British Energy Efficiency Federation was created in 1996.

Is it's Energy Efficiency.

rising energy costs had caused builders to increase the efficiency of their products with better windows and doors, insulation, and heating and cooling equipment.

If it is burned - which is the way such fuels are usually used - the energy efficiency is the energy efficiency of a heat engine. The theoretical maximum efficiency is the Carnot efficiency; the real efficiency will usually be considerably less than that.

Apartments.com and Rent.com both offer the ability to search for rental housing with energy efficient appliances. Both of these sites are free to use.