Energy Efficiency | January 30, 2020

The Impact of Oxygen In Your Office

Sitting in your office in the winter, do you ever feel a little sleepy?  Ever think to yourself, "why am I tired at work?" This might be due to shorter days, overindulging during the holidays or not enough coffee. Or it could be something else. Turns out, your HVAC system might be compromised. The two main reasons HVAC can cause drowsiness in an office are: a maintenance issue (something is broken or blocked) or someone is using the wrong rationale.


Common Maintenance Issues

Checking fans in industrial or commercial spaces means starting with the basics; are they on?  Why are they off? Is there damage to address? Has someone blocked the rooftop unit? Is there a filter that needs to be changed? We sometimes hear, “it’s always been this way.” The air changes per hour required vary from room to room and are subjective (within standards). While some rooms need 10-12 air changes per hour (air moved into or out of a space) some spaces need upwards of 25 air changes per hour. Regulation around hospitals, biomedical centers, vivariums and manufacturing facilities are enforced at a higher standard than many office buildings.


An Incorrect Rationale

When the temperature outside is 40 degrees lower than you want it to be inside, it makes sense to recirculate the air inside which is already warm, right? Why would you want to heat cold air from outside when you could easily maintain the current temperature? The answer is oxygen.



If you block the fresh cold air from coming in, then you also stop bringing in the fresh oxygen as well. The less oxygen you have in the room, the less energy you’ll feel because we all need to be able to send oxygen to the brain to function.  It makes sense that an environment with lower oxygen levels would slow you down, and possibly leave you drowsy.


HVAC, Oxygen and Energy Efficiency

So how does this connect to HVAC? Recirculating the same internal air or not having enough air room changes per hour, even if the temperature levels are easier to maintain, will gradually decrease a building’s oxygen levels and increase ever-present carbon dioxide in the air. Although extremely unlikely, in severe cases hypoxia is possible. Maintaining oxygen levels efficiently is dependent on pressure and active CO2 controls.

While the “energy efficiency” argument might be to keep circulating air that’s already been heated, there are dozens of HVAC strategies available to ensure your air quality remains high while also not overtaxing your equipment. These include optimizing rooftop units, re-engineering the process of recirculated air and exhaust systems, and perhaps obviously, don’t block the vents. If you want us to look at your system click here to have us do a zero-cost analysis of where your building could use efficiency improvements—not to mention save you $$$ in the long run.