The most insulative type of insulation for behind drywall is spray foam insulation, but this is the most expensive insulation available. The most common insulation—sometimes considered the best for the value you get for the money—is fiberglass roll or fiberglass batt insulation, which is significantly more affordable but also far less insulative. The best kind of insulation for your house will also vary based on the climate in your area, your budget, and more. A professional insulation company can help you decide which type is best for your home.

There are two reasons why cellulose insulation repels rodents (and insects). First, the insulation has been treated with boric acid, which is a natural pest-repellent. In addition, the loose-fill style of cellulose creates less-than-ideal conditions for mice and other rodents to nest and burrow, helping to keep them at bay.

If you have bubble wrap lying around the house and you don’t care about the odd look, taping bubble wrap over a window is a very affordable way to insulate it. Another inexpensive option for insulating windows is to add new caulk around the glass. This step quickly cuts down on air drafts for older windows, and a tube of caulk only costs a few dollars. Adding plastic shrink film around the glass is another cost-effective option. You can purchase a kit of plastic film for a few dollars per window.

Air sealing isn't necessary for attic insulation, but it's incredibly helpful since it can help you identify and patch any existing air leaks. Failing to find these leaks before adding insulation can render your insulation less effective, leading to higher energy bills and potentially costly repairs down the line.