This second WH was bought about 13 years ago.
Now that it is open I see that: THERE IS NO SACRIFICIAL ANODE. This accounts for why I couldn't figure out a few years ago how to remove and replace it. I thought EVERY electric water heater had a sacrificial anode to combat electrolytic destruction of the metal case, so as to prolong the life of the case, by postponing leakage. WHAT GIVES? This is especially displeasing since I have another Sears WH to install later today or tomorrow. SHOULDN'T EVERY GOOD ELECTRIC WATER HEATER HAVE A SACRIFICIAL ANODE?
The cold water input tube is made of plastic. It reaches almost to the bottom of the tank and then curves around in a 270 degree arc. This I'm sure makes the water swirl around when cold water enters the tank and is the reason they advertise turbo-swirl action. (Which I think they somewhere explain keeps the sediment from forming a mountain, but rather a mesa. :) I think they are more tactful than I am here)
There is NO hot water output tube, and no evidence so far that there ever was one. The water rises to the very top of the tank, and leaves through the pipe that comes out of the top.
The glass lining is not very apparent. Before cutting it open, both a friend and I stuck our fingers in the hole for the heating element and felt the inside. It felt like metal, making us wonder where the glass was. Now that it is open, about 95% of the inside seems to have a set of black streaks on brown, like some sort of cheetah skin or some wild cat. It feels like metal. On closer inspection, 5% of the surface, especially part of the "ceiling", the top, seems to be plain light brown and smooth, and feels like a cross between glass and a plastic surface. And the patterned area rubs off after a few rubs with my finger, showing the plain light brown underneath. So the light brown must be the glass and the streaks must be deposits from the water. The glass shows no sign of breaking, even next to where I sawed around the circumferance. Although I haven't yet reached the bottom of the tank.
Both the lower element and the drain are about 7 inches** from the floor (or in my case, the pan the WH sat in.) OTOH, the water still in the bottom of the WH is 1 1/2" deep, even though the drain valve was 7 inches above the floor. That must be because when I tip the WH in one particular direction, water leaks out though the same hole that made me get a new water heater. (I think there was a leak, but I can't quite remember now. It's been 8 months.)
**For the new water heater, bought 8 months ago, the drain valve has been moved to below the bottom heating element. It's now only 4 inches high instead of 7. I don't know if this is good or bad. It seems to mean that one can drain the sediment BEFORE it is as high as the heating element. Why did they make it the same height in the first place? (But I'm not going to do any sediment draining.)
**The valve on the new one also doesn't point straight down, more like "Southeast", if Up were north. I thought this was an assembly error, but maybe it was to make it easier to attach and route a garden hose???????
In the bottom middle of the water is a 3" circle of sediment. I have to cut another big section from the sides to reach this part, but the sediment seems no more than a half-inch, maybe 3/4 inches deep. As such, after at least 12 years, it was more than 5 inches from fouling the lower heating element. Bearing in mind that the tank is only 3 inches wide at the half inch deep mark, but 16" wide at the 4? inch deep mark, or in area the ratio of 9 to 256 I guess with my water, which is city water almost entirely from reservoirs and is neither hard nor soft, the sediment would not have reached the heating element for 300 years.
The water heater never had the sediment drained out. It never had the valve at the bottom opened until I tried to drain the tank prior to replacing it.
The WH is 21 1/2 inches in diameter, but that is at the top which is a little bigger than the middle because there is a rim around the top (and the bottom). When the outer metal shell is cut off, and the stiff foam is removed, the water heater is 16" in diameter.
The foam is covered underneath and above with a continuous sheet of clear vinyl. It's 2 1/2 inches thick all around Except about 6 inches where the heating elements and thermostats go, where it is filled top to bottom with a soft fiberglass batt.
Also, the top and bottom of the water chamber are semi-spherical. The top lid is put on so there is at most 1" of foam the top most point of the sphere. Maybe less. I haven't gotten those parts apart yet. I'm sure the bottom is also less than 2 1/2" but I don't even have an estimate of that yet.
*** Its arrangement of parts, its owners manual, and its component parts (heating elements and thermostats) was almost identical to the house's original water heater that it replaced. That one was made by A.O.Smith and was 65 gallons (for a 3-bedroom moderate-sized townhouse.) In fact that is why I bought my WH from Sears. A.O.Smith doesn't seem to sell one at a time, and Sears's was the only one I could find which had the hot and cold water pipes at the same distance from each other as the previous WH. (So I'm compulsive. Sue me.)