Installing Tankless Hot Water System - Amp Questions & Using AWG 6 Wire with Current Tank
Being a small home and only seeing 2 circuits (240v baseboard 20 amp heaters) you would be pushing the service, but it might work, you would be removing the double pole 20  in 1-3 and installing the 60 amp or going from 5kw to the new 13kw or April 8 kw higher draw or approx +33 amps while in use compared to the old one. We don’t actually add the breakers to figure out the total load on the service, where I could see a problem in the winter when you need full power on the water heater with the 2 base board circuits running the actual draw there could be right around 80 amps having the dryer or oven going along with some lights and you may trip the main. So it is very close. I would want to monitor the power usage with the above turned on and see what the actual draw is before saying yes or no.