The Iron Strike Montlake 230 wood insert is capable of up to 76,000 BTU/hour of heat, converting your existing masonry fireplace into an efficient wood heater for you and your loved ones to enjoy for years to come! Your Montlake 230 features Iron Strike's Thermal Fin Technology, a cast iron heat exchanger that keeps heat from escaping up the chimney. For further heat circulation, a standard 150 CFM blower is included.