Air Purifier Evaluator

Comparing / Evaluating a Home Air Purifier

When most people shop for a home air purification, (probably what you are doing right now) they look to the internet for advice. When I looked today out of the 20 top organic results under the search “home air purifier” 11 of the results contain lists of that articles favorite air purifier. Not surprising is the fact that if a visitor who visits that page and then buys an air purifier suggested, the website that created the list gets paid a fee. 

Now that does not mean that these 11 listing pages are bad or un helpful. But I can tell you many times where a product appears on the list is directly corelated with how much the listing page gets paid. The more an air purifier maker is willing to pay to be #1 on the list of top 10 air purifiers the more likely they are going to be #1. Now, that is not true of every “best air purifier” web page, but keep it in mind as you shop. I have asked to have LakeAir products considered for these lists. I have been told my affiliate submittal would be considered, and as long there was sufficient profit involved I would be in the next list published.

That bring us to the 9 brand websites that made the top 20 results. These brand air purifiers are made by large companies with huge budgets for SEO. They are VERY good at making websites. This ability to make a good website has nothing to do with whether or not they make good air purifiers. The products featured all look very similar. They are designed to meet the current design fad. They are all plastic in construction and have many gadgets to make them to make them pretty neat. But do they clean the air? Yes they do all clean the air, but for how long and how well? Now if you have done your home work and research you should be fine with your choice. But, how well have you done your research? Is it even possible to really compare air purifiers with the data presented by the manufacturer?

Dissecting the Information ~ What Nuggets of information we need

Some air purifier manufactures provide a lot of useful information. These are the exception. Most manufactures are very vague with there product specifications.  I suppose this could be because they feel you are not smart enough to understand technical jargon. In this next section we will look at a few manufacture  adds and we will look at how to take the information they provide.

An Image of the product

Advertisers like to show big images so you can imagine how happy you will be with their product in your home.  Now the image shown to the right  is from a webpage Google ranked in the top 5  for the search “home air purifier”. There is nothing wrong with the photo, it displays the product and illustrates the way the unit is advertised to work. Some images are misleading in how much a product will do. Let the real specifications be the number 1 determining factor not a how pretty their photography is. I give the picture an “A” after looking at the spec’s. The air purifier, not so much. 

Common type of image used by air purifier advertisers

Air Changes per Hour

The most helpful information you can get out of a products specification is “Air Changes per Hour”. I looked for 15 minutes to find any specification having to do with air purification capacity for this unit.  There were 2 sets of speciation’s listed for this product, and they are shown  to the right. The specification told me how well the unit would clean but not how much of an area it would clean.

The second set of specifications did little more to help me figure out how much space the product would clean how fast. The information listed described the size of the product and again showed me it was a truly good looking unit.

30 minutes into my search I finally found a 3rd party review that had unearthed some real useful information. It turns out this unit will actually produce 87 liters of air/ second. Sound like a lot, but after the math is all said and done it turned out that this air purifier has a maximum air flow of 184.34 Cubic feet per minute. So what do we do with this hard to find information?

Specifications as displayed on a popular air purifiers website

Turning CFM into the information I need CADR

Determining the CADR is an easy task. If the CADR is not published but you know 2 things you can extract the air purifiers CADR. We need to multiply the air flow that is usually given in CFM (cubic feet per minute) Some manufactures may report air flow in the metric formula M3H (cubic meters per hour) you can convert m3h to cfm with this conversion calculator. I suspect in most cases manufacturers  use the metric form because that is what they use in there product development. However in some cases other forms of measure are used to be vague or to appear to be more impressive.

The other key element to finding  the CADR is the units filter efficiency. This number is likely to be in the product specifications. Air Purifiers with True HEPA filters will have an efficiency of 99.97. Other common reported efficiency values are 99, 97, 95 percent. Whatever the air purifier’s efficiency is, you multiply that number in this case 99.97 times the units CFM in this case 184.34 (0.9997 x 184.34 = 184 ish)

CADR (clean air delivery rate)

Now The CADR in itself does not really tell us how well this product will clean a large area as the product’s great video’s imply.  To determine how well it cleans, we have to consider the size of the space and what our goal of air cleaning is.

The air purifier above said it was good for large space. For the sake of our exercise lets imagine “our large space” is 30 x 20 x 8 

  1. Multiply Room L x W x H = Volume (4800)
  2. Volume / 60 = 1 ACH (80)
  3. CADR / 1 ACH = Effective ACH 

 We determined the effective ACH  for the mystery air purifier is 2.30 . We did this  by taking  the air purifiers CADR (184) and divide it by the 80 (The amount of air needed to clean the air once in a hour) and we find that the air purifier in question will clean the air 2.30 times in an hour. 

