Call your utility company and ask for an energy audit. The minimum R-value for insulating your home depends upon the area where you live, how your house is built and the heating source you use.
Research over the Internet and find out what climate your home is in by going to the Department of Energy's Web site at: www.energy.gov. If live in a mild climate you need R-11 insulation in the walls and floors and R-19 in ceilings. If you are in a moderate climate, you should have R-19 in the walls and floors and R-30 in ceilings. If you live in a cold climate you should have R-19 in walls and under your floors and R-38--R-49 in ceilings.
Consider various forms of insulation for different spaces in your house. For overhead spaces consider fiberglass blankets, batts, spray foam insulation, insulated board products or reflective insulation systems. You can fill enclosed cavities behind finished walls with blown-in insulation with a hopper or a spray foam insulation.
Combine insulation types of insulation. You can roll insulation over of loose-fill insulation in an attic; or do just the opposite. If your attic temperature falls below 0°F, cover a low-density, loose-fill insulation with a blanket insulation.
Install batts of fiberglass insulation that have vapor-retardent facings if you live in an area that is damp and humid. Or use insulation batts with flame-resistant facings for unfinished areaa like basements, where the insulation will be exposed.