The horizontal power vented PTP unit heater line delivers up to 83% thermal efficiency in a small business-friendly package. The blower model BTP allows customers to add ductwork onto the unit to distribute heat and air better. This unit is an excellent fit for greenhouse applications and other situations that need better and more flexible air movement. Also, it offers up to 83% thermal efficiency. The aluminized heat exchanger is standard on all units, extending the life of your investment. Optional stainless steel heat exchanger Bent tube, low-profile design Enclosed fan motors and all controls are mounted inside the cabinet for protection from airborne moisture and dust 10-year heat exchanger warranty, even in greenhouse applications Quick and easy installations with wiring terminals and knockouts for quick access to gas and electricity and a roomy controls cabinet for ease of work Standard power exhaust simplifies side-wall or roof venting with a small diameter vent pipe Permanently-lubricated motor for trouble-free dependability Designed, Engineered & Assembled in the USA