My Enviro Windsor is rated to heat about 1800 sq ft. Now that colder weather has set in, I am finding the need to turn it up a bit. It belches heat like a champ, but it makes me a little nervous running it at medium high for days on end, shutting down only to clean out every couple days. Are these stoves designed to run on the higher end of the heat range for extended periods? Am I expecting too much from it, I know that it is really a space heater, not a furnace?