The Harman Magnafire SF-250 Coal Stove is our true heating workhorse, with a heating capacity to heat 3,000 square feet and an effective burn time of more than 24 hours. Featuring the exclusive Spiral Chamber System, the SF-250 achieves unrivaled efficiency by forcing gases to spiral around its heat exchanger before exiting the flue. An electric blower forces air throughout your home, resulting in 25 percent less heat loss through the flue pipe. An optional heat collector transfers superheated air to hard-to-heat areas or ties in with an existing hot air system. A stainless steel coil is available to heat domestic hot water, enabling the versatile and powerful SF-250 to meet all your heating needs.