Outrageous energy bills

Greetings. My partner and I have a park where it appears some of the tenants are faced with $400 electric bills. We’re relatively new to this so it’s come as a shock to us that a home this small (relative to a house) can rack up a bill like that. At first glance it looks like the unit is a little undersized and perhaps a window or two may need to be checked for leaks. There’s no gas heat here so that hurts as well. Nonetheless, it seems like the amount is excessive even for a inefficient home.

How do we get a thorough diagnostic of a particular home so that we can help these tenants lower there bills? I’m not sure the utility company themselves would perform a unit wide once over.

This even poses another problem when a new tenant has to put down a deposit that represents a typical month in that unit with the electric company. They turn ashen faced when told it’ll a $400 deposit. We’ve lost one on this very issue.

Any ideas on how to lower the power bill for these tenants is greatly appreciated.