Wish we would have thought of it several years ago, but now I’m not so sure we will live here long enough to make it worth the cost. Aren’t those pumps really expensive?
To back this up, we opted for the best Andersen windows and doors, blown cellulose in 2 X 6 exterior walls and about R-70 blown cellulose in the ceiling.
I caulked all the receptacle and switch boxes and foamed every hole where wiring was run through 2 X 4s and 2 X 6s, sealing off each column from the next.
We have broad roof overhangs to keep the sun out, except in winter months (our architect placed the house to take advantage of winter sun and avoid summer sun.) Summers in the Ozarks can be brutal.
One home heating expert recommends sealing off the attic vents but I'm not sure this is a good idea.
The University of Minnesota had a Cold Climate Housing study some years ago. You might see if you can find a copy. It's useful no matter what climate you have.