Then call engineering department for water and see how much sq ft of room space is average consumption.

And that link also discusses cost-effectiveness vs savings in energy consumption over life of equipment.

I have entered a knowledge-consumption stage, and due to there only being so many hours in the day, I must be efficient with my time.

That fact that each tenant is responsible for paying all of their own utilities is in fact explicitly stated in their Leases.And, as a side note, I will add that after we implemented this system we observed that the building's water consumption dropped by 40%!!!! 

Link: http://www.zillow.com/homedetails/96-Summer-St-Waterville-ME-04901/84971756_zpid/So, what you think might be more like 1500 gallons in oil consumption will certainly change the numbers around.

If solar was really a sound investment, it wouldn't need to be so heavily subsidized which is part of my argument against it as a viable power source.Here's just one pro-solar summary:The average annual electricity consumption for a U.S. residential utility customer is 10,972 kilowatt-hours (kWh) per year, or an average of 914 kWh per month.

However, linens and towels and any appliances that need to replaced like a toaster is charged to the owner.If I am getting 12% to 15% of the gross income then I will generally charge the owner for all of the consumable unless it is a strategic property or owner that I feel very eager to land.In my experience covering the cost of the consumables is worth it as the items that are high consumption like TP and paper towels are not expensive if bought in bulk from CostCo or amazon (although supply chain is spotty during COVID as we all know)One thing I have noticed is that guests will buy kitchen items like soy sauce, tabasco, salt, pepper, olive oil, etc and leave them there so in a way the kitchen items are often "self-replenishing" but of course that is not 100%.

you are assuming consumers, will reduce the consumption for some reason.  

I am having solar installed in our AirBnB property here in Boston, ROI is about 3.5 years with current consumption. 

You generally get a minimum consumption with that type of billing, so it's apples to apples.