Arkansas HVACR NewsMagazine March 2024

HVACR NewsMagazine March 2024

Tech News

The 5 Factors of Ventilation

Ventilation Strategies: ERVs, Dehumidifiers, and More By Emily Gutowski

It helps to think of ventilation as a combination of five things that all affect each other:

Circulation

Ventilation is largely about air movement, and circulation describes the paths that the air takes. We can think of circulation in a few different ways. Circulation may refer to how air mixes within a room. It also may refer to the way air moves between rooms. Some HVAC systems are better at achieving those than others; for example, mini-splits aren't typically great at either without help from something like a ceiling fan. Air moves between rooms due to pressure differences between those rooms. (Remember: as with temperature, air molecules will want to move from areas of higher pressure to lower pressure until they reach equilibrium.) As air moves through an HVAC system and is redistributed throughout the home, we want to remove things that are bad for our health, like cooking fumes, bathroom humidity and odors, and general dust, dander, skin flakes, and other particulate matter. Capture is basically spot exhaust in kitchens and bathrooms. Filtration allows us to remove those things from the air everywhere else, but we need to be careful about using a filter that has a high enough surface area to remove as many particles as possible without impeding the airflow. Once you know how you'll capture those contaminants, you need to circle back to circulation: how are you going to distribute and circulate that filtered air? Capture & Filtration

Ventilation is the V in HVAC, but it's the one that we seem to talk about the least. And when we do talk about it, it's often in very specific contexts, like ASHRAE Standard 62.2 (fresh-air ventilation standards in low-rise residential buildings). However, there's a lot more to ventilation than just bringing in outdoor air. Ventilation boils down to air movement, especially into and out of a space. Proper ventilation is a key element of indoor air quality, which directly affects occupant health and safety, and it can be affected by the ways we bring in and exhaust air, duct design, and the building envelope itself.