Are Air Purifiers Worth It?
Years ago when I was pursuing my MBA I had to take coursework on something called CBA or Cost Benefit Analysis. It’s a 19th century concept that became particularly popular during the mid-Twentieth Century as a business strategy. It’s straight forward, a way of weighing project costs and benefits in order to determine whether-or-not to fund a project. Although many of us aren’t in the habit of incorporating business strategies at home, I was hoping you could indulge me for a few minutes as we walk through the CBA process as an example of how to determine if air purifiers are worth it or not. Granted, CBA is intended for analyzing projects, but let’s do a thought experiment and determine if the same strategy can be used for deciding when to make substantial purchases. Let’s face it, no one wants to waste money. Life presents us with choices that have-to be weighed and prioritized. Let’s give CBA it a try. Here are the general steps:
Step 1. Make a Cost List: This will need to be an exhaustive list of costs including purchase price, usage, and maintenance
Step 2. Make a Benefit List: This will be a list of benefits that should include things both tangible and intangible (typically the benefits are assigned dollar values)
Step 3. Do the Analysis: This can be simple math Or alternative methods
Now that we have a framework, it’s time to focus and “Think Air Purifiers”. Are air purifiers worth buying? Let's find out.
A 5-Year "Are Air Purifiers Worth It" Cost-Benefit Analysis
Given that indoor air quality is important, many people have entertained the question: Are air purifiers worth buying? Wrapped up in this question are several related other questions about air filters in general such as activated carbon filters and HEPA filters. Do filters work? Is cleaner air possible? Is simply opening windows a viable alternative? Do air purifiers work like we are told? Is it possible to evaluate a home air system? These are all valid questions. Although we may not be able to address all of them in detail in the context of a CBA, we will do our best to balance a lot of information about science with practical guidance.
Step 1: Determining the "Air Purifier Worth Buying" Cost Inputs
Cost of Purchase Input
So, how do we determine the purchase cost of an air purifier when there is such a broad range of prices in the market? Well, borrowing from an old idiom which states “You Get What You Pay For” there is an implication that the cost of something is driven by its quality especially given that cheap things are generally low quality. Hence, to settle on a cost input our CBA leverages two notable industry manufacturers with different technology methods for air purification, both of whom are in the business of creating the best air purifier value proposition.
For HEPA Filter and Activated Carbon Filter Air Purifier Technology let’s use Austin Air. Founded in 1990, Austin Air machines are universally regarded as "reliable", "economical" and "well-built". Austin Air's Buffalo, NY facility is one of the largest air purifier factories in North America. These machines are made in the USA, consistently highly rated, and low maintenance. Under normal use, the combination HEPA Filter/Activated Carbon Filter is replaced every 5 years. Their lower tier model named “HealthMate” retails at $594.99.
Austin Air Purifier "Worth It" Street Credibility:
- Clinical Trial 2001 by Cincinnati Children’s Hospital that tested reduction in asthma symptoms
- Clinical Trial 2009 by Johns Hopkins which measured the effectiveness of reduction in Nitrogen Dioxide NO2 present in homes with gas stoves
- Testing in 2015 by University of Washington for reduction in ammonia from the home
For Filterless Air Purifier Technology, let’s use Airocide. Founded in 2007, Airocide products have a fan that draws the air from your home into the unit. The home air is slowly pushed across hollow glass tubes coated with what is called a catalyst that facilitates the chemical process known as Photocatalytic Oxidation. It is safe, efficient, and has been proven to produce no harmful by-products. This is the same process that NASA used as a VOC (Volatile Organic Compound) air purifier on the International Space Station. Airocide has now leveraged this technology to purify air in our own homes here on Earth. The APS-300 model (which I own and use every day in my own home) costs $999.00.
Airocide Air Purifier "Worth It" Street Credibility:
- Technology designed by NASA for use in space
- Technology approved by FDA for use as a class II medical device
If we split the difference between the two units, we arrive at a cost of approximately $800, which is a suitable input to our analysis. For emphasis, we know these air purifiers are effective and backed by scientific studies. We know we are getting what we pay for, which is important when we later consider the benefits. In order to list benefits, we need some assurance that they are not just marketing hype.
Cost of Use Input
To determine electricity cost per month:
Machine Wattage * rate/kilowatt hour x Hours/Day x 30 x 0.001 —— Monthly Cost
Wattage = the wattage draw of each machine (can be found on each model's specification sheet)
Charge/kilowatt hour = Can be found on your electric bill
Hours/Day = How long the unit runs per day (24 max)
Days/Month = 30 average
Multiply by 0.001 = Converts from watts to kilowatts
If you have a 135-Watt (An Austin HealthMate on high speed) unit that costs 12 cents per killowatt hour and you ran 24/7 then:
X = 135 Y = .12 Z = (24*30*.001) or .72
X * Y * Z = (135 * .12 * .72) = $11.66 per month or ~$140 a year
If you have a 60-Watt (An Airocide APS-300 on high speed) unit that costs 12 cents per killowatt hour and you ran 24/7 then:
X = 60 Y = .12 Z = (24*30*.001) or .72
X * Y * Z = (60 * .12 * .72) = $5.18 per month or ~$62 a year
Note: Given Z assumes non-stop use or 24/7, then we are calculating a worst-case bill.
