Theres 2 main elements.

Only "Absolute 0" is, if getting anally technical, actual 0 degrees as in 0 heat of any kind. 

Probably they don't or you can watch them get heated up on the spot and make stuff up.Most of the national acts really seemed to be selling something else that probably won't help you.....database software for $30-100/month.   

If the lease requires Renters Insurance, do they have proof of the tenants current coverage4, Age of last update to the major systems (Roof, Electric, Plumbing, Heating)5.

Every state is different and section 8 adds an entirely new element to this. 

They're built inside a facility rather than being exposed to the elements.

Make a list of all assets and their components (how many roofs, refrigerators, heating systems, etc?)

The property had window AC's and a gas fireplace upon purchasing so we immediately had central heating and AC installed.

Most investors walk a building, identify windows and other benchmarks and rely on these elements in coming to their own conclusion on unit layouts and unit count.

When it is time replace your central heating and cooling system with split units.  10.