In one of my previous roles as president of a very large credit union I built three separate branch offices, two of which were geothermal heated—one with the closed loop and one with the open loop geothermal system. The first was 45,000 square feet and the second was 95,000 square feet. One of the things we looked for there was a return on the investment, because it does cost money to be efficient.
Is there a guideline you could give of what you would like to see for that, or do you just collect data?