Chemical fume hoods are found in chemistry and biology labs.  A single chemical fume hood can use as much energy as 3.5 households every day due to the large volume of air that must be moved through the hood by the ventilation system.  Broadly speaking, ventilation systems and fume hoods can be classified into two categories:  Constant Air Volume (CAV) and Variable Air Volume (VAV).  As these names suggest, in a CAV fume hood the amount of air flowing through the hood is constant, whereas in a VAV fume hood the amount of air flowing through the hood can be adjusted.  Because energy consumption in fume hoods is related to the volume of air flowing through them, reducing the air flow volume in a VAV fume hood results in energy savings.

Air flow volume in a fume hood is manipulated by adjusting the height of a movable sash, which acts as a barrier between the inside of the hood and the rest of the lab.  The sash should be raised when working in the hood, and in most cases the sash should be lowered when work in the hood is complete to ensure the safety of laboratory personnel.   In a VAV fume hood, lowering the sash also reduces the speed of the exhaust fan and the volume of air being exhausted by the VAV ventilation system.  The energy savings from lowering the sash in a VAV fume hood can be upwards of 40%.

To raise awareness about safety and sustainability for fume hoods, My Green Lab has begun a 'Be Good in the Hood' campaign.  The stickers below remind people to close their fume hoods. 

 












These stickers are clear (shown here on a cardboard box), and should be affixed to the fume hood sash.  To purchase these stickers for your lab or institution, please contact My Green Lab:  allison@mygreenlab.org.

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