Insulation is one of the most important elements of a home’s efficiency, helping to keep energy bills low and the interior comfortable.

Making sure that a home has at least the minimum recommended levels of insulation may be a job best suited for a professional contractor. Shop for estimates from several local contractors; then choose the one you think will do the best job.

If you choose to check your home’s insulation levels yourself, learn how to do the job properly. Keep these tips in mind when making a decision:

• You’re going to spend a lot of time in the attic, because this is the key part of the house to insulate. Most attics are tough to walk around in, require careful stepping to avoid falling between the roof trusses, and they can be hot and uncomfortable.

• You must wear protective clothing to avoid contact with the material. Long-sleeve shirts and long pants, gloves, safety glasses and hats are recommended, though you might also want to wear a cotton mask or even a dust respirator.

• You’ll be working around vents, recessed lights, stovepipes and electrical wires. All of these pose special considerations to ensure safety and ventilation in the attic.

• Remember that this is a job that has to be done just right to make it effective. You’re going to find places in the wall cavities, under floors and in the attic that are hard to reach. You can’t skip these places and hope that the insulation will be effective.

If you decide to do the work, you must learn where to look for insulation; find out the key areas that need the protection insulation offers your home.

The U.S. Department of Energy has published excellent materials on this subject, and you can find copies online at www.eere.energy.gov.

Among the key areas that need to be insulated to minimum recommended levels are:

• Unfinished attic spaces, where insulation is needed between and over the floor joists. Don’t forget the attic access door.

• Finished attic rooms need insulation between the studs of knee walls, between studs and rafters of exterior walls and the roof, above ceilings and into the joist space.

• Exterior walls are important, especially between the living spaces and unheated rooms like garages or storage areas.

• Floors above cold spaces need special attention as well. This includes floors above vented crawl spaces or unheated garages. Insulate slab floors built directly on the ground, along with any portion of a floor that is cantilevered beyond the exterior wall below it.

When you’re ready to do the work, be sure to protect yourself. If you suspect that vermiculite products have been used in your home, take special care. Check out the Web site epa.gov/asbestos for information on Environmental Protection Agency’s recent warning on this material and several Web pages with reports, fact sheets and other general information.

Keep in mind that insulation must have a continuous layer of material with no gaps, cracks or air bypasses to allow it to work effectively. This leads to some special care in installation. For example, insulation at the edge of the ceiling cannot be allowed to contact the roof decking and block airflow from the soffit vents. Batts or blankets should butt tightly against framing or other insulation. The material should be cut to fit at framing joints so that there is no buckling or gaps.

And special care must be taken when insulating near recessed light fixtures. Fire safety requires that you don’t cover standard recessed lights with insulation material.

A final note on installation: If you’re doing the job yourself, read the instructions on the package carefully and follow them.

Energy experts offer one more bit of advice before getting too far along in your insulation project. Check out your entire house to see what other energy-efficiency improvements you ought to make. Windows and doors that leak, for example, will help defeat the benefits of insulation by wasting excessive amounts of energy through air infiltration. Take care of many of the other problem areas in your home first to maximize the protection insulation offers the home.

If you get an energy audit of your home done first, you’ll know exactly where the problem areas are and what recommended repairs or improvements are needed.

Ken Sheinkopf is associate director for the Florida Solar Energy Center in Cocoa, Fla.