tank inline with tankless water heater
I currently have an electric tankless water heater. I went with electric as we also have solar power on our house making electric free most months of the year :) House is in NJ and there are 2 adults and 1 newborn. We strictly use low flow water faucets/shower. 1.5 baths.
Here is the issue... Our family recently expanded (the newborn :). The electric tankless is not able to keep up with the GPM in the winter months - especially now that we have a lot more visitors.
So, I have a few options: get a gas tankless, gas tank, or a combo of tankless and tank - would that work?
Here is my thought process, please correct any bad logic... Rather than scrap my electric tankless, I'd like to still use it to do most of the water heating. The path would be cold water --> tankless (heat up to 90 degrees or so) --> gas tank water heater (probably a 40 gallon, heats from 90 to our desired 115 degrees or so). My thinking is that we will still take advantage of the "free" energy to heat most of the water, the tank will then help us cope with the additional GPM by keeping the rise of the water more reasonable for the tankless. There will be the added benefit of no hot water lag.
Will this work and be efficient? My goal is to limit the amount of gas used as much as possible while preserving our initial investment. Will a tank water heater be OK with inlet temperature of 90 degrees? Will this have a noticeable energy savings over just a tank style heater?
Thanks for your insight.