The feasibility of applying combined heat and power rationale to domestic buildings connected to mains electricity and gas grids is assessed. The characteristics of electrical and thermal demands occurring within UK dwellings are reviewed. A micro-CHP system of 1-5 kW(e) capacity is proposed and its control and operation described. It is considered that the widespread application of such systems within the domestic sector could yield enormous benefits with respect to reducing annual rates of CO2 emission and primary-energy consumption.