I took some pics of my current water heater.
This is the current unit. It is in a little closet that has its own door. This is out in the garage.
Obviously a 40 gallon tank. 35.5K BTU and we keep the temp on about 1/3 of the scale. It could get a LOT hotter. We don't run out of hot water.
Now to find a local source for a AO Smith water heater. So far they all want to sell only to a plumber.