Avoiding Air Conditioning

Environmental Mission > LEED Gold Welcoming Center > Energy Conservation

Our Welcoming Center has no air conditioning system, and yet it remains the coolest building on site during the summer. By not installing air conditioning in the building, we save large amounts of energy during the warm months. There were various factors that allowed us to avoid air conditioning. The high thermal mass of the building helps keep the temperature down when it’s warm and sunny out by absorbing excess heat, while the living roof reduces the “heat island effect” that occurs with the black tar roofs found on most commercial buildings.

One of the ways we avoided air conditioning was by going back to "low-tech" solutions for keeping the building cool. There are plenty of ceiling fans to keep the air circulating as well as "operable windows with shading devices," a fancy name for good, old-fashioned windows that open and close and have coverings to keep out the sunlight when necessary.

In addition to our low-tech windows, we also have some high-tech windows, which are part of our demand-controlled ventilation system. If you look up at the ceiling in our dining room area—the central and also largest part of the building—you will see a row of smaller windows on the north-facing side of the roof (away from the sun). These windows open and close automatically depending on need. There is a sensor (also in the dining room) that tells the windows to open if the inside temperature is above 68º F and to close if it is below. This allows the hot air, which naturally rises to the top of the room, to vent out, keeping the building cool. The other part of our demand control ventilation system is a CO2 sensor. This does not serve to keep the building cooler but does regulate indoor air quality. This sensor determines if the levels of carbon dioxide in the building are too high (which can happen in the winter when the windows are all closed to keep the heat in), in which case air is pulled in from the outside until the levels return to normal.

When all else fails, we have an evaporative cooling system that takes the place of a typical air conditioning system. The evaporative cooler (also known as a "swamp cooler") pulls air from the outside through an earth-sheltered basement—pre-cooling the air—and then through a membrane that has water flowing over it. This cools the air down before it is blown into the interior of the building. Swamp coolers use about 75%—80% less energy to operate than an equivalent refrigerated air conditioning system. Our savings are in fact even greater because our other building features decrease the need to run an air-cooling system in the first place.