Fume Hood Shut the Sash Pilot Program
Is your fume hood alarm going off?
Please shut your sash!
Check out our Shut the Sash initiative below and our other Pilot Programs. We hope these initiatives will make your lab safer and more sustainable! Check out our other fume hood posters here!
Fume Hood Shut the Sash Pilot Program
Fume hoods account for 40-70% of the total energy used by laboratories.
As such, campaigns working to change behaviours surrounding fume hood sash closure make labs not only more energy efficient, but also safer. Here, Caltech Green Labs proposes a summer-long campaign to collect data, educate, encourage behavioural changes, and assess success of a "Shut the Sash" campaign.
To run this project successfully, we intend to use help of student interns. All data collected during this competition will be presented to the community in various forms, including (but not limited to) during the Green Labs Lightning Talks Event. We expect to see savings of around $1,250 per fume hood!
In a study published by MIT, the addition of homemade Motion and Sash Height (MASH) sensors, which alarm when the fume hood is open and unoccupied by a user for a set amount of time, encouraged users to close the sash and resulted in a 75.6% decrease in average sash height as compared to control groups that did not have a MASH sensor installed. As a result, the energy costs of running each of the fume hoods was reduced by $1,159 per year. We hope to see similar results if such a campaign was implemented at Caltech, making users both more efficient and safer while working in or around fume hoods. In addition, we hope to build upon the original study by incorporating data collection capabilities.
Each homemade MASH sensor costs around $20-$50 to build and are very simple to build and install. They include a distance sensor to measure the height of the sash, a motion detector to detect if a user is present or not, a buzzer to alert users if the sash has been open for 5+ minutes without a user present.
We hope to build and install 50 MASH sensors in various buildings across Caltech. We will preferentially choose buildings that have a large number of variable air volume (VAV) fume hoods that are ideal for our study. In addition, as part of the campaign we will coordinate with lab managers to increase awareness about the program, educate users on proper fume hood usage, and educate users on how the MASH sensors work. The MASH sensors will alarm if a fume hood is left open for more than 5 minutes without a user present, alerting users to shut the sash. Furthermore, participating labs will be entered into a raffle to win donuts for their entire lab!
Our plan: Utilizing the help of one intern over the summer of 2024, we hope to build 50 sensors for installation. Before the sensors are installed, we will work with lab managers and PIs to gain permission to run the study, educate users on the safest and most efficient way to use their fume hood, and explain the competition. After a few weeks of baseline data collection, the sensors will be installed and subsequently the alarms will be turned on. Signs will be posted near the fume hoods to inform users of the function of the sensors and course of action to take if the alarm goes off. Education will continue after the program to encourage users on best practices. Our intern will present their work at the annual Green Labs Lightning Talks event, and will produce a writeup describing the campaign results to share with the community.
Fume Hood Hibernation and Turndown Program
Green Labs has also come across many fume hoods that are over-ventilated or underutilized!
As such, we've begun a hibernation and ventilation turndown program we estimate will save over $100,000 annually for Caltech. As of April 2026, we have hibernated 27 fume hoods and are planning ventilation turndowns for all buildings that have fume hoods throughout the summer. If you have a fume hood you would like turned down, downgraded to use for storage only, or hibernated, please reach out to us at [email protected].
Hibernations are underway! If you see this sign on a fume hood, know it has been hibernated (and is not pulling any air away from a user!).
Any fume hoods with this signage can be turned back on again if ever needed by contacting Safety and requesting the fume hood be un-hibernated.