Our cars’ sensors and dashboards continue to provide us with more information. Why aren’t we using the same approach for ventilation – guiding our quest for healthy and energy efficient buildings?
Well, I have to say I am smitten with my new cars’ controls and dashboard. My favorite is the cruise control which automatically slows down when it senses the car in front in me is less than the distance interval I set. It will even break if necessary. My second favorite is the lane assist, which allowed me to take may hands off the wheel for a few seconds while I snapped this picture. I can look at another dashboard on my phone app and see my fuel level, if any maintenance actions are required now, and how many miles until my next maintenance. My app also gives me a weekly “Driving Score”.
Let’s compare this to HVAC operation. It’s incredible to think the vast majority of buildings don’t use metrics to manage or control ventilation rates (i.e. outdoor air rates)! With more emphasis on diluting aerosols (which carry virus particles), public authorities recommend facilities “increase ventilation” and “improve filtration”. Yet it’s difficult – no, impossible to improve ventilation rates if we lack metrics and feedback to let us know if ventilation rates are too low (resulting in poor indoor air quality), or too high (resulting in wasted energy).
That has now changed thanks to improved sensor platforms that, like in your car, measure and report key performance indicators for health and safety while optimizing energy consumption. Like speed limits and road conditions, ventilation requirements can vary throughout the day, week, or month. Some key metrics to consider: a) carbon dioxide (the amount of exhaled air that has built up in the room without enough fresh outside air to flush it out), and b) air borne particle and chemical levels which can be controlled by dilution and / or filtration. For example, if your ventilation rate is below the CDC recommended level of 800 parts per million (ppm) during normal occupancy (that’s good), yet small particles (PM2.5) regularly trend over 15 µg/m3 or 50 µg/m3 for large particles (PM10) it is likely your filtration needs improvement. Viewing trended data, not just at one point (spot testing) will provide superior guidance for better ventilation set points.
Today’s improved sensor platforms can also integrate with HVAC operation so ventilation rates will automatically modulate up for better indoor air quality and reset lower when dilution requirements are less to save energy. Just like speed in my car now is automatically adjusted with today’s cruise control settings. Welcome some feedback from readers on this.
More information: “Six Tips for More Effectively Managing Ventilation”