For A/C, summer months will use more energy and less in the winter, and vice versa for heat, but you can spread the average across all months, similar to the programs energy companies manage so users don't have large swings in their bills season-to-season, and add this to the monthly rent for each unit based on square footage, # of occupants, etc.

However, the most efficient way is to build relationships with brokers and property management companies.

What are good ways to invest in efficiency?

I tried to show most of the important data points so that you guys can look for possible investments using the bathroom in the most efficient way possible :)Also..

The more time we have to spend online, the more efficient we want to become by using acronyms.

Is it efficient?

Your better bet is to market to these clients now and when you find a motivated seller, negotiate the deal.I am a financial advisor that works in the energy corridor. 

Also being my own agent allows for more efficient negotiations and I would know exactly what is going on, not just a play by play from an agent.

Will any efficiencies of 1 bldg offset costs of having 3-4 separate 4-plex’s?

I don’t feel it’s efficient to say the least.