Enjoy Clean Anthracite Heat! Leisure Line’s maximum in home heating, this unit has twin 90,000 BTU burners. Heat ranges from 5,000 – 180,000 BTUs can be expected with this unit. If you’re the person who wants the most from their heating dollar, then the Hyfire is the one for you. Hyfire stoves can be ducted directly to an existing hot air furnace, however the best central heating solution would be one of our efficient, clean Anthracite Burning Hot Air Furnaces.