Recently, the meeting room I use for monthly design meetings with my client was getting really warm once we closed the door. This seems like a nearly ubiquitous issue: HVAC (Heating, Ventilation, and Air Conditioning) systems seem to often have issues where they tend to be too hot, too cold, too breezy, or just too complicated to configure. Our system at least looks a bit complicated, with a maze of ducts and vents between rooms:

Once the doors to the meeting room were closed, the room temperature increased from about 72° F to 78° F or more within about an hour. Not only was it uncomfortable, it was also difficult to be insightful or productive (or even coherent) when considering intricate design issues.

During several monthly meetings, I asked the operations department for assistance with the temperature. The first time they had a repair team come, and they found a broken freeze sensor--it was repaired several days later. At the following meeting, another issue was discovered and repaired. After this, the president of our company suggested that it might be better for me to do some testing before the client arrived. She added that it seemed like the room heated up once the doors were closed and airflow through the doors was blocked. I had been thinking that the room heated due to the number of people and computers we had. If it was true that the people were not the main factor, it was a great idea to do some testing ahead of time.

I'm an experimental physicist by education. Therefore, a few days later, I set out to do an experiment with the temperature of the room. I first closed all the doors, noted the temperature, and turned on the lights to simulate the heat of a group of meeting attendees.

When I came back half an hour later, all the doors were open. This room is a common shortcut in our office traffic pattern, and obviously people were smart enough to notice that the room was empty.

So the next step was to put up some signs--but I wasn't quite sure what to write on the signs. I felt a bit silly saying I was doing some sort of HVAC testing, but I couldn't think of another term for it, so I just went with it:

I put those signs up (on all five doors to the room!) and closed the doors again. After an hour, the temperature in the room was already up to 78 degrees F. I was surprised by how fast it went up even without people!

I let the operations folks know what I had found, and they looked into it. They found that the thermostat we had been told controlled the room did not--actually a thermostat in a coworker's office controlled it, despite the fact that his office is fairly small and quite far from the meeting room. They also found that a damper was stuck closed--they fixed this also.

Interestingly enough, the signs generated a lot of interest and discussion. Most people were quite interested in what type of "HVAC testing" I was doing. There was some question whether it was research about how the system worked or how to improve it. I explained that it was just a simple test to verify if the system was actually working, and to get it fixed if necessary.

After this round of repairs, it was time to do another experiment. (This time I knew enough to put up the signs at the start.) Happily, even after several hours, the temperature had not changed more than 0.3°. (It started at 71.9°, and rose to 72.2°.)

At this point, I'm hoping that it's really fixed, but we'll see. Things can always break--which will mean more HVAC testing!