so as stated above.
The size you need and cost increase will be due to usage.
retrofitting gas lines can be expensive.
220 volts could be used instead of gas.
But the key thing most people miss is that the units are based on temp difference.
They mostly can only do a 40 degree temp increase as it passes through the system.
That is what you need to check on.
I mostly used them overseas, where the outside temp was in the 70 at night and incoming water didn't get much colder than that.
But if you get 50 degree water coming in and you only get a max of 40 degrees up, then you get 90 degree water coming out of your shower.
not going to cut it for most people.
payback is also a hard pill for most to swallow.
An installed water heater tanked is maybe going to run 1k depending on how big and fancy it is.
A tankless unit that can accommodate 2 showers and maybe laundry is going to cost well over that just for the unit.
https://s3.amazonaws.com/s3.supplyhouse.com/product_files/Rinnai-RU199IN-Temp-Map.pdf this one says it can handle 35 degree water
https://www.supplyhouse.com/Rinnai-...QPg7-gI3ubQpnrCqphMTw_o78z0aAgJ2EALw_wcB but it runs 1700 just for the unit.
https://s3.amazonaws.com/s3.supplyhouse.com/product_files/Rinnai-RU199IN-Product-Overview.pdfat the bottom shows the delta it gets based on flow.
