View Single Post
Old 02-06-12, 04:44 PM   #18
Journeyman EcoRenovator
NeilBlanchard's Avatar
Join Date: Dec 2009
Location: Maynard, MA Eaarth
Posts: 383
Thanks: 78
Thanked 39 Times in 32 Posts

It is the trapped air that provides the insulation, and I've heard that the biggest space that works is about 5/8-3/4". Less than this provides less insulation, and more than this doesn't provide more insulation because the air starts to circulate because of the thermal flow.

So you can't just put double or triple layers of glass into the muntins that are designed for single panes. If you can fit 2 layers in, then great, but the air space is probably less than optimal.
NeilBlanchard is offline   Reply With Quote