Air Cleaning Standards

In the United States of America the association that sets the standards for  indoor ventilation, heating, air conditioning, air purification (all things having to do with air flow) is ASHRAE

ASHRAE has set the standard for good air purification in home at a rate of 4-6 Air changes per hour. This is widely accepted in all states and many other countries. There are other groups who set suggested standards for other places. On our website page “air changes per hour” we have cataloged many suggested room air change requirements. These are all suggested levels and you should check with local authorities for your local requirements.  

Samples of air cleaning standards

  • General home use  — 4-6 ACH
  • Kitchens                  —  6 ACH
  • Cigarette Smoking  — 10 ACH
  • Cigar Smoking 14  — 14 ACH 

These samples are for residential areas and do not apply to commercial areas. As to the smoking recommendations, the suggested standard are for 1 smoker in a closed room set aside from the household living areas.

Evaluating Air Purifiers by Clean Air Delivery

In this section we will finally evaluated the air purifiers based on its specifications and the needs of our families and homes. To recap where we are; the air purifier we are evaluating can deliver CADR of  184 CFM. we know that the space we want to use it in has a volume of 4800 Cubic feet. Doing our math we found that it will take 80 CFM to clean the air once an hour. To find out if the air purifier we are evaluating will be sufficient, we divide the products CADR 184 by our 1ACH number of 80. The result is 2.3 air changes per hour. The standard set by ASHRAE is at least 4 air changes per hour. So according to all the math and the accepted standards this mystery air purifier will not clean our large space.

WOW! that was a lot of math. No one should be expected todo all that math. 

We have created an evaluation tool to do all this work for you.  In this tool you can enter your room dimensions and it will do the math in figuring out room volume for you. You can also enter the CADR of an air purifier you are considering buying.  If that’s not provided you can enter the  units out put in CFM and the units filter efficiency. After you enter  the information the Evaluations tool will tell you if you air purifiers information you entered is good for one of 4 uses.

  • General Home Use
  • Kitchen Use
  • Cigarette Smoking
  • Cigar smoking

The evaluation tool will also tell you how big of an area your product inputted will handle. (this is based on an average ceiling height of 8 feet tall.


More Evaluating Tips

At LakeAir we take home air purifiers very seriously. We know that our home air purifiers are very good, but we also know that they are not what every person is looking for. It is our goal to inform and educate the customer. In the rest of this page we are going to point out some things that will hopefully help you make the best clean air choices for your home and family.

What's Really Important?

Being we are talking about air purifiers i am lead to believe that cleaning the air and cleaning it well is most important. The evaluating tool above shows you if a unit (based on manufacturers specs) will do a good job cleaning the air in a space of your choosing. According to the 4 most important things to consider when buying an air purifiers are.

  1. How well does it clean the Air
  2. How large of an area will it cover
  3. Operating Noise
  4. Price
We at LakeAir would agree with this list of priorities. In the next section we would like to epound on each topic and hopefully shed a little more light  onto these topics.

Evaluate (How well does your air purifier of choice, clean the air)

Lets face it, an air purifier is a box with a filter and a fan. That is what all air purifiers boil down to. So in this evaluation we will look at filters. Everyday companies are coming up with new filters. One filter for nitrous oxide, another specially for formaldehyde. While all of these specializations are nice, what we really need are products that remove a lot of bad stuff from the air. LakeAir is an old fashion company, one of my competitors said I haven’t updated the website since the 90’s “Ouch!” We believe in core values. Core values are still found in ASHRAE’s recommendations. When this leader in clean air standards changes its tune on air filtration, so will we.

Does your air purifier use tested (widely accepted) filter technology? If your air purifier use a good quality HEPA filter you are on the right track. We get questions from customers about competitor filters that off-gas odors.  They want to be sure are filters are made in the USA. I am not certain that eliminates the possibility of off-gassing but it does seem to make a difference.  

Electrostatic, MERV and Carbon filtration are also time tested filtration methods. None of these are as good at removing particles from the air as a HEPA filter but there is quality available in the filtration types as well.  

The filters in your air purifier should be large and robust. a small filter will fill up with pollutants fast and the air purifiers performance will nose dive in a hurry. Look for large well built filters.

Evaluate (How large of an Area does your air purifier clean)

Air Purifier manufacturers love to claim large area coverage. Its not uncommon for a seller to claim 1400 square foot coverage, but at how many air changes per hour? The real experts (ASHRAE)  will tell you 4 air changes per hour is the minimum standard for a normal home. Good filtration in a home is 6 air changes per hour. So that 1400 square foot unit better have a CADR of 1120 or its not making the grade. Look closer at the product claims. make sur you are evaluating at least 4 air changes per hour and better yet 6.

Evaluating (How loud is your air purifier)

I will tell you he biggest challenge as a air purifier designer I face is making n air purifier work well and do it quietly. We need to squeeze a lot of air through a tiny hole and that my friends make a bunch of noise. The best way to have an air purifier perform well  with little noise is to oversize the blowers for the job. That’s how we are able to get great air purification with less noise from our MAX Guard Line. If you turn them all the way up they are noisy but they are so powerful you don’t need to run them on full to get amazing air purification. The MAX Guard has a sound rating from 40-70 dB (decibel) How loud is that?  The next section speaks to comparisons of decibels and common everyday experiences.

