vitullostudio
New Member
Does it make any sense to boost the incoming water temperature into a natural gas tankless water heater by installing an electric tankless heater in series in front of the gas WH? It would seem that if I could boost the incoming water temp by 10- or 20-degrees (or more?), the tankless heater could produce a higher GPM rate more easily. This would be in lieu of totally replacing our 13 year old tankless (3.6 GPM for a 70-degree rise) with something with a higher GPM.