Any house that averages out to net zero energy consumption. A zero energy home produces as much energy over a year as it consumes, typically using photovoltaics, or combined heat and power (CHP) to generate electricity on site. In a zero energy home, efficiencies in the building enclosure and HVAC are great enough that electrical plug loads tend to dominate; therefore, these homes must have the added focus of high efficiency appliances and lighting. Several incompatible definitions are commonly used, including net-zero site energy, net-zero source energy, net-zero energy costs, and net-zero energy emissions. Therefore, terms should be clarified when this name is applied.