I only run into Rheem water heater questions on days that end in the letter 'y'.
Dealing with an estimate right now.
An electric water heater from them just for a pool can take up to 3 240 volt 40 amp breakers.
Most instant water heaters capable of producing a hot shower are going to be of the three 240 volt 40 amp circuit type. Not only do you need the space on the buss bars of the panel.
The job I looked at on Friday has gas central heat in the house and had a gas pool water heater. However, the model they have chosen may work. 11 kW, a 2 pole 60 amp circuit. Main breaker is 150 amps. I did an amp draw and it was 24 amps. So, not bad. Working amperage of the unit is 45 amps.
Only problem is there is no easy way from the panel to the pool equipment. Panel is on a wall in the garage, back to back from the meter base. Equipment is on the exact opposite side of the house. 2 story house with no usable attic space.
Anyway, so, it is matter of how much service you have. Most modern houses have 200 amp service and the power company actually brings you 67 percent ( I learned from a lineman at Texas-New Mexico Power.)
If you have a big service, such as a 320, you might be okay.
Otherwise, stick with gas water heater with a 40 gal tank. Cheap to run. And just as ""green" as anything else.
