The Need

Energy cost

Traditional sources of energy are becoming scarce and the cost of developing alternative supplies from renewables or nuclear will be high.  Energy prices will therefore continue to rise and impact on budgets. 

Regulation

Building Regulations provide a set of legal requirements for building work.  Approved Document L covers conservation of fuel and power. This sets strict standards of energy efficiency for new buildings and those undergoing renovation or upgrade. Building components such as windows must achieve minimum thermal ratings.  The thermal efficiency of a window can be defined by a Window Energy Rating (WER) or a whole window U-value. 

Exemptions apply to buildings of special historic or architectural value, but there is a requirement to improve energy efficiancy as far as is reasonably practical.

The regulations permit the use of low-e secondary glazing.

Energy Performance Certificates

An Energy Performance Certificate (EPC) is required whenever a building is constructed, sold or rented under the European Union’s Energy Performance of Buildings Directive. The certificate identifies the performance of the building and provides cost effective recommendations for improving the energy rating but without obligation.

A building with a poor EPC is likely to be less attractive to a buyer or tenant.

Secondary Glazing can provide an effective and often fast track solution.

Carbon reduction commitment

The Climate Change Act 2008 requires a reduction in CO₂ emissions of 80% against 1990 levels by 2050.

Buildings account for approximately 40% of the UK’s total carbon emissions of which about half comes from non-domestic buildings.
Government Carbon Reduction commitments will not be met by reducing energy requirements for new buildings alone. The very large number of existing buildings will also need more energy efficient fittings and much improved insulation if the targets are to be met.

More than 80% of today’s buildings will still be in use in 2050.

Secondary Glazing allows the embedded energy of existing windows to be retained.

Why Use Secondary Glazing?

• Secondary glazing is not subject to regulation apart from Listed Building Consents.  

• Overall efficiency with low-e glass compares well with new windows

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• Recommended by Heritage bodies and regarded as an acceptable adaptation in PPS 5 Planning for the Historic Environment

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• Provides a simple way for leaseholders to improve insulation levels and can be demounted, if required, at the end of  the tenancy.

Selectaglaze performance

The Selectaglaze range of secondary windows has been assessed by the Centre for Window Cladding and Technology (CWCT) in combination with existing single glazed metal and timber windows at various air spacings (cavities). For comparison purposes the calculations are based on the British Fenestration Rating Council’s standard window size, 1230mm wide and 1480mm high.

* The range of values reflects differing window styles and outer window construction.

How Secondary Glazing provides thermal insulation and draught proofing