Shared electricity on two units

[Albert Johnson]

On one of my units the property has shared electric with another unit I own. One of the units has a submeter and the other doesn't. 

The tenant that receives the electric bill is the tenant that does not have a submeter. They moved in 2 months ago. This tenant complains that the bill is extremely high. 

The tenant that has a submeter moved in this month. The submeter is accurate and tracks usage of anything powered on in the unit. 

Does anyone have experience with tenants on shared electric?

How did you handle this with one tenant complaining there electric is high?