Diagnostic Tools-Indoor Air Quality

There are currently a few hot topics around the construction industry, the high efficiency heating and cooling system called a heat pump is one of the biggest.  Cross laminated timbers (CLT) are an engineered wood product that is getting a lot of attention in the commercial side of construction.  I’m hearing some noise about a few builders wanting to try the technology in the residential market as well.  And then there’s indoor air quality.  Since the start of the pandemic, there has been a lot of attention on how to make the air in our homes more healthy.

There are several strategies on how to create better indoor air quality.  The three big ones are source control (the best way to have healthier air is to not have any sources of pollution in the home to begin with).  Dilution is another, mix the indoor air with outdoor air, (hopefully that outdoor air doesn’t have a bunch of bad things in it when it comes into the house).  And the last is filtration.  Filter the “fresh air” entering the home and recirculate the air already inside the home through another filter, most forced air heating systems have filters that scrub the air.  How well the different filters work is a topic for another time.

Working in building diagnostics and energy auditing, up until recently I only had a couple ways to check indoor air quality.  The first was simply using my nose as I entered a home.  We’ve all experienced odors when entering a structure. If the smell is freshly baked chocolate chip cookies, the alarm bells in my head are not going off.  But if the smell is musty, or I detect the odor of a garage inside the home, then I know there might be something going on in the home that is affecting the quality of the indoor air.  Sometimes the odor might only be in a small portion of the home, like the basement or closet.  Other times it’s through the whole home.  My nose usually doesn’t lie, if I can smell it, there’s probably an issue, but my nose will not quantify the quality of the air.

Another method is with my wearable carbon monoxide detector.  CO is an odorless and colorless gas that in large quantities is deadly.  Smaller doses can cause a person to be sleepy and/or cause headaches.  My small CO detector can help identify both the large and small quantities of CO, a useful human safety tool, but I have yet to detect a carbon monoxide issue within a home.

The last tool I would use is my humidity and temperature monitor.  High levels of humidity can encourage biologicals to grow in areas inside the home.  Too low of humidity can be detrimental to a person’s health.  Finding that balance between what is good for the home and what is good for our health can be very challenging, especially in cold climates.  

This is called the Sterling Chart and is a product of a paper called “Indirect Health Effects of Relative Humidity on Indoor Environments”.  The chart shows the best indoor humidity levels based on how different diseases and irritants are affected by high or low humidity levels.  For instance, the best humidity level to protect against viruses is between 50 and 70 percent.  Now, for perspective, if you try to subject a home in a very cold climate to a 50% humidity level during the heating season, that home is going to have lots of other issues.  The blue portion of the graph shows the ideal humidity level for most houses to protect against the majority of air quality issues that may cause health concerns.

Okay, back to the main topic of this post, until recently, the three “tools” I mentioned above have been my only way to gather information on the quality of indoor air during a building diagnostic visit or energy audit.  My newest tool just changed that.

This is the CPS IAQPRO SmartAir professional indoor air quality meter.  There are homeowner grade monitors (I own the Awair Element) that can be purchased for about half the cost of this unit.  Those monitors are designed to give a homeowner a basic picture and show trends of the different metrics they measure.  The SmartAir contains additional, and supposedly more accurate sensors.  (I have to trust CPS on the accuracy levels, there is no way I can verify this information.)  My understanding, this is one of the drawbacks with portable air quality monitors in general, the cost of laboratory grade sensors and monitors might be in the thousands of dollars, yet we can purchase some indoor air quality monitors for under $200.  We are probably not getting highly accurate data from these monitors, hopefully the information they are providing is close enough for us to see if the home has an issue or not.

The IAQPRO SmartAir produces information on several different metrics that effect indoor air quality.

  1. Carbon Dioxide (CO2)
  2. Particulate Matter (PM10)
  3. Fine Particulate Matter (PM2.5)
  4. Volatile Organic Compounds (VOC)
  5. Humidity
  6. Temperature
  7. Dew Point 
  8. Building Pressure

I’m planning a dedicated post covering these different metrics that indicate the quality of the indoor air.  For now, just be aware there are recommended limits for each of these metrics.

The information provided to my smartphone by the CPS link app during a recent test using the CPS IAQPRO SmartAir tool.

The IAQPRO communicates with an application on a tablet or smartphone.  Through the app, you are able to control several functions within the monitor and create customizable reports.  This tool was manufactured mainly with HVAC technicians in mind, a way for a technician to determine air quality and possibly make additional sales by offering options for increasing air quality.  My intent in purchasing the monitor is twofold, the first is to educate a homeowner on the benefits of good indoor air quality by showing the test results of their home.  (I’m not selling products to the homeowner, just making recommendations based on what I find.)  The second is for me to gain more knowledge in what to expect from homes in my area, especially when testing during the heating season.

You can purchase this tool at several locations online.  I purchased mine at Trutech Tools.  A great site to find many test tools used in both the construction and mechanical/electrical/plumbing (MEP) trades.

Stay tuned for future adventures in using this tool and what I’m finding during testing.  And as promised, more information on what makes for good indoor air quality is my plan for the next blog post.





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