We have a fairly new water heater - installed this summer when the old one started leaking. This one has never seemed to heat as hot as the old one, even though the dial's on the same setting. No problem, we can turn it up. HOWEVER, it seems to be heating inconsistently. One evening this past week it provided enough hot water for a shower, followed by a hot tub bath. Two days later, (and we hadn't run anything else needing hot water!), it provided barely enough hot water for a tub bath alone, and that was on full-blast hot (which I could hold my hand under comfortably). Later that same evening, I turned on the hot water and got water hot enough that I couldn't keep my hand under it. What gives here? Thanks for any and all help!