Not sure if it was disabled because the battery needed to be replaced or if it was disabled at a time of a false alarm. 

Personally I like the ones with the built in batteries - saves tenants from themselves when they don’t change the battery. 

Several tool boxes with wrenches, screwdrivers, pliers, socket sets, flashlights, spare batteries, nuts and bolts, screws, electrical repair parts, multimeters, copper/pvc/galvanized plumbing repair materials. 

Each owner/client has a vetted resource I have provided who does the physical inspections, changes AC filters, changes out smoke detector batteries when scheduled, and documents any repairs/improvements/issues.

This also gives you the opportunity to inspect the property in general, but batteries in smoke alarms and CO detectors.

Your time is much more valuable spent lining up the next deal, rather than worrying about remembering to call the handy man to go change the HVAC filters and batteries in the smoke alarms.

It's called Landlord's Cash Flow Analyzer Pro and it costs $99.95 (it includes everything but the IRA module).https://www.rentalsoftware.com/real-estate-investing-software-features/Another really popular one that a lot of syndicators use is Syndicated Deal Analyzer, which was created by Michael Blank. 

Mitsubishi has a wired module adaptor that allows a standard wall mounted wireless thermostat to connect to it.

. - We decided not to replace the existing boilers with high efficiency modulating condensing boilers.  

Would like to hear from other agents and investors who deal with this type of commercial assets..  20 years is short, you'll earn a return and own the land if you want to convert to charging stations, battery swap, etc.