By Heather Burlingame, Senior Production Editor | September 28, 2010

AllmandThree indirect-oil-fired heaters have BTU ratings from 320,000 to 505,000 and operate on 120-volt power. The burner has a 0.25-hp motor that delivers airflow between 2,500 and 3,100 cfm at a discharge temperature of 200 to 220F at a 50F ambient-air temperature. A heat exchanger serves as a barrier to the flame and allows fumes and combustion products to be vented while fresh, heated air is piped into interior spaces.