Shared Gas Meter!! HELP!!!

[Andres Perez]

So my offer on a duplex in Delaware County, Pa got accepted today. The property is in great condition but has one problem. There's only one gas meter for the property. There's also one water heater and one furnace. Now my question is how have investors dealt with this in the past? Can I get a device to track the percentage of usage between each unit and bill the tenant? <<< (Is this legal?). Should I raise the rents and pay the heat bill myself? Or should I get an estimate to install a separate meter and other worked needed to separate them? Please share any information you have. Thanks in advance :)