My wife and I are in the early stages of remodeling a 120 year old, 3,500 square foot East Lake in Grand Rapids Michigan. However one of the first things that we are looking at doing is making the house air tight to help retain the heat. This will be our third winter in this house and air leakage is so bad, we can't keep it warm enough without shutting down 1/2 the house in the winter. Most of it is because of air leakage around windows, doors, and just about everywhere.

In the long run, we are going to work our way to net zero, but a friend suggested that we seal the air envelope before we do much of anything else. What tips do you have regarding tightening the house up and preventing air leaks.

We would like to get it tight enough that we can install a fan in our attic window and have close to the same volume of air coming in an open basement window.