I did this 6 years ago. Comes to find out my house had ZERO insulation in the walls. They did $3500 worth of work for like $650. I was busy when they initially sent me the contract for the work which was originally like $900 or so and completely forgot about it. Then I got an email in December saying if I signed the contract before the 5th or something they'd take $300 off. Definitely worth having them come out.