On Sunday, February 19, 2017 at 12:37:11 PM UTC-5, wrote:
DerbyDad03 wrote: " all the time? I think not. While
the mail flap is less "leaky" than an open window, it's still an
opening that reduces the R value of the door.

BTW if simply opening your attic stairs causes heat to "blast" into
the attic, you may need to improve the insulation for the opening. "


My attic stair swings UP toward the
opening,

Color me confused. Attic stairs "swing" two ways.

They typically swing down (away from the opening) to open and up (towards
the opening) to close.

Unless I'm missing something, telling me that yours "swings UP toward the
opening" doesn't sound like anything out of the ordinary, assuming that you
mean "when closing".


and is closed-foam weather
stripped by me. Plus I have 1/2"
styrafoam on the top side of the panel,
beneath the steps, shiny side down.

My stairs are mounted to 1 x 4 slats which are mounted to the panel. Covering
the entire panel with foam would be impossible. The 1 x 4 slats have a much
lower R-value than the foam used for the box, so all of that area is basically
not insulated.

The box above the stairs fully insulates the entire opening with 1" of foam.
I highly recommend it.



A lot tighter than you might think. We
might add the foam dome you mentioned.
Thanks for mentioning it.