I actually jumped the fence from the neighbors yard and cut the power to the compressor. 

You need a compressor for the hopper gun.

The problem is individual electric metering.Is it possible to run lines off one compressor  to units in two different apartments and somehow meter them for their individual electric use?

The outside compressor can reverse so instead of the inside evaporator coil getting cold (AC mode), it gets warm (heat mode).

The concrete dust from drilling the holes should be blown out with an air pump (best to use an air compressor) so the epoxy has a good bond.

If you install two units, would that cost $15k for everything (2 units, compressor, vents, ducts, permit, etc)?

Thanks.A restricted evaporator, due to a dirty, or non-existing filter (resulting in a dirty evaporator coil), is one of the best ways to kill a compressor.

If you are looking to save money, just pay them to change the compressor itself inside the condenser.

Replace battery is necessary.(9) Test/Reset GFCI receptacles.(10) Test outside hose bibs and main shutoff valve.(11) Visual inspection of ceiling for stains.(12) Replace burnt out light bulbs for elderly tenants with no ladder.Then every 6 month or so I would do a few additional things such as wash down AC compressor coil; open the tub drain and bathroom lav drain stopper and tease out the hair down there; may be do a test load of wash and dry if I have some dirty rags in the back of my vehicle; get on the roof for a visual check, open the main sewer cleanout outside and shine a flash light down, and obviously I emailed tenants before each visit to see if they need me to look at anything. 

So that'll be my compressor finish nailer retired soon then.I don't know about the other manufacturers, but a few months ago I bought one of the newer Milwaukee Fuel impact driver - OMG - how powerful is that?