BFRC has officially launched the applications process for the first ‘A++’ band in England & Wales for Window Energy Ratings (WERs).
There will be four months for window companies to develop new ‘A++’ product as the first licences will not be issued until 1st October 2015 – with the first ‘A++’ product being launched shortly afterwards.
BFRC follows the 10 point band cut offs illustrated in section 4.2 of Approved Document L1b'. The new ‘A++’ rating will be no different, with ratings starting at an energy index value equal to or greater than +20. This means any
BFRC ‘A+’ rated product which achieves 20 or more can be upgraded to an ‘A++’ for an administration and verification fee of £100 (ex VAT).
Alternatively, manufacturers can also apply for new ‘A++’ licences. All applications must be accompanied by a simulation report and can be made either directly to BFRC or through an Independent Agency.
These new ‘A++’ licences are available both as Simplified Energy Licences (SELs) and Detailed Energy Licences (DELs).
“The launch of the BFRC ‘A++’ ratings band – the first in the country – reinforces the message that BFRC is driving technological developments that give homeowners the latest and best in energy efficient windows,” comments
BFRC managing director Chris Mayne. “And contrary to some ill-informed comment within the industry ’A++’ rated windows will not cause homes to overheat.”
‘A++’ and the Overheating Misconception
Overheating in a domestic situation happens when the internal room temperature becomes higher than the comfort level, and cannot be reduced by simply opening the windows. It can be caused by two factors:-
The first is high external ambient temperatures, which can lead to high internal ambient temperatures due to heat conduction through the building envelope (including, but not limited to, windows).
But ‘A++’ (and ‘A+’) windows have significantly lowered U values than lower rated windows, so they will reduce the amount of heat being transferred into the home from outside. With existing glass coating technology, there
is a hard physical upper limit to solar gain performance that cannot be exceeded, so the only way to achieve higher ratings bands is through lower U values.
The second cause of overheating is excessive solar gain - particularly on south facing elevations.
It is expected that all ‘A++’ windows (and about 70% of ‘A+’) use triple glazing, with two panes of low-e coated glass. Their solar gain factor is significantly lower than the equivalent double glazed window.
So all BFRC ‘A++’ rated windows (and the majority of ‘A+’) will actually help to reduce overheating during the summer months. In the winter they will help keep the home much warmer.
“A further benefit to ‘A++’ windows is their lower U values give warmer internal surfaces effectively eliminating the risk of internal condensation,” adds Gary Morgan BFRC technical director.
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