The 1600EF outdoor furnace is a versatile unit. It is designed to either work as a standalone unit or in conjunction with your existing HVAC ductwork. With up to 180,000 BTU’s per hour, this unit is a convenient and economical way to heat a home up to 3,000 Sq. Ft. It ties into your existing duct work providing reliable and inexpensive heat all winter long. The 1600EF comes pre-wired with a 3-speed blower, designed to go at 1200, 1500, and 1800 CFM speeds, all of which is sealed in a weatherproof enclosure.