Best value for Silver Standard window

[Anonymous]

Hello

Does anyone have recommendations for the best value timber windows which will achieve a u-value of 1.5?

Thank you

Lizzie

[Mark Siddall]

Lizzie,
Have you considered the Rationel Domus was used at Stamford Brook and achieved a U-value of 1.1w/m2K (though I’m not sure whether this is centre pane or whole window). Bulk purchasing issues aside if it was cheap enough for Redrow chances are it should be reasonably ok for you.

Mark

[Anonymous]

Thank you, Mark – they look interesting. I will investigate.

Lizzie

[Anonymous]

Swedish Window Company or Nordan

[Nick Grant]

I'd make a plea for triple with warm edge if you are going low energy.

Reason being surface temperature and condensation rather than heat loss.

If the rest of the fabric is much better then air temperatures will be fine with very little heat input but windows will be cold. If the overall heat loss was higher then more heat would be pumped in (rads under windows!) and the window temps would increase.

We get a bead of condensation along bottom when its say 18-19C indoors and -5 outside – eg first thing in the morning when there has been no heat since the evening. Condensation goes in the eve when we heat the house. Indoor RH usually around 50%.

I don't think warm edge alone is enough to sort it and will try retrofitting some triple units in the existing EcoPlus windows. Discussed elsewhere on the forum.

[Anonymous]

Thank you very much for these good ideas. I have sent window schedules to eight manufacturers and will let you know how the quotes compare.

Lizzie

[Andy Mitchell]

Although energy should arguably be the primary concern for all of us, you may also want to consider the following:
– timber sourcing (FSC Pure arguably gives best proof of sustainability, statements such as 'we only use timber from sustainable sources' are at best questionable)
– use of biocides and which ones in timber treatment and finishes (issues of offgassing etc)
– synthetic (ie petrochemical based) v. plant oil based finishes

[Tom Foster]

Lizzie Lines, can you tell us the results of your window quotes invitation? See http://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=527&page=1#Item_8

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