I looked at instant water heaters but they are so expensive, like 4 times the cost of my water heater. Also I looked at the heaters that go with jacuzzis but they only maintain the temperature and don't heat incoming water. They too cost more than a typical LP Gas water heater.
I would rather just install another water heater next to the one I have. I saw some articles on here some time ago about installing these in series and parallel, somebody said parallel was best with water lines the same length.
What's the whole story on doing this?