Utilities and the Lease

[Brian Wolf]

Hello All,

I recently inherited a tenant with a duplex I purchased. I am about to convert the one old oil furnace, used for both units, into 2 split traditional HVAC systems. Her old lease reads "The tenant will pay all utilities, except for the following which will be paid by the landlord: Oil heat, water & sewer." With this verbiage in place until January 2021 can I have her pickup this utility for the fall/winter as it is no longer oil hear but natural gas and also her own unit? 

Also, I was going to give her the option for me to add central air as well for an increase in rent, thoughts? How much is reasonable being that it would cost me an extra $3,000?

Thank you!