How loud is a decible?

Sound is measured in decibels. The whole idea of decibels  was started as a way to measure how well or poorly a telegraph  or phone signal was transmitted. With refinement, a very accurate scale has been developed. The amount of sound generated by an air purifier is reported by decibels. This is the easiest way to measure the sound produced.  The abbreviation for decibels is dB.

Below we present a list of common occurrences to help you gauge just how loud a certain decibel reading is. 

  • 0 dB – The softest sound a person can hear with normal hearing 
  • 10 dB – Normal breathing 
  • 20 dB – Leaves rustling, a ticking watch
  • 30 dB – A whisper
  • 40 dB – Refrigerator hum, a quiet office
  • 50 dB – Moderate rainfall 
  • 60 dB – Normal conversation, dishwashers
  • 70 dB – Vacuum cleaners, traffic
  • 80 dB – Police car siren, a noisy restaurant 
  • 90 dB – Hairdryers, blenders, power tools
  • 100 dB – Motorcycles, hand dryers
  • 110 dB – Nightclubs, sporting events
  • 120 dB – Thunder, concerts, a jet plane taking off

An important thing to know is to loud of noise can damage your hearing. Your average exposure should be no louder than 70 dB (decibels) . NIOSH  (National Institute for Occupational Safety and Health) has set a level or 85 dB for no more than 8 hours a day for work places. LakeAir air purifiers use variable speed controls and can be set to well within safe and comfortable sound level. 

Decibel Chart as shown on MD-Hearing-Aid

Evaluating Cost (Does Your air purifier cost too much ?)

Evaluating the cost of an air purifier is really a complicated chore. In the end you will need to make the evaluation yourself. In this section we will try to give you a some information to help you decide how valuable your air purifiers is.

First off lets look at average prices of different house hold appliances

  • Refrigerators average cost in 2023            $1500.00 with models easily reaching $4000.
  • Ovens average cost in 2023                        $1150.00 with models reaching $3500 for some models installed
  • Televisions average cost in 2023               $1000.00 and as much as $4000
  • Air Conditioners Average cost in 2023      $7500.00 and as much as $22,000 depending on where you live.
  • Air Purifier Average Cost in 2023               $1150.00  and as much as $3700. for some deluxe models

These figures were found using simple google searches. We listed many of our sources below.  These results don’t reflect how cheaply you can buy any of these items if you search for deal. But they do provide a little scale. Air conditioning and refrigeration are more expensive, Televisions and Air purifiers cost a little less. These comparisons can help you decide just how much you should be spending. Use these along with the considerations below.


When evaluating the cost of a potential air purifier purchase the most important factor is performance. Through out this website we talk about performance of an air purifier. How much air a unit will clean and how well should be your first point in evaluating. However, if you can not afford a $1000.00 air purifier not amount of air purification is going to make the purchase make sense.


A products durability isn’t necessarily the number point to be considered in your evaluation, but it should be important. According to US Air Purifiers the average life span of an air purifier is 3-5 years. I would agree that is a good average. However I can tell you with certainty that LakeAir Air purifiers are built to last 15 or more years. We have models that have been in service for more than 30 years. Spending more money today for a product that will be around for more than 10 years has a value and you should consider durability of any product you buy.


Want is one thing, NEED is another. If you need an air purifier to help you live a healthy life, the importance and therefore budget should be larger than a product you just want. Need doe not add value to any product but it does increase its importance. So as you evaluate  your air purifier choices. don’t be afraid to expand your budget if you can find a product that has both performance and durability.


Gadgets are wonderful. They make us want a product more. Most gadgets however  shorten the life of a product. The more parts you add to ant product adds to the list of what can break. Air purifiers with monitors built into them will most likely fail sooner than one that does not. At this time sensors have a short life. According to EPA. GOV air sensors last one or two years. After that they can no longer be depended on. It is better to buy a good air purifier without a particle sensor and a particle sensor separately. The other gadgets in air purifiers are nice but they don’t make them work better. If this convenience is important to you, then you should give it extra weight. If you just need clean air put a little less weight to this aspect


The final and probably most important aspect to determining if a planned air purification purchase costs to much is whether it fits into your budget. Your budget is determined by the amount available money you have. You may decide the portion of your available funds to go to this purchase might be tempered by your need. But in the end if you cannot afford it, you shouldn’t buy it.

There are a couple of ways to possibly get the brand you want even if the checking account is a little short.

  • Purchase all or part of the air purifier using your HSA. 
  • Purchase a refurbish model
  • Purchase on installments (Any purchase on the LakeAir Website cab be bought in installment payments through PayPal)