Additional Glass Panel

[Howard]

We have vinyl windows that are double paned low e glass and seal reasonably tight. They also have a channel on the outside for screens, which we remove in winter.

We have plenty of windows and during the day our south facing rooms are very comfortable.

In the evenings or on cloudy days we have some heat loss.

Anyone have any experience with using a glass storm pane instead of the screens to further reduce heat loss?

Any suggestions for a source of aluminum or vinyl strips to make the storm glass?

The window manufacturer does NOT offer any storm glass.

Thanks for inout

[John Gilmer]

We have similar windows.

What you seem to want is a version of the old fashion "storm windows" that fit over your single layer glazing window.

These were routinely vented at the bottom. They were a little better than nothing but not nearly as good as even bottom on the line double glazed seal windows. I suppose they might reduce heat loss on a windy night a little but to keep them from acting as a vapor barrier they have to be vented to the cold air and this limits their effectiveness.

[nicksanspam]

Why not? Warm air rises.

Nick

[tgdenning]

They don't have to be vented if the 'actual' windows are sealed well, since there would be very little water vapor. Old storms that I've had just have 'weep holes'.

On the other hand, the efficacy in reducing heat loss will depend on the spacing between the third layer of glass and the actual windows. It isn't likely that you can get the new glass close enough to create a useful insulating layer of air. Anything over about 3/4" space will be useless due to convection within the space.

-tg