Reduce Door Air Pressure Without Compromising Air Sealing

Not sure the ideal place or post this
​​​​​8x8x8 wellhouse with a 12/12 roof. There is a ceiling.
I'd like to insulate it better.

The problem is that it has an outswing door that is very tough to close due to the air pressure.

​​​​​​Right now, the ceiling is out (for a well pump replacement) so the cutout in the roof is exposed and the door shuts great.

The cutout will get a slantback vent but the ceiling will be reinstalled with r30 insulation on top and I am planning to sandwich some xps between the plywood ceiling and rafters that I can air seal.

The ceiling will have a sealed access hole beneath the slantback (for future well replacement).

What are my options for allowing air to escape when shutting the door but still be air sealed after?
Backdraft damper installed in the access hole door? Would closing a door be enough to lift the flaps?

 

Air pressure is likely NOT your problem. Besides, how often do you go into the pump house that door closing is a big issue.

For best results minimize the space you are insulating. The warmth to prevent freezing will come from the ground and the water passing through the piping. That is plenty if a very small (just big enough) well insulated cover is installed over the well head and exposed piping. Trying to keep a large room with a high ceiling from freezing is much harder.