The Air Exchange is Now Open

As we welcome a new year, 2020 will go down in history as a one that most of us will want to forget ever happen. Words such as Quarantining, Social Distancing, Contact Tracing, Viral Load, and more are ones that we hope in the near future we will never need to hear again. But 2020 wasn’t all bad as we were able to bring some good words and phrases to the forefront – words such as Indoor Air Quality (IAQ), Air Exchange, Air Filtration and more. 2020 provided an opportunity to take a good long look at our living environment.

While Indoor Air Quality is not a new concept, it is gaining a lot of attention and will have lasting positive effects moving forward. Professionals in the HVAC and air movement industry have been working to improve IAQ for decades. Items such as better filtration in HVAC systems, more effective exhaust fans in the home, using range hoods and more have all contributed to a better living space. Now we are seeing and realizing that proper ventilation can play an important role in our overall health.

IMPORTANT NOTE: While studies are finding that a properly ventilated area (home, office, store, etc.) reduces the spread of viruses, it is not a magic solution that will 100% prevent it. It should be used as one part of a multi-part solution.

One aspect of proper ventilation is Air Exchange. First, let’s define what air exchange is. Well, it’s fairly self-explanatory – it is exchanging the air inside a home/building with air outside the building. Good air in, bad air out. The complicated part is how do we do this and how do we do this efficiently and effectively. The American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) recommends 0.35 air exchanges per hour. Let’s take a closer look at that number. If you have a 1,000 square foot home with 8 foot ceilings, that is a total of 8,000 cubic feet of air inside your home (for you engineers out there – yes the number will be considerably less than that because of walls, furniture, appliances and so forth – but just go with us on this for now). Take the 8,000 ft3 and times it by 0.35 and you get 2,800 (the quantity of air you need to move out of the home per hour). Now divide that by 60 (60 minutes in an hour) and you get 47. So to exchange the air at the rate ASHRAE recommends you should have an exhaust fan running at 47 cubic feet per minute (CFM) at all times. ASHRAE refers to this as continuous ventilation. Now, back to the engineers and numbers people out there. ASHRAE actually has a calculation for determining how much ventilation you need. Visit the ASHRAE 62.2 page to access the Air King calculator where you can input your information to properly calculate how much ventilation you need.

Now that we have how much air we need to take out of the home, we can concentrate on how much air we need to bring into the home. Using our example, the easy answer is 47 CFM and that would be accurate. The challenge comes in how we bring that air into the home. Many homes will have what is referred to as natural air infiltration. The average person knows these as drafts. This is air coming into the home without any outside forces working on it. With newer “tighter” homes drafts are greatly reduced so a different solution is needed to bring fresh air in. The simplest way is to open a door or window. While very effective, there are two challenges with this approach. First, this will only work in mild climates. If you live in Minnesota, you are not opening a window in February. The same holds true in Texas during the summer months. The second challenge is you can’t be sure the air you are bringing in is any better than the air already in the home. If you live in an area with high pollution rates or bad air quality, not exactly what you want to bring in. The best solution is to control as many factors as you can. Adding an air intake fan such as the Air King Fresh Air Series will bring controlled and filtered air into the home/building. You now control how much air comes in and can ensure that it is filtered. In more extreme climates using an ERV or HRV is another great solution as these are designed to bring fresh, filtered air in while reducing the strain on your HVAC system.

The main point of all this is that we need to pay a lot more attention to the IAQ of our homes and working spaces than we have in the past. Having a viable solution to exchange the air is a great starting point and a major component of an overall strategy.