I would not do special motorized zone damper in a rental. 

If you are wrong and things motor along as they have been - you have a way to access off-market properties before they hit foreclosureWin-win

I've had one estimate so far and the guy said that he "exhaust motor" needs to be replaced.

Hmmm, I'm thinking the motor city could become the BiggerPockets City!  

That's relevant because the city that was the "arsenal of democracy" became "motor city," it has now  become in no small part "mortgage city" (there are people who's families have literally done that transition, across a few generations, from grandpa building the bombers to dad building the cars to kid putting together the mortgages). 

(House was in Highland Park, Los Angeles)Purchase price: $600kRehab: $94k - Full rehab: new layer of shingles on roof, 13 new windows, all new doors, new laminate floors, new 3' front retaining wall, full gut kitchen (new cabinets, quartz countertops, tile backsplash), 2 full gut bathrooms (new tub, floor tiles, wall tiles, vanities, faucets, toilets, vanity lights), converted one closet into a washer/dryer closet, created a master ensuite with a hallway bath, opened up some walls, recessed lights throughout, scraped popcorn ceiling, installed new HVAC, interior paint, exterior paint, stucco repair, new landscaping front and rear of house, new wrap around deck, installed double french doors master bedroom and garage, to new tankless water heater, new exterior lights, updated light plumbing and electrical, new garage door with motor, and some other normal repairs like replacing drywall, floor boards, and replacing some wood trims like facia boards.    

Its like saying I want 3 cars, so grab 3 cars out of the junkyard and put motors in them.

That said there is also items such as a $750 variable speed blower motor I replaced in my HVAC system this spring, that is an expense as it is a component of a larger system.It is very complicated and that is why clients pay accountants like myself to keep track of them and assist.You are not going to depreciate a $40 light fixture it will be expensed when you replace. it.

Hardly anyone is goofy enough to buy 5 house on one lot or an old motor lodge.

Hardly anyone is goofy enough to buy 5 house on one lot or an old motor lodge.