I've had two red dot fan heaters, about 10,000 BTU each, about four years. They have worked well...no problems My boat neighbor used two also. They are VERY NOISY. (Noiser than an automobile). I also used Webasto provided fan heaters, about 5,000 BTU use what appear to be computer type fans and are quiet...but audible. They cost the same (about $200) as the red dot, so you'll need twice as many. (It's never easy, is it?) My neighbor had one Webasto fan die over the same four year period. I also bought an auto heater radiator and added a room type air fan, metal cage, about $60 total, with approx 5,000 BTU output...Works fine but is noiser than the Webasto, less than the red dot. Baseboard (passive, home type) fin heaters, if you have the space, are best...no noise, no current draw, but finding space on a boat is tough. I used them in the engine room. They also radiate heat after heat shut down due to added volume. Home Depot sells them as short as three feet long, but you can cut longer lengths to size when necessary. Webasto fan heaters and baseboard fins use 3/4" hose, red dot uses 5/8" hose connections. When installing a system, use enough fan heaters and baseboard to match the heater output capacity less 10% to 15% or so...then you can add a fan heater here and there after you run it and experience actual heating. On my 40,000 BTU Webasto (output) I have fans/baseboard rated at 50,000 BTU...unit still reaches max water temp so main burner cycles on and off in cold weather. Rob Brueckner Hatteras Yachtfish