I had a Eberspacher heater that had not worked for years. To replace it, it would have been ~ $1600. This was ~ $160. It fit perfectly where the Eberspacher was. I didn't have to do much of anything wiring-wise or changing the exhaust but just hook it up. The heat is adequate for my 33' Nauticat.I've only used it about 10 times the last two years. It had cut out a few times, but seems to keep going once it gets hot. The controls are very basic. The controller cracked the 1st year when I dropped it, but it keeps working.It likely would not put out enough heat in extream cold weather, but for the Portland, OR area, it seems adequate.