::I don't know, if all you need is to make air dry, then dry it; fresh ::air is needed anyway. Normally built uninsulated house does not ::provide enough fresh air, some incoming fresh air is needed. Double ::and tripple glazing takes sunlight making the house colder and even ::more humid. n summer. Ventilation is a different topic altogether. Air does need to be exchanged= =20 and double or triple glazing a property doesn't prevent this occurring. In winter much internal heat leaks out of a dwelling, often through the=20 roof (note houses that have no a little snow on a roof compared to those=20 whose roof is about to collapse with a few tons of snow peppering them),=20 roof insulation helps to prevent that, windows and doors also leak air=20 causing cold drafts. The nice hot air in the house will leak out of these=20 helping to mix cold clammy air with the nice dry(ish) warm air in the house= =20 creating condensation (if the internal air is at growing tomato=20 temperatures). Double and triple glazing of windows and doors prevents the= =20 leakage and in conjunction with insulation means that you don't need to=20 have the heating on so high or perhaps as much as you now only need to=20 maintain the status quo (reasonable group) rather than trying to replace=20 the leaking heat. This also means you can control how and where the air=20 exchange takes place. These days, the glass in double glazing can be specially tempered and often= =20 an inert gas is now used to help keep cold air out during winter and=20 preventing hot air getting in along with preventing infra red radiation. It works very well in the Scandinavian countries and Germany (where it is=20 most popular). My remarks about NZ stem from my stay there where two houses I stayed in=20 were freezing during the night (built around mid to late 90's) and this was= =20 in December. Here in Australia in Queensland insulation has only recently= =20 been considered for the roofspace, there are only a couple of companies who= =20 provide what I would consider proper wall insulation, mainly because people= =20 generally equate insulation with keeping out the cold not keeping out the=20 heat. Even new houses only have a thin plastic covered insulation sheet=20 applied which normally end up with holes in it as the water and electrical= =20 services are poked through. Colin -- cdb, colin@btech-online.co.uk on 5/02/2012 =20 Web presence: www.btech-online.co.uk =20 =20 Hosted by: www.justhost.com.au =20 =20 This email is to be considered private if addressed to a named individual= =20 or Personnel Department, and public if addressed to a blog, forum or news= =20 article. =20 =20 =20 --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .