At least one energy expert thinks there should be an EPA-type rating for each house sold, just as there is for each car.

While this view has not yet gained much credence, there are indications that it may in the future, just as the idea of warranty programs caught on. The Department of Housing and Urban Development this year commissioned a manual instructing purchasers how to judge whether the insulation is good or insufficient, for example.

Utilities are now required by law to offer to perform energy audits for customers. FHA and VA lenders take utilities costs into account when determining eligibility for mortgages.

The Federal Home Loan Mortgage Corp., a government-chartered corporation that buys mortgages, recently issued its first guidelines defining what is considers an energy-efficient property. Financial institutions making loans to home buyers are not required to use these underwriting guidelines, but many do as a matter of practice if they intend to sell their loans to the mortgage corporation.

Items listed as contributing to the energy efficiency of a property include adequate insulation, double- or triple-paned windows, window shading for sun control, automatic set-back thermostat, solar heating and cooling, wood fireplaces, and earth sheltering.

Underwriters seeking to determine the eligibility of buyers according to mortgage corporation guidelines are advised that they can fford to spend between 25 and 28 percent of their monthly incomes for mortgage payments, insurance and taxes.