I know this has been asked before. My problem is when I have family visiting for a weekend I run out of hot water pretty quick. I am limited as far as space goes. I was told I can hook two water heaters together to increase the amount of hot water. My plan of action is to bring my cold water into the first water heater and take the hot outlet into the cold side of the second heater, Then connect the hot outlet of the second heater to the hot water line of the house. There is a switch that can disable the first water heater therefore when I have no visiters I can turn it ( the first heater) off therefore it would serve as a storage tank. The second water heater would supply hot water for the house all the time. Will this work?

I would not pipe in series but parallel.