u-values it is essential to note whether the value quoted is for an individual material or a complete assembly. A window for example will have the frame, the glazing, and the sealants, which may be a higher or lower u-value than the glass alone.

Assembled materials can have their u-value reduced considerably by adding insulation. Insulated plasterboard can be applied to the inside face of a brick wall to considerably reduce the u-value of the structure. Glass can have special thermal coatings applied, which can allow the heat into the building but restrict the flow of heat out of the building.

Low e glazing has become very popular over the last few years, as glazing in a building is where large amounts of heat can be lost making the whole building less thermally efficient.

The cavity between the double glazed units can additionally be filled with a gas such as argon, which is denser than air alone, again lowering the u-value and increasing the insulation.

FENSA Information

FENSA – Building Regulations and Your Windows

On the 1st April 2002 the replacement of windows and doors came within the scope of the Building Regulations for England and Wales; therefore any replacement of windows and doors in your home are subject to the requirements of these regulations.

This was one of a number of changes designed to improve the thermal efficiency of our homes and to assist the government in meeting its commitments to reduce CO2 emissions under the Kyoto Agreement. It will also mean that our homes are warmer and use less energy.

You can meet your commitments under the Building Regulations by either:

Applying for approval to replace your windows and doors through your Local Authority Building Control Department. By using a contractor/installer who is registered with FENSA.

The FENSA Scheme was set up by the Glass and Glazing Federation with the co-operation of the Office of the Deputy Prime Minister (the government department responsible for Building Regulations) as a Competent Person Scheme. This scheme enables registered businesses to certify through FENSA that the installation meets the current Building Regulations. FENSA will register your installation electronically with your Local Authority and send you a certificate which records that your installer has certified that the installation meets the appropriate Building Regulations.

A FENSA registered business is required to understand the regulations and be capable of installing a product in your home which meets requirements. He will therefore advise you on the design of your windows and doors and see that the installed windows have the correct thermal performance.

The installer is not permitted to fit non-compliant products. If these are fitted you will have committed an offence under the Building Act 1984, as well as possibly putting yourself and others at risk. It is also a requirement that the installation is registered; it is not an option to ignore this part of the process.

If your windows are not registered directly with your Local Authority or by a FENSA Registered business then you will have problems when you sell your home. The purchasers’ solicitor will require evidence, via the registration, that the windows and doors conform to the relevant regulations.

FENSA also organise, on a random basis, the inspection of a number of installations, through inspection agents, to ensure that Building Regulations are being met. You may therefore be contacted by one of the inspection organisations.

A FENSA registered business is also required to offer you the opportunity to purchase an insurance policy directly from the insurance provider, to cover the window and door guarantee should the registered business cease to trade.

The registration of the installation with FENSA does not imply any warranty as to the quality of the product. In registering the installation the installer is certifying that the job conforms to appropriate Building Regulations.