How to make tenants turn off basement lights?

[Nicholas Jose]

Good evening, BP.

So in the ground-floor of my property, I have washers and dryers, one set for the first-floor tenants and the other set for the second-floor tenants. The thing is, the first-floor and ground-floor electrical utilities are connected to each other, so if the second-floor tenants forget to turn off the basement lights after doing their laundry, the first-floor tenants will complain to me about how their electric bill went up.

How can I get the second-floor tenants to remember to turn off the lights in the basement without bringing up the first-floor tenant's electric bill?