There are a lot of factors to consider when you are computing for the cost of weatherization in Johnston. Some of these factors include the size of the house, the amount of work needed, materials, and labor cost. There is really no definite way to get an exact estimate of the costs unless inspection has been made and all the problems are already found. It is highly advisable to get a home energy audit first before weatherizing your home. A professional inspector will be able to determine weak points in your home that will need attention and upgrade. An energy auditor usually charges $120 to $170 per hour depending on the size of the home. After this, you can start planning to upgrade and fix the problems.