An acronym for Solar Energy Factor, a method used to determine the efficiency of a solar water heater; in concrete terms, the energy delivered by the system divided by the electrical or gas energy put into the system.

Things you need to know

The higher the SEF, the more energy efficient the water heater. SEF ratings run from 1.0-11.

Also known as

Solar Energy Factor

Cost Considerations

Higher SEF systems are more expensive initially, so the money that you may save depends on several factors, i.e. how much hot water you use, the cost of conventional fuels in your area, available solar energy to be converted into solar power, etc.

Costs vary greatly by region (and even by zip code). To get free estimates from local contractors, please indicate yours.

Mentioned in

Solar Water Heater Installation Cost