Why would anyone, in their right mind, consider paying for someone else's usage boggles my mind. 

I would appreciate you removing your mean and inappropriate cartoon, Mr.

There is a happy medium, the energy star usage data is pretty easy to find if you look up the model online and it shows you a range of the energy usage of that model compared to the most and least efficient models. 

For frequent usage and a lot of doors and users, it's worth it to go with the professionally installed system - it might set you back about $1,500-2,500 per door, and will integrate with your security system and fire panel.

Around here, a natural gas bill is about $45 per month with no usage (just all the fees and ready to serve charges).

Once a year I adjust escrow payment to match usage. 

Look for waste in utility usage or repairs costs due to old/outdated mechanicals.If your using a bank how much do you have to put down ? 

And because the O&G workers aren't at the rental unit half the time their usage is typically lower than if a 'regular' tenant was there all the time.

This incentivizes everyone to not be ridiculous in their utility usage. 

People can have their political beliefs, but posting them in public in an inappropriate way would get my attention and concern also.