GermGuardian AC4900CA Review

GermGuardian came on the air purifier market stage after the 2009 peak.

I expected them to falter along with so many latecomers, but they provided good value and supported their products fairly well.

GermGuardians are among the top selling purifiers at Amazon, competitive on price AND service.

So how to step up the ante, with so many variables at play and product price so sensitive ($100)?

Consumers feel they cannot afford an air cleaner, with the $100 price point forming a ceiling.

Aesthetic improvement, noise reduction, filter life, and overall cost to run - any one of these could be a deal killer.

But the latest result is the GermGuardian AC4900ca air purifier is selling well enough to garner 32 Amazon buyer reviews, averaging a strong 4.7 stars (most reviews are from Amazon Vine Participants, who get a free item in return for posting).

GG4900 has just two negative reviews, both mentioning strong initial odor issues.

4900 is a 22 inch tower with 3 fan speeds, dropping into a $100-true-HEPA niche populated with Honeywells and Whirlpools.

My big issue with this class of underpowered little "towers" is the tendency to under-install them in large rooms.

GermGuardian AC4900 is a "100 CADR" air cleaner, suited, in my opinion, for small rooms 100 sq. ft. and below.


AC4900 is marketed as having "100" CADR, "for small to medium rooms and CADR rated 100", but is NOT LISTED in the official tables.

There is NO CADR listing for any Guardian purifier.

Airflow in Cubic Feet per Minute (CFM) is also scarce.

I have seen "Tobbacco CADR 118" at trusted vendor, but not many others are carrying that figure.

Filter Train

Guardian 4900 uses just one, reasonably priced, single combination filter with multiple levels: HEPA, Pre-Filter, with a charcoal layer.

GermGuard asserts the filter has met True-HEPA standards (retains 99.97% of .3 microns which pass through the filter).

Every 6-8 months, depending on conditions, owners must procure a "filter B" (model FLT4825) replacement.

Guardian's charcoal filter layer assists the Photocat in reducing common household odors.

User reviews say "filter replacement is easy".

A filter replacement indicator, a green power light that turns red when the filter needs replacing, takes the guesswork out of filter life timing.

Of course, air cleaners in his price class are targeted toward first-time buyers, most owners will hurry to buy the replacement filter at the first flash of red.

Buyers should remember that HEPA filters are used up when BLOCKED, not when darkened.

I would run GGAC4900ac until airflow is 50% restricted before ordering the replacement filter.


Most buyers, including a majority of Amazon AC4900 reviewers, have no idea about PCO.

The explanation just floats right past them - "I like it, but can't explain how it works.".

UV-C light strikes the Titanium Dioxide (TiO2) film on the surface of a plate, usually Aluminum, causing some electrons to jump up one energy level, creating oxidants.

These oxidants, primarily superoxide and hydroxyl radicals, operate at the molecular level, eating odors, killing microbes, and oxidizing very fine particulate in the .1 micron size (very small particles ONLY).

What shoppers need to know about PCO is these oxidants do NOT persist (as ozone does).

Switch it off, in seconds the oxidizers die out.

The UV-C comes from a 5W bulb - not much power - scheduled for replacement every 6-8 months. amazon ad boy

Mercury lamp disposal is regulated by EPA, and replacement lamp buyers are supposed to send the old bulb back for EPA-approved disposal.

It is very important NOT to LOOK at a lit UV lamp.

And NOT to TOUCH the glass.

Children should NOT be left alone with a UV-C device.

AC4900's UV lamp does have it's own on/off switch.

GermGuardian AC4900 PCO has a good reputation as a normal household odor eater.


GermGuard 4900 is on the California Air Board's (CARB) approved air purifiers list (ozone less than 50 ppb).

And the ads for the replacement UV-C lamp say "produces no ozone."

A Philips head screwdriver is required to remove the aluminum shield to replace the UV-C bulb.

With three (3) fan speeds, CA4900ca is not too loud.

User reviews say they sleep on low speed, with a few saying "two."

There are a couple reviews complaining of new filter odor, both at break-in and filter replacement.

There are no remarks concerning persistent odors.

Yes, there is a UV nightlight on/off switch.

Warranty and Utility

How about the EPA Energy Star rating?

Burning 55 Watts on high, and using 118 as the Dust CADR number (quoted from, I get 2.145 CADR per Watt, near the lower edge, but yes, good enough for EPA.

Measuring 8.9 x 7.1 x 21.8 inches, GG AC4900 is small enough for most applications.

It weighs just 9.6 pounds, and can easily be moved.

AC4900ca does exhaust air at a leftward angle, making it require about 12 inches clearance from objects.

Corporate and Warranty

Guardian is located in Ohio:
Guardian Technologies LLC
26251 Bluestone Blvd.
Ohio 44132
"attention: Customer Service"

While websites selling the AC4900 say "3-year" Limited Warranty, the Guardian User Manual says "1-year."

I wouldn't bank on a big windfall on a warranty claim when the purchase was just $100, shipping costs hafta be at least $60, they will charge you for parts and labor, and there is some risk of loss/damage in post.


4900 review


small footprint
good for moderate odors


filter & lamp replacement costs, $90/yr?
weak CADR
small room size 100 sq. ft. - dorms and closets
filter outgassing three days with each filter buy
some sensitives object to filter outgassing

GermGuardian AC4900 is available for $83:

GermGuardian AC4900CA Air Purifier at

Replacement filters are also at Amazon, around $33;

GermGuardian FLT4825 True HEPA Filter B at

Amazon also carries the UV-C lamp, around $20:

GermGuardian LB4000 UV-C Lamp at

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