[snip]


any other suggestions?


Build a frame around a fan to tightly seal into a window or door opening.
On a cold morning set this up and turn it on to depressurize the house and
then go from room to room feeling for cold air being pulled in to find all
the air leaks. I found some pretty substantial leaks this way. Nice of
the previous owner of my house to leave an old squirrel cage blower behind.

Steve.