Arvell Moore
Texas, USA
updated 8/06/2007 
The air purifiers in this report have been tested in person by Arvell Moore experts. Consideration was given to air cleaning efficiency, pressure drop, how frequently maintenance is required, ions, ozone output and price. For those of you not familiar, ozone smell is that smell the copier at work makes when you've been running lots of copies. So not only is producing ozone bad for the environment, but it generates a scent that can linger in your home.

An ionizer can be just as bad for you. Ionizers like the Sharper Image's Ionic Breeze have great filtration results, but what a lot of people don't know is that those collection plates that are supposed to attract those ionized particles sometimes don't. If you don't take the plates out to clean them every week, or if you've had the unit for awhile and it loses efficiency, those particles will still be ionized. Instead of sticking to the plate, though, they stick to the walls of your home, your tabletops, counter tops, and the EPA says they stick to the walls of your lungs, too.

We performed two tests on each machine, the first being a simple particle count to determine how many particles the systems truly eliminate and the second being a pressure drop test to determine how much air flow we lost while using the machine. High filtration is great, but if we’re losing air flow because of that filter your A/C is not going to cool down a home.

A lot of systems claim to have a 99.7% filtration rate or higher, but what we found is that a lot of these claims don't take the unit's housing into account. A poorly constructed unit will allow for air leaks at points all around the housing. No matter how clean your filter makes the air that passes through it, it can't filter what doesn't pass through the filter! So we decided to figure out which one really is the best. Which unit can deliver the cleanest air available into my home without costing an arm and a leg to run?

Below are my recommendations and reviews
for air cleaners that actually work.. and those that don't.

Air Cleaners	Notes	Efficiency	Price
True Blue Fiberglass Filter	Will only filter out large plumes of dust (what makes it turn grey eventually); no apparent particle filtration. No restriction in air flow. Replacement needed monthly. More	0%	$1
3M 1250 "Purple"	Minimal filtration, slightly restricted airflow. Pressure drop at .21". Used to advertise as a MERV 12, though this claim has been removed. Replacement needed every three months. More	31%	$17
Honeywell F200 E	Electrostatic media filter. Loses efficiency the more you use it. They report the filter needs to be replaced every six months. Pressure drop at .35". Honestly, for it's filtration rate you'd be better off with the 3M Filtrete. More	24%	$
Honeywell F300 E	Ionizer. You could smell the ozone pretty  bad when it was switched on. There's a delay when it's switched on, and all the gross particles that have rested and collected there are blown out when it's switched on. This unit must be plugged into an outlet. A ridiculous amount of maintenance each month is needed on this thing. We also observed sparks. Pressure drop isn't bad at .25". More	65%	$$
Trane Clean Effects	Ionizer. This one and the Honeywell F300 E had the worst ozone smells of all the ones tested. Incredibly difficult to clean this one out, which needs to be done every two months. Pressure drop at .35". After two weeks, efficiency on this model dropped to a terrifying 70%. More	94%	$$$
Lennox PureAir	Uses a UV light to get rid of odors, so it produces a decent amount of ozone. Has one of the worst pressure drops of everything we tested -- .40". Filters only need changing once twice a year, though. More	75%	$$$$
Carrier Infinity	Another ionizer with an electrostatic media filter. The ozone smell wasn't as bad as the Honeywell 300F or Trane CleanEffects, but it was definitely noticeable. Overall an alright system. Pressure drop was average at .29". More	78%	$$$$
Broan NuTone Guardian	A bypass system, and frankly, a waste of money. Sure, it filtered out 80% of the particles that went through it, but the fan only blows at 270cfm. The average household fan blows at 1000cfm at the least. So only 20% of the air going into your home is being cleaned! It's a big waster of both money and energy. More	20%*	$$$$
Aprilaire 5000	A decent machine for it's price. It's got a pretty good pressure drop of .27" and pretty good filtration. Another ozone producer, but again not near as bad as the Honeywell F300 E or the Trane CleanEffects was. One thing we found is that it doesn't come in different sizes. You would use the same machine for a 3 ton system as you would for a 5 ton system which would, of course, lower the filtration rate and increase the pressure drop. So keep your system size in mind when shopping for this product. More	74%	$$
Honeywell Enviracaire Elite	Another bypass machine, this one operating at an even lower cfm of 250. It did show better filtration than the Broan-Nutone Guardian though, and at a lower price. So if your heart's set on a bypass system, this is probably your best bet. More	24%*	$$$
Envirosept Electronic Air Cleaner	I would rank this as the worst machine we tested. Not only was the filtration rate even less than that of a basic 3M Filtrate filter, but it produces large amounts of ozone smell and sparks to boot. The pressure drop level is also abysmal at .42", making it the most inefficient of any machine we tested. More	7%	$$
IQAir Perfect 16	This is hands down the best unit we tested. Try as we might, we couldn't find a thing to complain about it. The filtration rate is amazing, and the air flow was better than just about anything we tested at a .11" pressure drop. They don't use an ionizer, so there's no ozone. And the filters only have to be changed once every three years. And it's the only whole house cleaner whose price includes installation. This is Arvell Moore's #1 pick for a great whole-house air cleaner! More	97%	$$$$**