Trekker Series Pellet Insert Performance You Can Feel The new Trekker pellet insert with Efficient Energy (E2) technology is the most powerful and efficient insert ever designed by Quadra-Fire. E2 technology helps achieve 83.2% efficiency—saving money by burning less fuel. The standard 7-day programmable thermostat, 52 lb hopper and easy-clean cast iron firepot ensure this pellet insert is easy to operate. And these efficient pellet-burning inserts are the only inserts available with cast iron construction on all major components—proving it’s built to last. Heat large spaces with up to 51,000 BTUs—heats up to 2,900 square feet, based on climate and home efficiency EPA certified, with low emission levels of .74 grams per hour Load less fuel with a 52lb hopper Use less fuel with 83.2% efficiency Exclusive "Efficient Energy" (E2) burn technology makes it easy to maintain your heat Cast iron heat exchanger, firepot and exterior add detail and durability 7-day programmable thermostat