Water stoves, also known as outdoor wood-burning stoves and outdoor wood boilers (OWBs), are freestanding heating units used to heat homes and domestic hot water, hot tubs, swimming pools and greenhouses. Situated outside the building envelope, they typically consist of a water reservoir and firebox, appearing together like a small tool shed with a smokestack. Air is heated in the firebox and passed through channels in the water reservoir, which is heated and pumped underground through insulated pipes to the house. A thermostat that monitors the temperature of the water in the reservoir controls the furnace draft.

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