Attic ventilation is important to control moisture and keep cooling costs down. Heat can build up in the attic during summer months, and increase costs to cool your home. When it is in the 90s outside, the temperature in your attic can top 150 degrees.
Moisture in your home can rise into the attic. The moisture can collect and damage insulation and your home itself. Mold spores grow in wet areas, causing indoor air quality problems. Insulating and air sealing your attic will keep your attic dry and reduce energy bills.
Use loose-fill insulation, which is cheaper than batt insulation. Next seal all air leaks between the attic and your home. Don't cover soffit vents with insulation, because they allow for attic ventilation. If there already is insulation on the attic floor, check to make sure the vents are not blocked.