I purchaed one for $485 this summer from Creative Energy Technologies. I like it but only with a little hesitation. First, it takes a bit longer for hot water to reach your faucet. For instance, it may be a minute after you turno on your tub faucet to get water hot enough in which to bathe. Second, the pilot light has gone out on me twice. These are my only two complaints. I haven't really been able to compare heating bills but I am sure I will come out slightly ahead. The upside is, of course, unlimited hot water which can't be beat for long showers, a hot tub, or filling a tub. A 40 gallon tank just doesn't match up. Good luck.