I know very little about legal precedent but I'd expect the major meter manufactures (selling into the utility space) to be well incentived to challenge these items best they can, and they have money.Here are the issues, and the reasons that the difference between an air forced system and a boiler/hydronic system are not meaningful for this discussion (ie efficacy issues of sub metering exist for either when method of measurement is measuring heat at point of delivery):In either case, the blower (or pump for a boiler) is the method of 'moving' either air (central air) or water/glycol or equivalent (boiler etc). 

Let me know if you need help leasing them.

Also the majority of those costs to covnert to a 2nd unit will need to be capitalized and depreciated, but some things (new appliances, flooring, paint, kitchen cabinets) can be shorter year assets vs. across the full 27.5 and IF it turns out that unit is > 50% you can use bonus as well on those items.

don't forget to get a lease...). 

Quote from @Ariel Rivas: I don't know your market specifically, but it's typically cheaper to purchase those items at Home Depot or Lowe's.

If you routinely try to get the next tenant in so quickly after the last tenant, perhaps you can add a penalty to your lease for holdover tenants.

Most of our tenants are traveling healthcare professionals, so we’ve tailored our lease terms to meet their unique needs.If a tenant needs to terminate the lease early due to their contract being canceled, we allow them to break the lease without a fee, as long as they can provide proof.

A lease.

Example mentioned already of shifting the leases to term out in the summer.

There's a lot for sale as well, and a lot for lease.