I’m in the market for a storm door with a replaceable glass panel for my front entry. The door faces south and gets direct sunlight for a few hours a day in the winter, but is shaded in summer. My options for glass are a single pane of tempered glass, a double-glazed panel of tempered glass, or a single pane of low-e glass. I’m leaning toward the double-glazed or low-e options, but I don’t know what the relative advantages of those two options are. I’d like to avoid a situation in which the space between the main door and the storm door acts like a greenhouse and gets crazy hot (my brother in law’s house has this problem, although his door gets more sun).
So, why would I choose double glazed over low-e or vice versa? Double glazed with low-e glass is not an option.
First of all, if it is in a door all of the options are going to be tempered glass by building code. Screen doors, sliding glass doors, and even windows near a stairwell or door where someone might push their hand through or fall against are going to be tempered.
Double glazed glass is also known as an insulated unit of glass, two panes with space in between usually filled with argon gas.These are the types of panes in most modern window applications. And most insulated glass now comes with Low-E on one of the panes. It stands for ‘low emissivity.’ This is a thin metalic coating placed on the glass to reflect UV an IV rays either back out or let them in and keep them from radiating back outside.
As far as I can tell from your post, your options are a single pane of tempered glass, a single pane of tempered glass with Low-e, and a double pane insulated unit of tempered glass without Low-e.
It seems very odd that you cannot get a double pane insulated unit with Low-e on one pane, which would be your ideal solution. This is the way most insulated units are made now.
I agree that it’s odd that there isn’t a low-e double glazed option, but that’s what I have available locally. I can get standard single pane, double glazed with “dual pane standard clear tempered glass” or “single pane low-e glass with hard coating” with the coating on the inner surface of the glass. These are from different manufacturers, btw, and confirmed with customer service reps for both companies.
So - ignoring the issue of a low-e coating that is exposed to potential scratches or other abuse - why would I prefer low-e over double glazed? And is either one really worth the price premium over single pane glass for a storm door as opposed to a regular window?