A solar collector is a device that captures solar heat and transfers it to heat water most commonly for sanitary hot water production, or in cases where a building has a very low heat demand, then often for both space heating and hot water. Larger scale active solar thermal technologies can also be used for cooling and steam production. Steam produced in this way can be used to drive turbines for electricity production.
Active solar heat technology produces heat for heating either water or air. Air heating solar collectors can be used to directly assist with space heating through the ventilation system of the dwelling. Solar air systems are of greater benefit in airtight houses with low energy demands. Water heating solar collectors are the most commonly encountered of the two.