Air conds are provided by you?
Anyway, you did a very big mistake here.
If I were you, I'll measure each appliance's maximum draw(set to lowest and blower speed at max) for 2 hours and take measurement. Like if 2 hours using 2 units, then 4 air conds will use 8 units for 2 hours. 1 day would be 48 units. 30 days will be 1440 units. The water heater, WM and others. Get the average out and calculate.
Then from there you set a price of a room rental, this can avoid your problem.

Nope, I never think of this. But my friend have this problem from people that rented his properties.
For me, if were to avoid any problems, water and electric meter I won't provide, simple. Only can't ask for high rental.

If the tenant wants to default, nothing much you can do.
So for peace of mind, I'll cut everything.

Always try to think what your tenant will do(is not their property, so they won't other to take care).

For me, I'll just sell and keep the money in banks for FD. Sometimes the yield are better. But provided you don't use that money.

money do depreciate over the time. But if you don't have money, it is worst.