I am finishing up my plan for renovating a 5-unit small apt building. It is electric-only and the previous owner had one electric hot water heater in the basement. To minimize it running cold he reduced the copper down to 3/8″ and then back out to 3/4 on the inlet side. So my tenants will probably complain about no hot water.
So if I add another HWH, should I parallel or series plumb it with the existing one?
remodeler
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Replies
If you series you don't have to worry about them 'sharing', but for high demand periods, there is an extra 15 minutes when the second one is just a tank and not heating -aka putting btus into the water.
In parallel, you get max elec input into the water right away, but if you do not balance the flow between the 2 WH, one will do most the heating. You almost need to put a flow meter on them in parallel and adjust with valves, as in zoned heating.