The tank I installed:
This video is about how to install a small electric water heater. I did however err and should not have used PEX pipe right at the connection to the tank. It should be 18″ from the connection. So when you hook up yours, use copper pipe within the first 18″ of the tank. This is the Ariston GL4 S. It has a 4 gallon tank that is heated electrically with an element. It does have the standard anode rod that regular water heaters have so there is some maintenance required but the frequency of changing the rod depends on the condition of water in your area. The SharkBite fittings are a bit more expensive but they attach so fast and are quickly removable.