Time I took the trouble to understand Air Flow windows - www.dwell-vent.co.uk with www.howarth-timber.co.uk. Can anyone explain?

There is a section of Supply Air windows in "Low Energy Buildings and District Energy Systems" by L.D. Danny Harvey in which it is reported that they can achieve a seasonal U-value of 0.6w/m2K.

Mark
P.S. It's a bloody good book (though you may want to get a second hand copy, or take a trip to the library as it's quite pricy.)

Are there any detailed drawings available for the construction of these windows. I've got access to a machine shop and was hoping to make some myself.

Two hits in one day - first www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=527&page=1#Item_16 - and now this! Wonder what Paul in Montreal will say.

If not for the test results saying it works, I'd call it falacious - true the incoming air gets preheated by capturing escaping heat and returning it to the interior - but that air started much colder, so you end up no further ahead?

The Howarth windows have just two single panes, not 2G inner. Thinks - so secondary glazing in Listed Buildings not such a bad idea after all - do you suggest this to yr clients, Biff?
Dr. Mike McEvoy, The Martin Centre, Cambridge University, is behind DwellVent, Howarth's partner co. - Howarth emphasise you can't just fit the windows, it's a whole-building package, to make it work.

Posted By: biffvernonnegative U-value, i.e. they gain more heat than they lose

Indeed - the principle can be applied to whole walls, slight internal vacuum drawing air through the pores of the wall and bringing all the escaping heat back in with it.

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