Taffy Turner
Established Member
Roger,
Funnily enough I was wondering exactly the same thing myself. Having given it some though whilst driving home last night (I haven't really got time to run more simulations), I would expect the relative difference to be greater with single glazed windows, as the initial heat flow will be much higher. (Single glazed windows have a U value in the range 3.3 to 3.5 normally).
There is another benefit, as my calcs for the double glazed units didn't take account of cold air infiltration, as most double glazed units are more or less airtight. This is definitely not the case in my experience for older single glazed windows, which can be draughty as hell! In this case, having close fitting shutters would help to prevent draughts.
Just for information, a cold draft in through a window is an effective heat loss, as the cold air has to be heated up to room temperature.
Regards
Gary
Funnily enough I was wondering exactly the same thing myself. Having given it some though whilst driving home last night (I haven't really got time to run more simulations), I would expect the relative difference to be greater with single glazed windows, as the initial heat flow will be much higher. (Single glazed windows have a U value in the range 3.3 to 3.5 normally).
There is another benefit, as my calcs for the double glazed units didn't take account of cold air infiltration, as most double glazed units are more or less airtight. This is definitely not the case in my experience for older single glazed windows, which can be draughty as hell! In this case, having close fitting shutters would help to prevent draughts.
Just for information, a cold draft in through a window is an effective heat loss, as the cold air has to be heated up to room temperature.
Regards
Gary
