Space heating/cooling, along with water heating, are the overwhelming majority of household energy use. In fact, in a heating-dominated climate there isn't much

Space heating/cooling, along with water heating, are the overwhelming majority of household energy use. In fact, in a heating-dominated climate there isn't much of win from having efficient lights and appliances, because the space-heating system has to make up for the energy not wasted by the lights/appliances. So it's unusual ("unique" is a high bar) in that it's one of the largest privately-owned energy-consuming devices where existing technology can result in substantial energy savings and emission reductions.