Thanks all! I replaced the thermostat and the water got about 20 degrees warmer, but still not hot. It gets down into the 30's at night and only 65-70 during the day right now in Arizona, so I guess as soon as I start to use it, more real cold water is entering the water heater and cools it down pretty fast? I'll bet when the temp heats up, the water will be much warmer. It took about 25 minutes under load to hit 180.