As Charles mentioned, there are alot of tricks available, but the more units, the larger the numbers the more latitude the accounting system will have that becomes appropriate to improve performance.Point being, GE makes electric motors and alternators.

Our tenants have asked us to get HVAC service, as according to them the system is not as efficient.For context: this is a single family home we are renting out in CA while living in a different state.We did spend almost $10k this year to get pine trees cut down in the backyard, for fire prevention, which is not a cost we had accounted for when determining the monthly rent.We did change the motor of the AC in 2019, and from what I understand AC maintenance is not responsibility of the landlord.The previous tenants, did get HVAC service themselves.What would be a polite and tactful way of getting back to the tenants' ask for HVAC maintenance?

Isn't that a hotbed of a General Motors plant?  

Building dept can steer you to right info.In most states you register mobile homes with Dept of Motor Vehicles, just like a car and they can point you in the right direction, too.Have fun!

But I still hit WC every holiday season when I am in the Motor City!

In the last few years I have replaced a motorized trunk latch in the back and a starter so it has been running perfect.

With smoke if you don't cover 100% there will still be some there.Also not only the ducts cleaned but check the filters and the motor itself because if filters were left in to long then dust and particles have passed through to the motor.

Did Henry Ford run his business under his personal name or did you form a corp and run it as Ford Motor Corp?

You want the one that has a coil of cable and a motor, not the short hand powerd ones.

Shop was full if mostly junk, but back under a pile was a wooden crate with an camo painted outboard motor in it.