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Is A Rated the Best?

U Value Vs WER Rating!

Marketing Hype or Good Advice?

I'm sure you'll all have heard a PVC salesperson tell you how good their 'A++++++++++++++ Rated' windows and doors are. Have they told you that actually, the 'A++++++++++++++' windows aren't necessarily the best at reducing heat loss - the ultimate way to reduce heating bills? I doubt it.

The Window Energy Rating (WER) scale, similar to that on your Fridges, Freezers etc, is not compulsary for manufacturers and installers, but a few of the big power houses in the industry jumped on the marketing band wagon and, in some respect, have pulled the wool over homeowners eyes. Quite a bold claim, but, let me back this up with my thoughts below:

The standard measure of heat loss in the construction industry is a 'u-value'. Each material will have a 'u-value' which combine to make a full product 'u-value'. Building Control Requirements and Building Regulations are all listed in 'u-values' so that there is one generic term.

Step forward Mr Big Wig who decides that Windows and Doors need their own rating system that is 'easier' to understand for homeowners. *I must point out at this stage, for the sake of cyber-pedants, the WER A+ to G rating system is not a measure of heat loss, but of overall energy efficiency, including solar gain and air leakage (you can google them if you like).* However, as homeowners, we know that the ultimate driving factor is how much the windows and doors are going to lower our heating bills by and how warm they're going to be.

Windows have a requirement to meet or surpass 1.6W/m²K (u-value) and be no less than WER Band C. Doors have a requirement to meet or surpass 1.8W/m²K. Now, this is where I think the real confusion creeps in...

It is possible to have an A+ rated window but only achieve a 1.5W/m²K u-value rating.

Now, to me, this seems perculiar and quite misleading. The stereotypical pushy PVC salesperson (which our lovely team at World Group certainly are not!) will tell you to buy their A++++++++++++ windows because they're the warmest. Incorrect.

If you follow this link, it'll take you to a page that will allow you to view two u-value reports. In 'Report 1' you'll see to the bottom right of the report a 'WER 'A' Rating' and then shortly followed by the '1.3 U Value'. In 'Report 2' you'll see that the WER Rating stays the same, but the U Value drops down to 1.7, which is below the building regulation requirements! This can lead to confusion and some companies won't be too forthcoming with all of the information.

Make sure you know exactly which window will be warmest for you and make a correctly informed decision. If you require further assistance, or if you would like to chat to Matthew or Cliff about boring u-values for hours on end, call the office on 01228 599777.

Posted by: / 24 October 2017 at 09:43 / Comment

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