With the cost of materials, it is kind of goofy to do a 225 amp as to a 320 amp service (2 200 amp panels sharing a 320 amp meter. 225 amp would be a little bit bigger wire than 200 amps, I think the panel would have to be a commercial grade panel with a custom main breaker. If the tankless is pushing on needing a 225 then it may be a better idea to do the 320 amp (commonly called a 400 amp service). If you are sure on not using tankless, just do 200 amps, the extra 25 is really a minimal amount that was only useful to meet the minimum load calculation for having a tankless water heater.

I am not sure 225 would do it with a tankless depending on how it is sized. I have seen more than one that was sized to run almost every hot water supply in the house which is nuts. Who needs to do a load of dishes and laundry at the same time while each shower/bath is being utilized or should I ask how often if people in the house communicate and time the usage.

The marathon water heater by Rheem is the best deal in my opinion for an electric water heater. The tank is poly so it will not rust out and has a lifetime warranty and the elements and thermostat have a 5yr warranty I believe but are all easily serviceable even if wires need to be replaced in the unit. The price point is high but usually utilities have rebates or have discounted prices for them.

I think normal price is around $700 or so and going through my utility I can purchase one for 500 on a 50 gallon heater.

The cost seemed high but the peace of mind of not having to lug another tank downstairs or having a blowout from a rusty tank would be nice. These units also have a very thick foam insulation layer.

Just some things to consider, and when I replace my heater it will be with a lifetime warranty tank.

Here is a link that might be useful: Marathon hot water heater