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Did you every wonder why we ask you to keep the windows closed? Well, here is a.. relatively.. short note on why. Enjoy!

So what about opening your windows for your office on campus?

Seems like a great idea right? Most people don’t want that musty and hot air coming from the vents when it’s nice outside. It IS nice to open your window when it’s 65 degrees outside and hear the birds and what …not. Right? As always there’s an opposing viewpoint to opening your office windows. Those of us tasked with heating, cooling, ventilating and dehumidifying your building would rather you leave your windows closed.

The building’s heating and cooling system performs several jobs. One is to heat and cool your space of course, but others jobs include taking the humidity out of the air and slightly pressurizing the building.

First let’s talk about dehumidifying the air. It’s more comfortable and less likely to grow mold in the building when humidity is less than 60%. It takes a lot of energy to do this though so we try not to go too far, only as much as needed to keep it safely below 60%.

The system also needs to pressurize the building slightly. That means it takes in more air than it exhausts which results in a tiny bit of air blowing out of exterior doors and cracks in the building. This helps keep unconditioned hot, cold, or humid air from entering the building creating drafts. It also keeps bugs out.

When we open our windows then the building system cannot properly condition the air nor can it pressurize the building. This is the stuff that causes concern for the building maintenance folks. It can actually result in higher energy costs! That humidity and hot or cold temperatures goes back to the central system treating the whole building. The system has to work harder and given enough open windows, can’t keep up.

Most of our heating and cooling systems on campus are designed to use 100% outside air when it’s cool outside. This saves energy and provides the ‘fresh air’ we all want. When it comes through the system then it’s monitored to keep the humidity low, it’s filtered to keep pollen and bugs out and contributes a great deal to energy conservation efforts.

So keep those windows closed and help the heating and cooling system keep the building safe, comfortable and efficient.

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