Hey everyone -
I have a question on multiple HWHs installed in my residence. When I bought the house it had two 40 gallon electric HWHs plumbed in series. It's a large house, and we have two teenage kids and relatives that visit for long periods. We have always enjoyed the voluminous amounts of hot water.
The HWHs were Rheem, with S/Ns of 1191****** (the house was built in 1992, so that makes sense). In 2000, I did some remodeling and at that time attempted to check/replace the anodes, dip tubes, etc., but was unable to break them open. This summer, the second HWH in the series failed with rusty water leaking out the top electrode. I simply removed it from the circuit, and have been relying on the first heater. This setup seems to be working fine (provided, of course, that I get to the shower every morning before my daughter).
During the recent winter storm we had an extended power outage, and I decided I want to put a second HWH back in the circuit. I plan to wire the second HWH to my garage electrical subpanel where my generator transfer switch is located so I can have at least some hot water during the next extended power outage. I am considering the GE 9-year electric 50 gallon from HD as it seems the best value for what you get. I would then replace the first HWH in the series within a year or so, as the budget allows, with a similar one under the assumption that it will probably fail soon as well.
Before I jump into this, I have a few questions:
1. Is it better to plumb two tanks in series rather than get one larger tank? It seems an 80 gallon tank costs more than two 40s or 50s.
2. Is plumbing them in series (vs parallel) the right way to go?
3. Is it OK to have two HWHs of different sizes (40+50) plumbed in series?
4. Am I correct in wiring the second one to the generator transfer switch so that if I lose power and am running off backup power I don't have to run through 40 gallons of cold water before I get hot water?
5. We have propane F/A furnaces, one of which is next to the HWHs. Should I consider propane for the second HWH? This would be nice in a power loss situation, but I have not had very good luck with propane HWHs in the past. And I have had to replace the propane valves on the furnaces, fireplaces, etc. on a fairly frequent basis around here. And I haven't heard too good of stories about the new gas HWH FVIR thingamajigs.
6. Are there other considerations I should consider?
Thanks all for your input.