#28986
Sir Humphrey
Strataguru

    @Boronia said:
    A quite popular window “treatment” in Sydney, in units with large glass areas, is aluminium foil. It would probably be much more noticeable from outside than bubble wrap. And probably more effective as a heat barrier.  

    Foil against the glass would be effective for radiant heat, such as when sun shines directly in through a window. Foil does not do much for insulation without an air gap.

    Bubble wrap is good for insulation against conducted heat, either to keep heat in in winter or to keep it out in summer. 

    Glass is quite a good conductor of heat so if the air is 20 degrees warmer on one side than the other of a sheet of glass that might be as little as 3mm thick, you will get a lot of heat move across. The pockets of trapped air in bubble wrap act like the narrow slab of trapped air between double glazing, and that air is a much poorer conductor of heat than the glass.