Glazing U Value not making a big impact?

MB1380 · Posts: 2

Hi there, I have been working on a building which contains a lot of glazing (80% +) and while calculating a BER Rating i used two different U Values for comparison and found there was not much of a change between the two.

To test this i drew a rectangular building 80m x 50m x 8m with 100% glazed walls and used 1.1 as the glazing u value resulting in a C2 530 Kwh/m2/yr

I then changed this U value to 3 and expected a dramatic drop in rating but still got a C2 with 540 Kwh/m2/yr

Can anyone explain why such a poor U value in a 100% glazed building is not resulting in a larger drop in the rating?

Thanks in advance.

Andrew Bairstow · Site Admin Posts: 343 Location: Birmingham, UK

Hi
That's a pretty big building so the perimeter: area ratio is going to be quite small and thus heating (and cooling due to solar gains/glazing) is going to represent a small part of the energy/co2 requirement. Try something smaller and you should see more of a difference but bear in mind that other inputs (such as activity) will have an impact and many inputs such as glazing will cause gains and losses and the overall balance of one change may overall be fairly insignificant.
Regards
Andrew

Shortcuts

Login