What size room is the AC4100 good for?

It is best for rooms up to about 80 sq ft, where it turns the air over nearly five times an hour. In a 338 sq ft room it only manages about one air change per hour, which is too little for real purification.

Does it really have a HEPA filter?

Yes. It uses a HEPA filter rated to capture 99.97% of particles as small as 0.3 microns, plus a carbon layer for odors and a UV-C light stage.

How often do the filter and UV bulb need replacing?

GermGuardian recommends replacing the filter every six to eight months with normal use, and the UV-C bulb roughly once a year. Both are sold separately.

Is it loud enough to bother you at night?

The low speed is quiet enough for a bedroom. The high speed is noticeably loud, so most owners run it low or medium overnight.

Does it have an auto mode or air-quality sensor?

No. It has three manual fan speeds and no sensor, timer or auto mode, so you set the speed yourself.

What comes in the box?

The purifier ships with a filter already installed. The UV-C bulb is included in most units; check the listing to confirm before buying.

Where is the GermGuardian AC4100 cheapest?

At Walmart, for $104.99, as of our latest check.

What do buyers say about the GermGuardian AC4100?

Rated 4.3 out of 5 from 144 ratings.

Where can I buy the GermGuardian AC4100?

3 stores we checked sell it, including Walmart, Staples, Quill.

GermGuardian AC4100

Best price now

$104.99at WalmartChecked 11 h ago

Compared across 3 stores. Prices are checked against each store and labelled with when.

Visit Walmart

GermGuardian AC4100

Best price now

$104.99at WalmartChecked 11 h ago

Compared across 3 stores. Prices are checked against each store and labelled with when.

Visit Walmart

Ask our agent about this product

It checks today's price at every store, compares the alternatives and answers in about a minute.

Price facts

Last seen at $104.99 at Walmart on Nov 10.
Checked at 3 stores.

Our take on the GermGuardian AC4100

The GermGuardian AC4100 is a small tabletop tower air purifier with a three-stage system: a pre-filter, a HEPA filter and a carbon layer, plus a UV-C light. It is 11 inches tall and about 6.5 inches wide, so it fits on a desk or nightstand. Its real limit is coverage: it only turns over a 78 sq ft room about 4.8 times an hour, and a 338 sq ft room just once. That makes it a personal-space purifier, not a whole-room one. Rivals at this size often skip the UV-C stage, but many move more air. Owners rate it well overall, with noise on the higher speeds and filter replacement the common complaints.

Best forBedrooms and small offices under about 80 sq ftDesks and nightstands where floor space is tightAllergy and pet-dander relief in one roomBuyers who want a UV-C stage in a compact unit

Pros

True HEPA filter rated to capture 99.97% of particles down to 0.3 microns
Carbon layer helps with smoke, cooking and pet odors
UV-C light adds a bacteria and virus reduction stage
Three fan speeds with a compact 11-inch tower footprint
Simple top-mounted controls and easy filter access

Cons

Weak coverage: only about one air change per hour in a 338 sq ft room
Loud on the top speed, which is the setting most small rooms need
UV-C bulb needs periodic replacement and adds running cost
No auto mode, air-quality sensor or timer
Small units like this are outpaced by larger purifiers on airflow

GermGuardian AC4100 prices at every store

WalmartNew
In stockSold by Hidden Path Trading Co LLCReturns: Sold by a Walmart Marketplace seller; returns go to the seller under the seller's returns policy.
$104.99Free shippingChecked 11 h ago
Visit Walmart
StaplesNew
In stock
$113.79Free shippingChecked 11 h ago
Visit Staples
QuillNew
Out of stock
$134.29Free shippingChecked 11 h ago
Visit Quill

Store links may earn us a commission. Some prices via Klarna.

GermGuardian AC4100 price history

Lowest price we've seen: $113.79 on Nov 11 at Staples. Tracked across 2 stores since Nov 11.

What reviewers say

4.3 / 5144 ratings

Owners of the AC4100 generally find it effective for bedrooms, offices and other small rooms, and many praise how little space it takes up. The most common complaints are noise at the higher speeds and the cost of replacement filters and UV bulbs.

What people mention

NoiseCriticisedOwners say the low and medium speeds are tolerable but the high setting is loud enough to disturb sleep or calls.
SizePraisedBuyers like that the 11-inch tower fits on a nightstand or desk without taking up floor space.
FiltrationPraisedReviewers report less visible dust and fewer allergy symptoms in small bedrooms and offices.
Filter costCriticisedOwners note that HEPA filters and UV-C bulbs need regular replacement, which adds to the cost of ownership.
CoverageMixedSome buyers find it works well in a single small room but does little in larger or open spaces.
BuildMixedA few owners report rattles or fan noise developing after months of use.

About the GermGuardian AC4100

The desktop Air Purifier with HEPA Filter is perfect for any small size room. The HEPA filter captures 99.97% of dust and allergens as small as 0.1 microns in size such as household dust, pet dander, mold spores, and plant pollens! This compact air purifier circulates the air 1x per hour in 338 square foot rooms and 4.8x per hour in 78 sq. ft rooms, ensuring thorough purification.The carbon layer helps reduce odors created from smoking, cooking, pets, and more. The UV-C light helps reduce airborne bacteria, viruses, mold spores* and works to reduce volatile organic compounds. It is equipped with 3 speed settings.*Tested with Staphylococcus Albus, and Escherichia Coli, Aspergillus Niger, and Phi-X174.

Specifications

Filter Included: YesSource
Fan Speed Levels: 3Source
Width ("): 6.5Source
Color: Black, Titanium, GraySource
Height (")

Questions and answers

What size room is the AC4100 good for?: It is best for rooms up to about 80 sq ft, where it turns the air over nearly five times an hour. In a 338 sq ft room it only manages about one air change per hour, which is too little for real purification.
Does it really have a HEPA filter?: Yes. It uses a HEPA filter rated to capture 99.97% of particles as small as 0.3 microns, plus a carbon layer for odors and a UV-C light stage.
How often do the filter and UV bulb need replacing?: GermGuardian recommends replacing the filter every six to eight months with normal use, and the UV-C bulb roughly once a year. Both are sold separately.
Is it loud enough to bother you at night?: The low speed is quiet enough for a bedroom. The high speed is noticeably loud, so most owners run it low or medium overnight.
Does it have an auto mode or air-quality sensor?: No. It has three manual fan speeds and no sensor, timer or auto mode, so you set the speed yourself.
What comes in the box?: The purifier ships with a filter already installed. The UV-C bulb is included in most units; check the listing to confirm before buying.
Where is the GermGuardian AC4100 cheapest?: At Walmart, for $104.99, as of our latest check.
What do buyers say about the GermGuardian AC4100?: Rated 4.3 out of 5 from 144 ratings.
Where can I buy the GermGuardian AC4100?: 3 stores we checked sell it, including Walmart, Staples, Quill.