You may want to research the Clean Air Act.

What can I do moving forward to prevent this and make it a success for me and the building ?

Hey guys,

so i need to add an AC unit to my multi-unit property in Ontario.
I was wondering if people usually prefer to rent these or buy them?
I did the math and based on the quotes if I buy i make my money back...

If they are larger you will need to skim with a leveler to prevent transposing. 3.

Your point about the potential for downward price pressure that would prevent you getting your refi is a real concern and this is how I would see it. 

Additionally, I'll put language in the lease specifying quarterly inspections/air filter changes. 

I was also thinking about doing the same, but renting it out as a short-term rental (air bnb/vrbo) when I wasn't using it.

Lower unit: new floors, texture and paint walls, new light and plumbing fixtures, new doorsUpper unit: making a larger kitchen with an open concept living dining and kitchen, new floors, rock, tape and paint throughout, new trim and doors, new cabinets and new bathroom New windows and siding, 12x12 decorative concrete patio for each unit, new concrete floor in garage, new driveway, removing elec baseboard heat and putting naturally gas forced air in both units.

I told the owner about the water leaks and the wet carpet he cut the wet part of the carpet and left it for 5 months, it was dirt particals in the air in the apartment from the carpet.

Typically, this will prevent you from wasting your time showing to unqualified applicants.