permaculture

[venaurafarm <venaurafarm@bellsouth.net>]

On 1/18/2013 11:03 PM, Scott Pittman wrote:
> I have always read that any airspace between the glass or poly should never
> exceed 5/8 of an inch to prevent a thermal loop from developing which would

There is plenty of glass double pane panels that have 3/4" airspace.

> defeat the purpose of double glazing.  This is certainly the rule in
> manufactured thermal pane windows and doors.  By evacuating the air space
> between the glazing panels you can slow down this effect with over time the
> vacuum gets lost.

My method just uses two Polycarbonate glazing attached to framing 
members, not air evacuated. My untested theory on prevention of thermal 
loops would be to use more framing members, blocking more light of 
course but creating a stronger panel that is more energy efficient. I 
would not hesitate to use this method on a skylight, in a sunspace or 
or a greenhouse. This by far the cheapest way to go plus extremely 
durable and lightweight; you get plenty of light with some degree of 
thermal efficiency.

LL