Most air purifiers mention their Clean Air Delivery Rate (CADR), which is a measure of the unit’s airflow times the filtration efficiency in air purifiers. As two variables are used to calculate the CADR, an increase in one can offset a decrease in the other—but still result in an higher CADR rate. The CADR is meant to be impartial and is advertised as the the best way to compare air purifiers. However, it can be misleading. Why is CADR a misleading comparison for air purifiers? The CADR is biased towards air purifiers that circulate a higher rate of semi-clean air, rather than air purifiers that can clean the air well, but circulate air at a lower rate. Greater filtration efficiency can slow a units airflow, allowing for air purifiers with lower efficiency, but faster air circulation to have a higher CADR. While airflow rate is important to consider when researching air purifiers, higher filtration efficiency will give you the greatest benefit with more purified air. The Problem with CADR Testing

This may be caused by the test used to calculate CADR. In this test, a unit is placed in an enclosed room that is then filled with airborne contaminants. After running the unit for 20 minutes, the air quality is then tested and the CADR is calculated. This is a relatively small amount of time for most air purifiers, as many higher-end air purifiers require at least an hour to circulate air and improve air quality, especially if the filtration efficiency is high. Therefore, the air purifiers that circulate more air tend to have higher CADR, despite the fact they removed a smaller amount of contaminants. In order to score well on this test, many manufactures have designed their air purifiers to circulate a lot of air quickly, filtering only the larger contaminants. This can mean companies who compete based on their CADR usually do not have other filter offerings other than standard HEPA filtration. Adding filter options with carbon, odor removal or silver-ion technology will reduce their air purifiers’ CADR score, making them less competitive with other lower-end units.

Alen Air Purifiers and CADR CADR also fails to indicate a product's ability to capture and remove bad odors, bacteria, or volatile organic compounds (VOCs). grasscity air purifierAlen Air Purifiers successfully removes these contaminants from your indoor air with versatile filter options, which the CADR does not take into account. therapure air purifier 230mFor this reason, Alen Air Purifiers are not rated by the CADR system. oreck airinstinct 75 air purifierWe believe a higher filtration efficiency is more important than a higher airflow rate, giving you the greatest benefit from our air purifiers. Our purpose is to help our customers Live Better by removing an effective amount of airborne particles and contaminants from your indoor air, not to receive a higher CADR.

Are you interested in learning more about Alen Air Purifiers or CADR? Visit our Product Advisor or call an Alen Air Quality Specialist 800-630-2396 to learn more.Efficient HEPA Air Filter... though somewhat noisy on highI bought the unit four months ago and for the first three months it seemed to be running great and making enough of a differenceColor: Black|Worth the moneyColor: Hm450-Black|Should be a 10 starso far so goodGreat air purifierFilter for my art studio?Air filtering: 5. Fan Motor: 1Pleasantly SurprisedNo More Litter Box Odors←Previous... See all 94 answered questions Customers also viewed these itemsAustin Air HealthMate Jr PLUS Air Cleaner, White49Austin Air HealthMate - Black122Rabbit Air BioGS 2.0 Ultra Quiet HEPA Air Purifier (SPA-625A)109Healthmate HM-400 HEPA Air Filter Purifier - Sandstone122Need customer service? Germ Guardian AC4900 Clean Series 22 Inch True HEPA with UV-C Air Purifier Buy Used from $74.20 in Open-Box & Used » Additional Warranty Options Available

Indoor allergens, unpleasant odors, and unhealthy airborne germs can all contribute to poor air quality in your home. The Germ Guardian AC4900 Air Purifier helps eliminate these problems. This HEPA UV air purifier scrubs air clean with a 3-stage filtration system that consists of particle HEPA filtration, charcoal filtration for odors, and UV-C light treatment to neutralize germs. This tower-style model is ideal for treating rooms up to 183 square feet. It's great for a bedroom, living room, or den. The AC4900 Air Purifier by Germ Guardian cleans air thoroughly with a 3-stage filtration system that removes allergen particles, odors, and even airborne germs. During the first filtration stage, room air passes through an activated charcoal pre-filter, which captures large dust particles, lint, and pet hair. Absorbent charcoal material in this filter also works hard to absorb unpleasant household odors stemming from pets, cooking, and chemicals. Next, air passes through a true HEPA filter.

This filter is designed to capture 99.97% of dust and allergens measuring as small as 0.3 microns. This includes the most common indoor allergens like dust, pollen, mold, smoke particles, and pet dander. Finally, air is treated with UV-C, or ultraviolet germicidal, light, to kill airborne bacteria and viruses including rhinovirus, E. coli, and streptococcus. Clean, purified air is then released into your space through the front of the unit. The Germ Guardian AC4900 Air Purifier has a number of convenience features designed to simplify daily operation. Choose from 3 purification speeds to suit your preference. The lowest speed is virtually silent and ideal for the overnight hours. A filter replacement indicator lets you know precisely when it's time to replace the filter, so you can ensure optimal air cleaning. Plus, a UV-C light indicator notifies you when you need to replace the UV-C light bulb. Slim Tower Design - A slim tower-style design saves space and looks great. CADR Rating - The AC4900 is ideal for cleaning the air in spaces up to 183 square feet.

It has received a CADR score of 118+ in dust removal, pollen removal, and tobacco smoke removal. UV-C On/Off Control - Turn off UV-C light treatment when you don't need it with the independent light control. Energy Star-Qualified - For eco-friendly and budget-friendly operation. Breathe cleaner, healthier air indoors and enjoy convenient operation with the Germ Guardian AC4900 Air Purifier. Filter Replacement Indicator - This indicator light lets you know when it's time to replace the combination filter. Slim Tower Design - Tuck this 22-inch tower unit in the corner of a room to save space while still enjoying the benefits of cleaner air. Keep Up With Filter Replacements - For optimal operation, the combination HEPA/charcoal filter should be replaced about every 6 months. Manufacturer's Literature • Germ Guardian AC4900 Owner's Manual Germ Guardian AC4900 Air Purifier Ideal for allergy and asthma sufferers and fighting household odors Filtration SystemPre-FilterHEPA Filter, True Medical Grade HEPACarbon Filter

HEPA Filter TypeTrue Medical Grade HEPA Type of Germ TreatmentUV-C Light View All Germ Guardian AC4900 Clean Series 22 Inch True HEPA with UV-C Air Purifier Reviews Displaying reviews 1-2Really cleans the air!!! ProsAffordableAttractive DesignUser friendlyConsLoudBest UsesAnywherePrimary use:Personal(2 of 2 customers found this review helpful)As advertised and Shipped FAST! ProsAffordableAttractive DesignConsLoudBest UsesAsthma ControlBedroomSmaller roomsPrimary use:PersonalDisplaying reviews 1-2Back to top Germ Guardian True HEPA Replacement Filter B (FLT4825) Germ Guardian LB4000 UV-C Replacement Bulb for Air Purifiers Aprilaire 4897 Conversion Frame Winix Size 17 Replacement Filter Set (113050) Winix Size 25 Replacement Filter Set (113250) Friedrich Replacement Nylon Pre-filter Alen T300/T100 Replacement HEPA-Fresh Filter - Set of 2 (TF30) Oransi v-hepa Replacement HEPA Filter (RF2311) Coway AP-1012GH Air Purifier Replacement HEPA Filter