In 2009, I was fortunate enough to be doing mechanical engineering design work for the Cincinnati Zoo, and the Zoo was building three new buildings at the main entry–the Ticketing/Membership building, the Restroom/Stroller rental building and a large Gift Shop. The Owner wanted to use a ground source heat pump system for more energy efficient buildings, and also include a 10 kw solar PV array and an evacuated tube solar domestic hot water system for the restroom building. In 2011, I evaluated a year’s worth of utility data on the Ticketing building to see if we were getting the modeled energy savings (the building had achieved LEED platinum status and had a predicted energy savings of 80% over ASHRAE 90). We had installed energy meters on the heat pump panels so we new exactly how much energy the HVAC was consuming. In 2011, the energy savings over baseline model was 66%, which we were happy with. I revisited the savings again this year, at the end of 2016. The energy use for the heat pump system was holding steady, and the savings had crept up a little, to 70%. The site energy use intensity for 2016 was 70.7 kbtu/SF-year for the 3,070 SF Ticketing building. I looked around a little on the Energy Star website and couldn’t find much that I thought was a good comparison to see if that’s a low EUI, but I think it is for the type of building. It has nearly 365 days of use every year, with extended hours during parts of the year. It’s a small, busy building which is fairly densely populated. Also, Cincinnati Zoo maintenance reported that the system has been nearly maintenance free and they are very happy with it. The two buildings in the main entry which have heat pumps have Water Furnace and Climate Master heat pumps. They have been equally maintenance free.