Let's take a look at common home air purifier and air cleaner technologies:
HEPA Filters –
Stands for High Efficiency Particulate Arrestance. As indicated by its name, it only handles particulates. HEPA filters do nothing for odors and gases in the air. HEPA filters use a powerful fan to force the air through a very tight membrane filter to achieve high efficiency particulate filtration. They require expensive filters; they do not remove odors, gases, pesticides, viruses and many bacteria. Because the filter fibers are very small and tight, they cannot be used at the whole house level otherwise they would limit the airflow through your central heating or air conditioning and could damage your systems air handler. As a result, HEPA filters are sold as a standalone in room units only. This also means that to handle an entire home, you need multiple HEPA machines, making this VERY costly and inefficient. One of the best room HEPA air purifiers for particulate reduction is the IQ Air HealthPro, but even that only covers 320 square feet and prices start at $749. Imagine your cost to handle an entire 3000 square foot home! It makes our solution a complete bargain! Once again, odors and gases are unaffected. At best, a partial solution.
Ultraviolet Air Purifiers –
I sell two of the leading UV air purifiers on our website. BioZone Air Purifiers and Air Oasis Air Purifiers are both very good standalone air purifiers for handling biological contaminants, odors and gases. However, they do little on dust or airborne particles. Sure, the manufacturers claim that the ionizing properties will help remove some dust from the air; however, they simply cannot do enough on the dust to make a big difference for you, especially if dust is your main source of discomfort. And despite the claims of “covers up to 3000 square feet”, the small fans and resulting airflow are simply not sufficient to handle a large home. And they certainly won’t work through ceilings and floors. As a result, multiple units are required to handle an entire home.
Now here's the good news. If dust isn't your main concern and you want to eliminate pet or smoke odors, or kill pollen spores, mold spores, bacteria, viruses and germs. This Ultraviolet technology like BioZone and Air Oasis is excellent.
Using tons of marketing hype, Sharper Image sells the Ionic Breeze and brags about it having no fan. Simply put, air movement is REQUIRED to clean the air. At $400 each and no fan, you need 4-5 of these things to cover a medium sized home. Plus they are only minimally effective on removing dust. Once they get dirty, they lose effectiveness, thus requiring frequent cleaning. They do very little on the biological contaminants and do nothing for odors and gases. No wonder Consumer Reports was less than flattering in their discussion about this type of purifier. If you have one or more of these, Sharper Image has a return policy. See if it’s not too late to get your money back.
Electrostatic Precipitators –
Oreck makes this type of air purifier. Yep, the vacuum cleaner company who decided if they can clean carpets, they could clean air as well. Go figure. While they are on the right track by saying that you have to “Move air to clean it,” their units do nothing but collect airborne dust and large particles. They are only minimally effective on biological contaminants and again, do nothing for odors and gases. Like ionizers, once the collection trays get dirty, they lose their ability to attract and collect additional particles. Not only that, if the collection trays are dirty, these charged particles pass right through the Oreck and end up sticking to your walls, furniture, and even you. Having heard from countless smokers who have purchased the Oreck, their homes still smelled like smoke. Oh yeah, coverage is up to 500 square feet making multiple units a requirement once again.
Combination Air Purifiers –
Some companies have started combining a number of technologies in an attempt to handle the full spectrum of pollutants. While they cover a more complete group of pollutants, they are often VERY expensive to purchase AND more so to maintain. They often combine ionization, HEPA filters, sometimes UV, along with carbon filters to remove odors. Unfortunately because they are standalone machines, they are often noisy and cover only a small area making multiple machines necessary to handle an entire home. You can go this way and get pretty close to the full spectrum of coverage, but I wouldn’t recommend it due to the initial expense, ongoing filter costs and limited area of coverage.
Whole House Air Cleaners –
Some heating and air conditioning contractors will offer you a whole house air cleaner that needs to be installed into your furnace. They typically use a heated probe that simply burns the airborne dust as it passes through the air cleaner. Honeywell is one of those household names that you may be familiar with. While this type of unit may slightly reduce the dust in your home, again, biological contaminants are not affected, and odors and gases simply pass right through. An expensive option for SOME dust reduction.
Whole House HEPA Filters –
My mom spent about $2,000 on one of these. It required expensive ductwork reconfiguration, the filters are VERY expensive and they are only partially effective against particulates. Here's why. If you were to put a quality HEPA filter in line with your system, you would reduce the airflow so much that your system would grind to a halt. You need to pull a certain amount of air into the returns for your system to work well. The engineers "solved this problem" by creating a bypass system where they route about 30% of the airflow through the HEPA allowing 70% to flow through unfiltered. It assumes that after multiple passes, you will get most of the particulates. Sure, this allows for less airflow restriction, but it also allows 70% of the air to pass through unfiltered. An expensive and unacceptable option in my book.
A quick warning:
Most heating and air conditioning contractors offer air cleaners or whole house HEPA systems, but they are not qualified to advise you in this area. Just call a few and ask them about air cleaners. Most know the cost, how to install them and that they will reduce the dust levels in your home, but get more specific and they can't provide the answers.