Kozy Heat Chaska 25

It's sized for roughly 650–1,300 sq ft, depending on your layout and insulation. The manual rates it at 26,000 BTU/h maximum and 13,500 minimum on natural gas, and 25,500 maximum and 13,000 minimum on propane. The brochure lists its EnerGuide P.4 efficiency at 71.44% on natural gas and 72.08% on propane.

It needs an opening at least 17-5/8 inches high, 25-7/8 inches wide at the front, 20-5/8 inches wide at the back, and 15-1/4 inches deep. The fireplace has to be a wood-burning masonry or factory-built fireplace. Smoke shelves, shields, and baffles held on with fasteners can come out, and firebrick can be removed to reach the minimum, but cutting the existing fireplace's sheet metal isn't allowed.

It vents up the existing chimney through two 3-inch flexible liners—one for exhaust and one for outside combustion air—running to an approved cap at the top. Kozy Heat's #816 kit includes 36 feet of expandable 3-inch pipe and a round cap, and BDM, Amerivent, Metal Fab, Selkirk, Simpson Dura-Vent, and ICC systems are also approved. The chimney must be 10 to 35 feet tall, at least 7 inches inside (factory-built) or 6 x 8 inches (masonry), and it can't serve any other appliance.

Yes, the burner can still light and run on its backup battery pack, which takes four AA batteries (not included). The fan won't run on battery power, so the insert heats the room without the fan pushing the warm air out. The rest of the time it needs a 120-volt, 6-amp supply that's always on, with no switch on that circuit.

The included Proflame 2 remote turns the fire on and off, steps the flame through six levels, and runs the fan through six speeds. It can also act as a room thermostat, including a smart mode that turns the flame down as the room reaches your set temperature. You can switch the pilot between intermittent ignition and a continuous pilot, and the option list adds a Sit Proflame wall-mount transmitter.

Yes, but it's built for natural gas, so propane takes a certified conversion done by a qualified installer before the logs go in. The manual lists the propane conversion kit (LCK-CXS-S) as sold separately, and the option list includes a propane valve step motor. On propane it's rated at 25,500 BTU/h maximum and 13,000 minimum.

Plan on a screen front and a shroud—the brochure lists the screen front as required and says the shroud is required for installation. Fronts come in black rectangular, black prairie, or vintage bronze arched mission, and shrouds come in black at 22-1/2 x 36, 25 x 38, or 30 x 44 inches, or as a blank shroud. Black brick, Canyon Creek, traditional brick, or black glass firebox panels are optional, and the log set, fan, and remote come with the insert.

A 9-inch-deep combustible mantel can start 9 inches above the top of the insert, and it can get 1 inch deeper for every added inch of height. Combustible side walls need 3 inches of clearance, and the ceiling must be at least 55 inches above the fireplace enclosure floor. The manual doesn't give a separate rule for TVs, so plan any TV around those combustible clearances with your installer.

Yes to both. The manual says it may be installed in a bedroom, and in an aftermarket, permanently located manufactured home (USA only) or mobile home where local codes don't prohibit it. It still has to go into an existing wood-burning fireplace and chimney that meet the size requirements.