wording for unreasonable overuse of utilities in rental agreement in new york?

This has nothing to do with what the previous tenants used, that would be unfair and would not necessarily be to your advantage. Contact your power company and they should be able to tell you what average usage is for the square footage and appliances your unit has. Of course if you have equiped the unit with newer energy efficient appliances your tenants will use less and the bill will be smaller. Then you inform your potential tenants what the power company says about average usage and let them know that usage in excess of that plus say 15% for two or more consecutive months will require them to reimburse you for the overage. Because this has to be averaged out over the seasonal changes (more lights on for more hours plus heat in winter - less in spring and fall but more again in summer because of air con.) in usage you must allow that 15%. If you see something like a pattern in any changes you should also have the appliances checked for malfunctions.

Sorry if this seems confusing but at first I thought you were the land lord but on second read it sounds like you are the tenents. Same process applies.

Dont know if you are in the City or elsewhere but . . . .