Insulation isn't new. The pioneers stuffed walls with everything from straw to corn husks.

According to Home Products Guide magazine, what is new is the amount experts recommend for keeping a home comfortable in all seasons.The insulation homeowners choose depends on the R-value needed and the space to be insulated. R-values represent the ability of a material to resist heat flow. The higher the R-value, the better its resistance.

The U.S. Department of Energy (DOE) recently upgraded insulation recommendations. (They were last changed in 1975.)

"The new recommendations take into account the increased cost of heating and cooling homes over the past several years. Insulation is relatively inexpensive," says Dr. Dave McElroy of Oak Ridge National Laboratory, which helped develop the recommendations. "This cost-benefit ratio makes increased insulation levels worthwhile."

The DOE increased its minimum R-value recommendations. They are now specific to zip code areas and take into account climate, heating and cooling needs, forms of heating used and energy prices.

According to Sen. Timothy Wirth of Colorado, chairman of the Alliance to Save Energy and member of the Senate Energy Committee, Americans spend a hundred billion dollars on household energy, or more than $1,100 per household annually. The DOE estimates 50 to 70 percent of the energy used in the average American home is for heating and cooling. Yet, most of the housing stock in the United States is not insulated to recommended levels.

In an attic insulation study done by National Family Opinion, an independent research firm, it was found the average insulation level in attics is about R-20. But the DOE now recommends an average of R-40.

According to Wirth, field tests show wall insulation is one of the most effective energy savers. Average heating and cooling costs were reduced 24 percent by this measure.