Shared laundry but without "common area" meter

[Bowman Klinkenberg]

I recently purchased a duplex with separate electric + gas metering for each unit. I'd like to add shared laundry in the basement, but don't have a third "common" meter for either of those utilities, so I'd have to hook up gas + electric from one of the two units to accomplish this.

Since the gas and electric are separately metered for each unit, I'd prefer for tenants to pay for those utilities directly and this is common for my area, but have concerns that one unit would pay extra in utility cost for the shared laundry while the other unit got it for "free."

Do you have suggestions on how to handle this? I might consider a specific credit or just adjust the rent for that unit accordingly and inform the future tenant that their utility bills would also reflect the laundry. Both units are currently vacant, so I have flexibility to include this in new leases however I need to.