Keep Your Home Warm and Your Bills Low this Winter

Blog Post

Keep Your Home Warm and Your Bills Low this Winter

03 Sep 2012

With a cold winter just around the corner, there couldn’t be a better time to invest in Pilkington energiKare™ energy-efficient glazing. However, many homeowners are often baffled by the vast range of glazing solutions available – often confused on what, and how Window Energy Ratings (WERs) work. Here Tony Smith, Business Development Manager at Pilkington UK Limited, shares his expertise to ensure that our glazing purchases pay off.

What are Window Energy Ratings (WERs)?

WERs tell you how energy-efficient your windows are.  The rating system is based on a scale of A-G, with A-rated windows being the most energy-efficient.  Current Building Regulations for replacement windows fitted into existing dwellings only allow windows achieving ratings A to C to be installed. WERs are not applicable to new builds as the whole dwelling should be designed to ensure the building is as energy-efficient as possible and complies with current building legislation.

A WER applies to the whole window (combining the frame and glass performance), not to the individual frame or glass. They’re useful because they take into account the benefits of “passive solar gain” (the free heat from the sun), thereby allowing large areas of appropriate glazing to contribute towards the energy efficiency of a home.

What’s the benefit of knowing a product’s WER?

It allows you to feel confident you’re buying the right double or triple-glazed window for your home, making it easier to compare the energy efficiency of different products.

Installing A-rated windows will help conserve energy and, ultimately, help to reduce heating costs. Most homes lose up to 25 per cent of heat generated through inefficient windows, so it’s easy to see the difference switching to a more energy-efficient window could make.

Why are we talking about them now?

We’re all looking for ways to reduce the cost of energy usage and keep carbon emissions low so this is an opportune moment to be discussing the energy efficiency performance of windows and glazing.

Do my windows have to have a WER?

Ideally yes as it helps you to comply with Building Regulations for replacement windows. Where a WER is given, it also means that the production process has been audited within a factory quality control system, thus ensuring your windows are manufactured to that quality system. Windows offered purely on a low window U value (the older system) may not be as energy-efficient. Even if the supplier is a Competent Persons Scheme Installer member the product manufacturer may not be audited.

How can I verify a WER for myself?

Ask to see the certificate and check with the BFRC (the UK’s national system for rating energy-efficient windows) to confirm that it is listed on the website –

How will using WERs help me comply with Building Regulations?

The ratings mean homeowners can comply with Building Regulations more easily, by comparing the benefits of different products for their projects.

Which products are best to use in which situations?

The most well-known energy-efficient glass product is Pilkington K Glass™. This is the UK’s leading energy-saving thermal glass brand and is specifically designed to prevent heat from escaping through your windows by reflecting it back into your home.

The Pilkington energiKare™ insulating glass unit uses either Pilkington K Glass™, Pilkington K Glass™ S or Pilkington K Glass™ OW for the inner pane and Pilkington Optiwhite™ for the outer pane.

How does Pilkington energiKare™ work?

Pilkington Optiwhite™ is an extra clear glass which allows more sunlight and solar heat to enter your home from the outside.  Pilkington energiKare™ has become one of the leading insulating glass units by using a combination of the above mentioned types of glass. When installed in an appropriate frame a band A Window Energy Rating can easily be achieved.

Can Pilkington energiKare™ insulating glass units be used anywhere?

Yes, they are suitable for a wide range of complete window applications, and can also be installed into most existing windows as replacement glazing providing the frames are still in good condition.

Where can I find a Pilkington energiKare™ installer?

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