I'm sure there's a simple solution, but I've been wondering how to resolve this problem.

I plan to buy a storage water heater, which will basically serve 2 bathrooms in the house (4-room flat). Was planning to have 2 switches (1 in the masterbedroom toilet, and the other nearer common bathroom in kitchen). HOwever, if both bathrooms are used, how will I know whether the heater is on or off (without having to check the position of both switches?). Some have suggested only one switch, but also not very convenient for guest to flip switch located in masterbedroom, or for us to walk to the kitchen to switch the heater on for a bath in the master room.

Any solution? TIA!

i'm not very sure, but i have an impression that you can't have a 2-way switch on heaters...

Two way switch for water heater spoils very very fast.

Just install 1 switch. How often guest come?

If seldom, then during their visit, u just leave heater on for a few hrs during peak period.

I suggest having 1 switch positioned just outside the MBR. It will be convenient for all and also it will be easy to check if the heater is on or not.

Use master room as a master switch.

The other as a salve switch.

If master on, heater is on.

If master off, even the other switch is on, heater is off.

The common toilet switch is just a salve switch.