I'm installing a Garn 2000. Home is forced air and all electric. I'm heating 8000sqft - half of that is a full basement. The house has two 50-gallon DHW tanks. Both tanks are nearly 17 years old, so the life span is going to be short. So, here is the question: Does anyone have a recommendation for a DHW tank with smooth surface large diameter coil with electric back up? Doesn't matter to me if I go with two 50-gallon or even one 80-gallon. I just want a tank with a built in coil that merges well with my new system. Here's my rationale for going with the built in coil vs the sidearm exchanger. For the price I'll pay for all the fittings, sidearm, etc., and knowing that I'll need to replace the tanks in a few years, I might as well as go with new tank(s) with built in coil. The electric back-up is a must. Can anyone point me in the direction of the best brands to consider?