In-situ measurements of residential energy performance using electric co-heating

An experimental technique is presented, called electric co-heating, for measuring the net efficiency of heating and cooling systems in residential buildings. In this technique, constant temperature is maintained inside the test building by thermostated, portable electric heaters. The net heat gain from any heating system in the building is measured by the reduction in electric heating needed to maintain constant indoor temperature. The method is illustrated with actual efficiency tests of a central gas fired heating system, an open fireplace, and a central air conditioner. Other capabilities of the electric co-heating technique illustrated here are the measurement of heat load caused by air infiltration and the measurement of an equivalent conductance of the building envelope. The in-situ characteristic of the method is stressed: actual, net heat gains, and cooling and heating loads are measured, reflecting the interaction between the tested appliance and the building containing it. In this context heating efficiency improvements of a heating system can be measured whether they stem from bettered combustion efficiency or from insulation of heating ducts.