“We have an on-going issue of people constantly changing the temperature. One office might be warm whereas another office might be cool. When the thermostat is readjusted, it messes up the temperature for everyone in the building causing more battles for controlling the thermostat!”
-Insight from a TherMOOstat user
Who touched the thermostat?!
Have you ever taken sides in a thermostat war? Or are you neutral like Switzerland and come to work with an extra wardrobe to adapt to the office climate? In this post you’ll find out a little more about what’s happening in the heating, ventilation and air conditioning (HVAC) system that can make these wars so intense.
In any given building on campus there is an HVAC system that controls the temperature and airflow in the rooms. However, every building is a little bit different in how the HVAC system serves the rooms. In bigger buildings, the space is typically divided into different zones. The number of rooms in each zone can vary, but there is typically one thermostat per zone, the prize everyone strives to control in a thermostat war. Lastly, within each room, the number of people, and their demands upon the system can vary.
The first offense
The outside air temperature is beginning to drop. It’s a high of 55 degrees F outside, and when Sara gets to the office at 7:00 am she raises the thermostat to 73 degrees F.
The HVAC system supplies warm air to the space Sara is in, but she’s not alone. Sara’s desk is in a large open space of the building (Room 1200), which accounts for one HVAC zone and has ONE precious thermostat.
Above is the layout of the Rifle Range, the Energy Conservation Office’s home turf. We’re all about saving energy, but let’s face it, sometimes thermostat wars are inevitable. As you can see, Sara sits in the same space as her co-worker Dan, who is about to arrive to work.
The second volley
Around 9:00am Dan gets to work. He just rode in on his bike and even though he’s taken off his jacket, scarf and hat, he’s still hot. So Dan walks over to the thermostat and thinks, “73 degrees! I don’t think so!” and he commandeers the thermostat, lowering it to 68 degrees F.
However, when Dan changes the set point on the thermostat, well you already know… he’s changing the set point for all of Zone 2.
The skirmish has begun
Sara feels a draft in her workspace and starts to shiver. What’s happening behind the scenes in the ductwork of the building is a fluctuation of air temperatures that is not peaceable or energy efficient.
Let’s extend this concept a little wider:
If 10 offices are in one zone with one thermostat, one person changing the set point to over cool a space can waste energy in the entire zone. This is bad, but now consider multiple zones in one building. If one zone has a low set point that is calling to the HVAC system for more cooling, the air handler in the HVAC system must supply cool air to every zone. For the rest of the zones that don’t want that set point, the cool air from the air handler is re-heated to their desired temperature. So not only is the one zone being over cooled, but the entire building is now being overcooled and spending energy to re-heat the other zones. This is a serious issue.
If you’re left wondering why Dan and Sara just can’t get along, consider yourself lucky. Every building is different. Some buildings have more zones than others, sometimes there’s one thermostat to one zone and other times there are multiple thermostats to one zone. What this means is that rarely people get to change their own temperature, and we need to adapt. Don’t stop reading just because that’s not what you want to hear. We’re not here to rain on your parade. We want to hear from you about the temperatures in your space. Submit thermal feedback via TherMOOstat and we can track when you’re uncomfortable. We want to investigate why your room may be chronically warm while your neighbor's chilly. At the same time, we want to share with you why it’s happening and what’s going on in the HVAC system.
For those who have thrown up the white flag in a thermostat war before, we salute you. Adapting to indoor temperature can actually be more difficult than adapting to the weather outside. Moreover, you’re likely helping save energy on campus and making allies galore. You’ve gained a valuable skill that will help us save energy on campus, and will help you save energy at home too.