Q: I have a 40-year-old house which has insulation that now needs replacing. I would like to do it myself, and I’m thinking about buying batts of insulation that you can roll out. I want to know more ...

The right insulation will keep your home comfy and your energy costs low. Here’s how to calculate how much you need and what kind to buy. Adding insulation can be a low-cost way to cut energy bills.