I've got a Buck insert in our downstairs fireplace. Cranks out a ton of heat. A few years ago I added an external blower and ducting to bring heat upstairs. Huge difference. Used to be mostly just the upstairs floors that were warm, but we got it to where we could overheat the house in the coldest weather.
Had central HVAC installed a couple of years ago and haven't used the buck stove since except for during a long-term power outage and then I only used it a couple of days until I got a generator. Ran the buck stove blowers and a few lights off an inverter I had connected to my truck, which just stayed outside idling the whole time.