Insulated storm door snake oil question
I’m looking at fullview (interchangeable glass/screen panel) storm doors. I see that I can order a regular aluminum one (which I presume has some sort of weatherstripping), or this one for twice as much:
Description of Product:
6.3 R Value equals over 7 x the insulating value of 1″ wood core doors! Polypropylene weatherstrip and interlocking glass sashes keep the weather out
First, isn’t this R-value pretty unlikely?
Second, I’m curious how the total R-value, of the storm door and the exterior door inside the storm together, would be figured. Especially considering the airspace between, they’re not additive, right? If I’ll see no benefit other than rain coverage and some slowdown in air infiltration, I’ll get the cheaper one.
Professional/scientific opinions?
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Replies
To say nothing of the miraculous development of glass technology that a .2 U possible! I was just looking at a triple-pane krypton filled window that advertises at R-5. This door is the work of a genius!
I know it. Why have I been agonizing over those Canadian window prices?
Nevertheless, I still do wonder about the specifics of storm door help with the air infiltration problem. Factual? Purely anecdotal and baseless, if the regular exterior door is insulated and weatherstripped?
Is it a single or dual pane window. Single pane is about an r1. You see a lot of double pane windows that are between an r3 and 4. I just dont see a storm door have that kind of R Value.
they are 'fudging a bit' when they talk about the r-value of the door as 6.5. technically the door part is 6.5 as it is filled with and inch of foam, but the window unit in the middle obviously - not to mention the frame - reduces the whole unit r-value
i'm sure they make a solid door and the fine print somewhere alludes to the fact they are talking about it in general and other options reduce the actual r-value
i've never seen any test of full door area r-value with a door, screen door, framing and all mounted. it would vary so much depending on what you used that i don't see any reason to test it unless a manufacturer was trying to push a whole package
Minneapolis,
When comparing the thermal performance of doors, always refer to NFRC labels. The NRFC rating system calculates a door's U-factor by taking into account the entire door, including glazing panels and frame.
Needless to say, an R-value of R-6.3 (U-0.159) is unlikely for a storm door.