A central heating system provides warmth to the whole interior of a building or portion of a building from one point to multiple rooms. When combined with other systems in order to control the building climate, the whole system may be a HVAC heating, ventilation and air conditioning system. Central heating differs from local heating in that the heat generation occurs in one place, such as a furnace room in a house or a mechanical room in a large building though not necessarily at the "central" geometric point. The most common method of heat generation involves the combustion of fossil fuel in a furnace or boiler. The resultant heat then gets distributed: typically by forced-air through ductwork, by water circulating through pipes, or by steam fed through pipes. Increasingly, buildings utilize solar-powered heat sources, in which case the distribution system normally uses water circulation. In much of northern Europe and in urban portions of Russia, where people seldom require airconditioning in homes due to the temperate climate, most new housing comes with central heating installed.