U.S. Department of Energy Energy Efficiency & Renewable Energy U.S. Department of Energy Energy Efficiency & Renewable Energy


Use the glossary to access terms and definitions related to residential energy efficiency programs. Click the letters below to find your terms. Letters that do not appear currently do not have glossary terms related to them.

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Deemed Savings

Estimated energy savings from specific measures (e.g., insulation, duct sealing, etc.) based on historical evaluations of actual savings from measure installation. They are generally only calculated for measures with well–known and consistent performance characteristics. Deemed savings estimates can be derived from a number of sources, including past program evaluations, engineering estimates, and extrapolated results from other programs.


Demand is defined as the time rate of energy flow. It is the requirement for energy consumption of energy source(s) by an energy using system at a given instant or averaged over any designated interval of time. Demand usually refers to the amount of electric energy used by a customer or piece of equipment at a specific time, expressed in kilowatts (kW equals kWh/h) but can also refer to natural gas use at a point in time, usually as Btu/hr, kBtu/hr, therms/day, or cubic feet per day (ccf/day).


An improvement measure installed as part of an energy efficiency program strategy involving the direct installation of measures in customer premises, by a contractor hired by the program at no cost to the customer.  This measure is typically restricted to a specific set of pre-qualified eligible measures and may be subject to caps or other restrictions that related to the program’s cost-effectiveness guidelines or other criteria.

Discount Rate

The interest rate used to adjust a future cash flow to its present value. The discount rate can be in either real or nominal terms.