Boosting hot water capacity for tankless WH

[vitullostudio]

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.

 

[Terry]

It would make more sense to install two gas tankless units. Electric is kind of expensive.

 

[Sponsor]

 

[Reach4]

Vs an electric before the gas unit, it would make more sense to put the electric unit after, but set to a lower temperature. That way the electric unit would not turn on unless the gas unit was not keeping up.

But I would think that a second gas unit would be better if the gas WH often cannot keep up.

If this hot water is mainly for upstairs showers, you could run the drain water through a special heat exchanger in the basement that warms the incoming water for free.