Once again splitting the difference between the usage costs we arrive at approximately $100 a year, another quality cost input for our analysis.
Cost of Maintenance Input
The Austin HealthMate Filtration System lasts on average 5 years and the replacement cost is $240; we have $240/5 = $48 per year.
The Airocide cartridge needs to be replaced every 15 months and costs $179. In 60 months or 5 years that requires 4 replacements or 4 * $179 = $716. Now per year that equals $716/5 or $143 per year.
Once again splitting the difference between the maintenance costs and conservatively rounding up we have approximately $100 a year, the final cost input for our analysis.
To summarize we have:
- $800 purchase
- $100 a year usage or $500 for 5 years
- $100 a year maintenance or $500 for 5 years
Our 5 Year Cost = $1800 or $360 per year
Step 2: Determining the "Air Purifier Worth Buying" Benefits
In general, benefits can be categorized as follows:
- Medical expenditure savings
- Productivity or other gains
- Psychological benefits of good health, feeling better, happiness
The Human Capital approach assumes that we are a worker whose value equals our earnings. A loss of productivity is a loss of earnings. If we lost 5 days at work due to an illness, we can assign that to 5 days of wages. The issue with this approach is that value is directly related to wages which is ultimately a measure of livelihood rather than the value of living a satisfying life.
On the other hand, the WTP or Willingness-To-Pay approach considers disposable income and length and quality of life. Hence, if there is an intervention (an air purifier) whose benefits can be measured, then the WTP approach is defined by how much money an individual will pay to obtain it. But how can WTP be measured?
Well, the free market places a lower bound on this by establishing how much people are willing to pay for products. Given our working example, the Austin HealthMate air purifier cost is $594.99. That is the cost associated with purchasing a product whose benefits are supported by scientific data. Of course, there are other products that cost less, and so each would demand their own separate CBA. Our analysis has made certain assumptions that people are willing to pay more for what is clearly higher quality. Furthermore, we introduced an alternative technology with a cost of $999.00 in order demonstrate additional value the market places on NASA related designs and FDA approval.
We suggested using an average value or a middle ground between these costs in order to facilitate arriving at inputs for our CBA. If one chose the Human Capital approach then actual values could be computed. In essence, the CBA would reveal that air purifiers are worth it if the benefit value exceeded the cost of $360 per year. This could easily be defended based purely on math. For example, if a person lost 5 days wages per year valued at $100 a day due to illness, this equals $500 a year. However, one would then need to prove that sickness was due to environmental conditions that could be remedied by an air purifier.
However, we prefer to use the WTP approach as understood in the context of consumer discrete choice and preferences. Air purifiers are useful tools to address specific health-related concerns about cleaner air such as:
Allergies, asthma, bacteria and viruses (like Covid-19), better sleep, chemicals, dust, multiple chemical sensitivities, VOCs (Volatile Organic Compounds) mold, odor, pollen, pet dander, smoke.
Given the above, what value do you assign to something that mitigates specific health concerns? How much is that worth to you? In this context, is an air purifier worth buying? If you suffer from allergies, putting the cost of OTC or even Rx pharmacy products aside, what value do you attach to the relief of your symptoms? Using our derived cost of $360 a year from Step 1, is allergy relief worth $1 a day even though medication might be less direct cost? Intangible benefits (like air purification vs. medication) are important considerations. An additional benefit of air purification is the many to one ratio. Given a single air purifier can tackle a list of air quality concerns, the side-benefits would be having something you purchase for your allergies that also happens to kill bacteria and viruses that could harm you and that conveniently removes dog odors or cat dander. What is the value of a good night's sleep?
Step 3: The "Air Purifier Worth Buying" Analysis and Conclusion
Are air purifiers worth it? Is an air purifier worth buying? Are they a waste of money? Now that you know the costs associated with quality machines available for purchase it's time to do your own CBA. The hard part is done. You have been presented with two quality machines to choose from along with a framework for analyzing the benefits they provide in your own life.
To Learn More visit our "Best Air Purifier" collections at Think Air Purifiers Home
If you would like to know more about Austin or Airocide:
- Cost Benefit Analysis for Health, Zweifel, P and Telser, H, University of Zurich, 2009
- Part IV: Benefit-Cost Analysis, Lane, Soyemi, CDC Division for Heart Disease and Stroke Prevention, 2017