Tuesday, September 21, 2021

Air Purifiers: 6 Steps Before You Buy

Life is good for the air purification industry. With studies indicating that the rising rates of respiratory ailments are the result of high levels of indoor air pollution found in American homes, residential air cleaning systems have been selling like hotcakes.

But take a moment before you join the horde of consumers rushing out to a big box retailer for the latest in air scrubbing technology. Finding a quality air purifier can be tricky, and a bad one might pollute your air more than clean it. But with a little preparation, you can up your chances of finding a system that’ll do the job. Here are some steps homeowners should take prior to purchasing a home air purifier.

1. Determine Your Needs

Many types of air purifiers fill the market place, and they operate in different ways and target different pollutants. Finding one that fits your needs requires you have a clear understanding of what those needs are. A person suffering from mild allergies has a very different set of needs from someone with severe asthma or autoimmune deficiencies. Clarifying your needs can help you avoid wasting money on a system that does too little or too much. Furthermore, upon reflection, many of you might find that you don’t really need a purifier at all.

2. Stopping Indoor Air Pollution at its Source

You wouldn’t address a mosquito problem by lighting citronella candles while a plastic kiddie pool full of fetid water sits in your backyard. Similarly when dealing with air quality it’s best to address a problem at its point of origin.

Pollutants come from a variety of sources within a typical residence and preventing their occurrence requires a comprehensive multi-step approach including:

  • Cleaning – Vacuuming rugs, dusting furniture, addressing mold and mildew build up, and cleaning out your HVAC systems air ducts.
  • Dehumidification – Installing a dehumidifier to address high humidity levels which often exacerbate pollutant levels.
  • Maintenance – Ensuring that stoves, dryers and your HVAC system are all in working order.
  • Ventilation – When possible, incorporating natural or mechanical ventilation to help reduce levels of indoor air pollutants.

Many times, addressing these problems will fix your air quality problems and eliminate the need for an air purifier altogether.

3. Decide Between a Room or Whole House Purifier

Probably the most important decision you will make regarding an air purifier purchase is whether you want a central purifier that cleans your whole home, or a room only purifier. Each type has distinct advantages:

Room Purifiers

These are the ones you’ll see in Best Buy, Sharper Image or other electronic stores. They’re generally free standing devices that don’t require professional installation and they range from under $200, to over $1000. Many manufacturers put them out and they can use a wide variety of processes to clean the air.

As you’d expect, these systems are ideal for maintaining clean air in a single room. If you’re suffering from allergies that interfere with your sleep then a single air purifier placed in the bedroom might be all you need.

Also keep in mind that most room purifiers are portable, meaning that you can move them around the house and thus avoid having to buy multiple systems.

Here are some pros and cons of room only purifiers


  • Often cheaper than whole house alternatives
  • Generally don’t require professional installation
  • Don’t require a forced-air HVAC system for operation
  • Portable


  • Take up space in living area
  • Often noisy
  • Generally don’t work as well at lower(and quieter) speed settings
  • Occasionally produce smells

Whole House

These systems usually hook into your forced air HVAC system, using its fans and ducts to draw air in to the purification unit. Most systems are installed into your HVAC ducting.

The price and complexity of whole house purifiers range from cheap, doityourself filters that simply replace the standard furnace filter; to expensive systems requiring professional installation and costing hundreds. Some of the priciest systems are freestanding self-powered units that rely upon ducting but operate independent of the HVAC system.


  • Quieter than room only systems
  • Doesn’t take up space in your living area
  • Ideally situated, as HVAC ducting is often a prime source of air pollutants, mold, dust etc


  • Often expensive
  • Critics claim that whole house systems don’t target specific rooms as well as a room air purifier
  • Generally require a forced air system
  • Usually don’t work when HVAC is off

4. Learn the Different Methods of Purification

Air purifiers can use many processes in their operation, many of which target certain pollutants while missing others. Some excel at getting rid of particulates such as dust and pollen but miss gaseous pollutants such as carbon monoxide. Others only target 室內空氣質素測試 viruses or bacteria. And some don’t really target anything at all. i.e. some don’t work!

Common types include:

Media/HEPA Filters

These systems trap particulate matter through the use of physical filters. The majority of legitimate purification systems incorporate some kind of media filter technology. The most effective of these are HEPA or High Efficiency Particulate Absorbing filters which are so effective in cleaning the air of particulate matter that they’re used in hospitals and other facilities that depend on sterile air.


  • Excellent at catching particulate pollutants
  • Many of the top performing purifiers are of this type
  • Require little maintenance
  • Often increase in effectiveness as they are used


  • The more effective filters block airflow and thus can reduce efficiency of HVAC systems
  • Replacing filters can be pricey
  • Filters that incorporate an electrostatic charge will quickly lose efficiency
  • Media filters can be hotbeds for bacteria


These purifiers pump ions into the air. The ions transfer their charges to airborne particles causing them to attach to walls or other surfaces and thus taking them out of the air. The process might sound bogus but it actually does work. Unfortunately it also has the side effect of creating ozone, a toxic gas that can exacerbate asthma and which also happens to be the main component of smog.


  • Quiet
  • Often Effective
  • Generally more affordable to maintain than HEPA systems. (No filters to replace)


  • Produces ozone
  • Ionization results in pollutants clinging to home surfaces, which can eventually lead to a blackening of those areas.

UV Lamps

These purification systems consist of UV lamps, which work by irradiating germs with lethal doses of ultra-violet radiation. They are designed solely to kill germs however and thus should only be used in addition to a filter system.

Warning: While all UV lamps generate ozone as a bi-product of their cleaning process, some are designed specifically to generate ozone. These should be avoided.


  • Effective in killing biological contaminants
  • Affordable and require little maintenance


  • Only kill germs
  • May produce ozone which assists in destroying viruses and bacteria but which can also prove harmful to humans
  • Whole house UV lamp systems require professional installation as improper installation can result in damage to eyesight

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