Monthly Archives: January 2011

Understand WER’s (Window Energy Ratings)


Rules governing the performance of windows changed in October 2010. Before then windows had to have a U value of 2 (1.8 in Scotland), as from 1st October 2010 the new u value is 1.6 for both England and Scotland, or a WER (Window Energy Ratings) that is C rated or better.

Any contract signed before that date can still have the old values until the end of March 2011, but any contract signed on or since October 1st 2010, must comply with the new regulations.

For years U values were the only measurement being used, but this dint account for energy gain, the free solar gain that naturally enters the building, and not just in the summer months, low sunshine during the spring and autumn mean that lots of solar gain is possible whilst it is still cold outside.

To calculate the heat being lost and the heat being gained is a bit complicated, that’s where Window Energy Ratings come in. Most companies who manufacture windows will by now have tested and results showing the values for their products, A,B,C or worse.

For years 5.8 was used as the u value measurement for single glazed windows, that’s 5.8 units of heat, being lost every hour, for each 1sq metre of glass, for every 1 degree difference in temperature, between the outside and inside)

So if it’s -8 outside and + 18 inside, that’s 150.8 units of heat EVERY hour through a pane that’s just 1metre square!

Standard, air filled “double glazed sealed units” 16, 20 or 24mm sealed units, meant that this figure could be reduced to approx 2.8, a significant reduction, so the new figure of 1.6 is a huge improvement and the government wants to see it reduced again in 2013 by a further 25% to 1.2.

Window Energy Ratings are issued by BFRC, the British Fenestration Ratings Council, they have issued the majority of Window Energy Ratings by licensing specific products, taking into account:

  • The heat loss through the frame material
  • The surface coatings on the glass to reflect or trap energy
  • The air leakage between the moving opening parts of windows
  • Even the amount of sunlight it can expect during the year!

For the record, EST the Energy Savings Trust, only recommends Energy Efficient products, those rated B or better, so they’re the only ones that can legally carry the blue Energy Savings Recommended swing tag logo. This is an important factor to look out for when looking at Window Energy Ratings.

Editors Tip

1) It’s natural to say we will just have A rated then, its better than B or C, and that’s true, however to get to an A rated product some companies have to remove the steel reinforcing making energy efficient but weaker product.

2) Get the specification in writing, because some companies will show you the A rated product, but price for a cheaper one, make sure it says on the contract it’s a C rated product, and check for the permanent marking of the window frames when they arrive.

3) Use the verify button on our web site to check if the company really does have a license for the products they claim.

To find out more about Window Energy Ratings visit the following:

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20 % VAT… more later?


VAT was reduced from 17.5% to 15% to stimulate grow that the end of 2008, it returned to 17.5% at the beginning of 2010 and the new coalition has decided to raise it to 20% from the beginning of January 2011.

Clearly there is a need to fund the government purse, because of the state of the economy and everyone must contribute, however this does raise concerns that the black market will flourish, and this is a major concern to businesses but should it worry homeowners.

Frankly yes, you see when companies operate outside the VAT system, corners get cut, compliance gets missed, jobs don’t get registered, as a result it causes difficulties when its time to sell the property but worse still is non safety glazing may get used and no one will be the wiser, until something dreadful happens.

It has to be worth doing the job properly, and getting full documentation and registration, and with the average contract for replacement windows being around £5k, the extra £125 of VAT just isn’t worth the worry.

Still Ireland is considering 24% VAT, so 20 % doesn’t look quite so bad!


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