Kenneth wrote:

Next I plan to modify the box so I can let the filtered warm air into
the house during the winter.


I know that it is tempting, but there are significant health
risks. You would be loading the air with particles that
cannot be seen, but do lodge in your lungs.

There might be ways (heat exchangers) to capture the energy,
but breathing the warm vent air is not the way to go.


Nah, just quit clipping nostril hairs - unless you're THIS close to having
enough for a sweater.