GermGuardian AC4825 Review – Top-Selling Air Purifier

Full Review

The GermGuardian AC4825 is a simple air purifier with an industrial design that is one of the best-selling models on the market.

This air purifier is perfect for those who want fresh, clean air without dealing with overly complicated features.

The AC4825 has three fan speeds, uses four-stage filtration technology, and is very affordable.

It also includes a UV-C light, which is designed to kill germs and mold spores.

We tested its performance, noise levels, and power consumption and thoroughly analyzed its specifications to determine whether it’s worth buying.

How We Tested the GermGuardian AC4825?

1. For the filter efficiency testing, we used the Temtop LKC-1000S laser particle meter, which measures PM2.5 (µg/m3), PM10 (µg/m3), Particles (per/L), and HCHO (mg/m3) in the air, and also calculates the AQI.

2. We placed the GermGuardian AC4825 in two separate performance tests, one in a 194 sq. ft. (18 m²) room and the other in a 320 sq. ft. (30 m²) room. Then, we recorded the initial air quality values using the Temtop laser particle meter and let the GermGuardian AC4825 run at maximum speed.

3. After 60 minutes, we measured the new values using the Temtop laser particle meter and saved the data.

4. Next, we placed the GermGuardian AC4825 in a glass box, which we then filled with smoke. Then, we measured how much time was needed for the air purifier to remove all the smoke from the box.

5. Using a special noise measurement tool, we tested the air purifier’s noise level at all speeds. We measured the noise level on the dBA scale.

6. Finally, we measured the power usage at all speeds using an energy meter, after which we calculated how much it would cost to use the device at a particular fan speed for one month. For reference, we used an energy price of $0.12 per kWh.

We tested the performance of the GermGuardian AC4825 using our well-established testing methodologies.

We placed it in two different rooms, where we measured how much it improved air quality over 60 minutes while operating at maximum speed throughout the test.

For this test, we used the Temtop laser particle counter, the same device we rely on for all our performance tests.

Testing in a 194 sq. ft. (18 m²) Room

In the first test, performed in a 194 sq. ft. (18 m²) room, the GermGuardian AC4825 delivered solid results.

It improved air quality by 92% in just 60 minutes while operating at maximum speed with the UV-C light turned off.

In comparison, as you can see in the chart provided, only a few air purifiers performed significantly better.

However, the Levoit Vital 100S, for instance, improved air quality by 95% in the same test.

Testing in a 320 sq. ft. (30 m²) Room

In the second test, performed in a 320 sq. ft. (30 m²) room, the GermGuardian AC4825 delivered slightly lower but still good results.

In 60 minutes, it improved air quality by 90%, which is a confirmation of high efficency filters.

We repeated the test with the UV-C light turned on, and the GermGuardian AC4825 managed to improve air quality by an additional 1% compared to when the UV-C light was off.

Performance – Smoke Removal Test

The GermGuardian AC4825 doesn’t use a pellet-based activated carbon filter. Instead, it uses a fibrous filter coated with carbon.

This likely explains why it performed slightly slower than expected in the smoke test.

It took 38 seconds to remove all the smoke from the glass box—while not the best in its class, it’s certainly not the worst either.

Many air purifiers performed significantly slower; for instance, the Aroeve MK01 needed 139 seconds to clear the smoke from the glass box.

We tested the noise levels of the GermGuardian AC4825 at all speeds using a specialized noise measurement tool.

The unit has three fan speeds, and while it operates quietly at higher speeds, it could be much better optimized at the lowest speeds.

At the first speed (the lowest), it produces a noise level of 46.7 dBA, which is noticeably louder than some competing air purifiers. For instance, the Winix A231 operates at just 40.2 dBA at its lowest speed, making it nearly 7 dBA quieter.

However, the AC4825 is much better optimized at its second and third speeds, producing less noise than similar air purifiers. At maximum speed, it produces only 54.2 dBA, which is the quietest noise level among all the air purifiers I compared it to (see the chart above).

One clear takeaway is that the GermGuardian AC4825 would highly benefit from a sleep mode, which could significantly reduce noise at the lowest speed, making it more suitable for bedroom use for example.

One of the major drawbacks of the GermGuardian AC4825E air purifier is its use of a 50W motor. For the CADR it provides, this is quite a large motor and could have been better optimized.

Additionally, when the UV-C light is activated, it consumes an extra 5W. While this isn’t a significant amount compared to other household appliances, it is notably high for an air purifier in this category.

If you were to run this air purifier 24 hours a day at maximum speed for an entire month, your electricity bill would increase by approximately $3.78. This is undeniably the highest energy consumption among all the air purifiers I compared (see the chart below).

For this calculation, I used the average electricity cost in the U.S., which is $0.12 per kilowatt-hour.

As shown in the chart, the Levoit Vital 100S consumes nearly 30% less energy while delivering better performance and a higher CADR. Other models also stand out—for example, the Coway Airmega 100 would raise your electric power bill by only about $1.95 under the same conditions.

On the positive side, the GermGuardian AC4825E doesn’t consume energy when in standby mode.

However, in addition to electricity consumption, there is the recurring cost of replacing filters, which need to be changed on average twice a year.

Although it is Energy Star certified, the motor’s lack of optimization and the filters short lifespan make the GermGuardian AC4825E more expensive to maintain annually.

Design

The GermGuardian AC4825 uses a tower-shaped design. This tower-like design is proven to be useful because it can be placed in tight spots. GermGuardian company usually makes air purifiers in this design because they are more practical, especially if you don’t have too much space in your home, office, or anywhere you want to.

I tested a black GermGuardian air purifier, but if you don’t fancy black color, and if a white air purifier would fit better in the interior, you can go for it. This company provided two different colors of this gadget.

