Nick is a sharp investor U may want to see if he will engage you off line for some deeper dive in methods for success 

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). 

So when you buy your next property or use the brrr method, how do you typically finance it?

You should always look for Tax-Deferred and Tax-free methods to Invest.

The lease establishes the structure for how the tenancy should go so I would just keep my communication in line with that.

If you are considering using a more commercial method, such as a DSCR loan, those products are simply reserved for commercial use and not personal.

Have you thought about refinancing into a DSCR loan or have heard of the BRRRR method?

It varies a lot depending on install method, regional area, heck even a specific properties weather exposure. 

What matters more is whether the borrower in question has the (i) time, (ii) contacts, (iii) experience, and (iv) ability to effectively communicate & package their loan request to banks & credit unions in a way that is compelling to those lenders. 

Only one of these methods involves "saving" money, and most BP users don't pay enough attention to it.