Did you know that Middlebury’s Bicentennial Hall has over 100 fume hoods? Did you know that, when open, each of these fume hoods can use as much energy as 3 ½ homes?

From introductory chemistry labs to faculty research labs, the amount of energy consumed by these fume hoods to ensure they run safely and efficiently is enormous. The easiest way to reduce a fume hood’s energy consumption and help Middlebury reach its Energy2028 goals along the way is to SHUT THE SASH!

What is a fume hood?

If you take a science course at Middlebury, there is a good chance you will use a fume hood. This piece of equipment is used to protect a student or researcher from the chemicals or substances they are working with. Simply put, a fume hood draws potentially harmful fumes or particulates away from the front of the cabinet and up and out of the building.

Why does it consume so much energy?

For health and safety reasons, labs use 100% outside air which must first be heated or cooled for comfort before it is circulated into a lab. Beyond the energy required to condition the air, a significant amount of additional energy is used to operate the large fans that move air through the building and the fume hoods.

Does Shutting the Sash Save Energy? 

Absolutely! Nearly all fume hoods at Middlebury are variable air volume (VAV), meaning the amount of air flow depends on the height of the sash. The higher the sash is, the harder the fan must work to remove the air, and thus more energy is consumed. Sash position is connected to BiHall’s ventilation system, so both fan speed and the volume of air moved is reduced when we shut the sash. 

When Should I Shut the Sash? 

Sashes should only be open when setting up, modifying, or performing an experiment. When the sash is shut, the fan will continue to work at a reduced level, providing some airflow through the hood to remove any lingering fumes. 

  • Finished an experiment? SHUT THE SASH! 
  • Taking a break? SHUT THE SASH! 
  • Leaving for the day? SHUT THE SASH! 

What Other Fume Hood Practices Reduce Energy Consumption? 

  • Never use a fume hood to just store chemicals – they belong in a safety cabinet. 
  • Place the sash in the lowest possible position to perform your experiment safely. 

Researched, written and designed by: Kristen Pundyk, Monique Santoso and Gabe Desmond