GermGuardian AC5250PT Pet Air Purifier Review

GermGuardian AC5250 "Pet" Review

There was a big surge in air purifier sales 2004-2009, but GermGuardian burst on the air purifier market scene after the 2009 peak.

It had seemed like up was the only way, soon the market began to falter, but GermGuardian worked hard and supported their products better than most.

GermGuardians, competitive on both price and service, are among the top selling air purifiers at Amazon.

There are numerous new Guardians, but the $127 GermGuardian AC5250PT "Pet" 28-inch tower air purifier is selling well enough to collect 799 Amazon buyer reviews, averaging 4.3 stars.

About 10% are negative reviews (one and two stars), most mentioning initial odor issues with new and replacement filters.

There is NO remote, NO Automation, or sensors.

Digital controls atop the 28 inch digital tower AP5250 are flush buttons that modulate the fan speed (1-5), a UV button, a timer, and an on/off switch.

AC5250pt is advertised as having "125-plus" CADR, but is NOT LISTED in the official tables.

With throughput numerics in short supply, we'll be forced to use Guardian's room size recommendation - "up to 199 sq. feet."

I suggest a room MAX of 120 sq. ft., air purifiers work better in smaller sized rooms.

Filter Train

AC5250pt is plug-n-play, use it right out of the box, little assembly required. guardian ac5250pt

Guardian's True HEPA Filter captures 99.97% of .3 micron particles, and is coated with Pet Pure Treatment, an antimicrobial agent.

Guardian 5250 uses just one (FLT5250PT), single combination filter with multiple levels: HEPA, charcoal layer Pre-Filter.

Filter replacement interval, 4 to 12 months, is the sticking point for the "Pet."

Switching filters at 4 months, as some pet owners have been forced to do, runs a filter tab of $160 annually.

Then there is the small 8-watt UV-C lamp (10-12 months), at $26.

The filter is easy to remove and replace, and a reset button for the filter reminder is handy.

Carbonized fabric, maybe an eighth of an inch thick, is layered atop the HEPA as a prefilter.

The PCO (below) is obviously being leaned on for odor control.

I would remove the back once a week and vacuum the filter.

A piece of no-see-um fiberglass mosquito screen could likely save hundreds of dollars in HEPA costs.

AC5250 inhales from the rear and exhausts front with a left-ward bias.

This has two effects.

First, AC5250 can NOT be placed flat against a wall or furniture.

Second, some users are disconcerted by the slant wise exhaust flow.

AC5250pt's switchable 8-watt blue UV ring is bright, but some user reviews say pointing it away from the bed works well.


Many buyers have no idea about photocatalytic air cleaners ( PCO ).

What I see frequently is the supposition that ALL UV lamps create ozone, which is NOT true.

Mercury vapor UV lamps can emit several spectral peaks, some are accompanied by UV radiation, some are not.

Germicidal claims their GermGuardian AC5250pt does not emit UV-A or B, instead it emits UV-C at a distinct frequency, without ozone emissions.

Ultraviolet radiation strikes a Titanium Dioxide film on an Aluminum plate, causing electrons to activate to a higher energy level, creating oxidants.

Primarily hydroxyl and superoxide radicals, these oxidants operate at the molecular level, eating odors, killing microbes, and oxidizing fine particulate.

Notice that the particulate destroyed by PCO is very fine, .1 micron and smaller.

What is important is these oxidants do NOT persist (as ozone does) in indoor air.

Flip the switch, the PCO dies in seconds.

UV-C comes from a 7 Watt Mercury lamp - not much power - scheduled for renewal every 10-12 months.

Many users say they put black electrical tape over the blue UV ring.

Lamp disposal is regulated by EPA, lamp buyers are supposed to send the old bulb in for EPA-approved disposal.

Never LOOK at a lit UV lamp, don't touch the tube.

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

AC5250pt's UV lamp does have a dedicated on/off switch.

GermGuardian AC5250's PCO has a good reputation as a routine home odor eater.

Emissions & Utility

Overall a quiet air cleaner, AC5250 can be loud on high.

Some reviews say they sleep on low fan speed, with a few saying "two," and the majority at three and higher.

Many user reviews complain of smells (BREAK-IN ODOR) when new and replacement filters are installed.

These last from 10 minutes to 10 days, bothering a small minority of buyers.

No remarks concerning persistent odors are present.

GermGuard AC5250 is on the California Air Board's (CARB) approved air purifiers list (ozone less than 50 ppb).

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

Burning 63 Watts on high, and using 125 as the Dust CADR number, I get 2.01 CADR per Watt, very close to the the lower limit (2.0 CADR/Watt), good enough for EPA.

Measuring 9.1 by 6.7 by 27.6 inches, AC5250pt is small enough for most applications.

Weighing just 11 pounds, with a built in handle, AC5250 can easily be moved.

AC5250pt 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" says the warranty is "5 years," but I wouldn't bank on a big windfall warranty claim.

Purchase was just $145, shipping costs hafta be at least $60, they will charge you for parts and labor, and there is some insurance risk of loss/damage in post.



attractive style
reasonable price
small tower 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 to filter outgassing

GermGuardian AC5250pt, the air purifier, is available for something around $127:

GermGuardian AC5250PT Air Purifier at

HEPA Filter C is $35:

GermGuardian FLT5000 GENUINE Replacement Filter C at

GermGuardian LB5000 UV-C Bulb AC5250PT Air Purifier at

Germ Guardian AC5250PT can use the 2-piece FLT5250PT filter, OR the Germ Guardian 1-piece FLT5000 filter.

GENERIC prefilters come in four-paks now, at about $18 each:

Four-Pack Carbon Pre-Filter ( fits Filter C ) at

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