The black color is the brand of this GermGuardian model, and almost the whole device is in black. Only the top is in silver color with a blue line that emits light. On top is the control panel. However, there are not many options to use, the UV-C light button and fan speed knob. On the back of the air purifier is also a hole that is used for transport. You can transport it with one hand. The overall design is nothing special.

Control Panel

The GermGuardian AC4825 is pretty straightforward to use as it does not contain many options and keys that could confuse you when using it. There are only a power knob and UV Light button to operate this device.

As already mentioned, the device is turned on with a power knob. By moving the knob in the clockwise direction, you can also control fan speed. AC4825 has three speeds; low, medium, and high. 

By turning the power knob, you also control speed and turn the air purifier on or off. UV-C light button is also a filter replacement button that is used to reset the filter replacement period. 

A button with UV letters is used to turn the UV-C bulb on. This button is also used to reset filters and UV-C light. I will talk more about the reset function later in the review.

In the end, when the air purifier is done with the job, you can turn it off by moving the power knob back into a default position.

Airflow

The GermGuardian AC4825 has an air inlet on the back, and on the front is an air outlet, so keep that in mind when you want fresh air delivered directly to your face. If you would rather the device not blow right into you, you can turn the device away.

The air outlet is located only on the front side of the device, so you will easily manage it and determine where you want it to blow fresh air. The freshness you will feel after the device cleans the air in your room is inevitable.

Size and Dimensions

GermGuardian AC4825 is tall (9 x 5.5 x 22 inches) but small, with only 8.55lb in weight. It also has a handle on the back for easier transport. You won’t have any problems moving it from one location to another.

Accessories and Parts

GermGuardian Company provides you with all the necessary parts for initial use. Be sure you will get all the essential accessories and components that will be used most commonly. 

You will get the GermGuardian AC4852 all assembled and, you can turn it on immediately without any additional actions required. 

All parts and accessories that come in a box are an air purifier, a true HEPA filter, and a pre-filter that is a combination of a pre-filter and charcoal filter. Also, you will get a UV-C bulb and a user manual. 

Features Overview

Certified Device

GermGuardian AC4825 is a certified device that guarantees quality. It has EPA, CARB, Energy Star, and AHAM certificates. In other words, you can’t go wrong with the GermGuardian AC4825 air purifier if you only look at the certificates.

No Ozone

GermGuardian AC4825 is free from ozone, and that is true! Proof of that is the CARB certificate. Some air purifiers produce ozone, but AC4825 is certainly ozone-free.

Silent at Work

Silence is essential for the bedroom because loud noise can bother your sleep. Don’t worry about this GermGuardian gadget; it is quiet enough, and you will be able to sleep like a baby. Turn the AC4825 air purifier on at the first speed and breathe clean air during the night.

Room Coverage

This GermGuardian model device is built for up to 167 sq. ft. rooms. In the recommended room size, this device will perform best. Below, you will find out how great the GermGuardian AC4825 air purifier performed. However, if you need an air purifier to use in a larger room, you will need a more powerful gadget. In this case, take a look at the Levoit Core 300 model.

The UV-C bulb is turned off by default, if you are suspicious about UV-C light function, you never have to turn it on.

Warranty

A three-year warranty from GermGuardian is more than generous. However, you will need to register your device on the GermGuardian website to use the full three-year warranty. But I have to emphasize that the warranty doesn’t apply to the filters or the UV-C bulbs. We should purchase them on our own. 

Room Coverage and CADR

CADR ratings are the way you can see the difference between the filtration power among air purifiers. Each rating is important, and you can pick an air purifier that best fits your needs. 

For example, if you have smoke or odor trouble at home, then look at CADR for a smoke. Check out the table below with all the CADR ratings of GermGuardian AC4825.

The GermGuardian AC4825 is intended for rooms up to 167 sq. ft. and will fit the living room, bedroom, or any other room in the above-mentioned dimensions best.

How does the room coverage of the GermGuardian AC4825 compare to other similar air purifiers?

Device	Suggested coverage (sq. ft.)
GermGuardian AC4200W	up to 105 sq. ft.
Winix 5500-2	up to 360 sq. ft.
Levoit Core 300	up to 219 sq. ft.
Levoit LV-H132	up to 129 sq. ft.
Smartmi P1	up to 320 sq. ft.

Filtration Technology

The filter is the most important part of every air purifier. All airborne pollution, dust, pollen, pet dander, hair, and even mold spores are removed with a filter. 

The filter is delicate and needs to stay dry for maximum performance. Because of that, never use an air purifier in areas with high moisture. The filter is not reusable, which means you should never wash it or clean it. These actions may damage the filter, and you can have even more pollution at home than before.

True HEPA Filter

GermGuardian AC4825 has four layers of filtration. The most significant layer of air filtration is a True HEPA filter, which stands for High-Efficiency Particulate Air. It destroys up to 99.97% of harmful germs, dust, pollen, pet dander and hair, mold spores, and other allergens as small as 0.3 microns from the air. 

We keep the True HEPA filter at top performance by using pre-filter and regular filter replacements. You will notice a red light blinking on the top of the AC4825 air purifier when it’s time to change the filter. If used properly, the filter needs to be replaced every six months.

Pre-filter + Charcoal

GermGuardian is specific because the filtration system includes two additional air filtration layers, a pre-filter, and a charcoal filter.

The pre-filter + charcoal layer of filtration is significant for catching larger particles like pet hair, and it increases the lifespan of the HEPA filter. Though AC4825 has two extra layers of air filtration, a combination of pre-filter and charcoal is not the happiest combination because this means that there is not much carbon to remove all the bad smells in the room. However, charcoal pre-filter will still be useful for removing odors at a decent time. It would be much better if, instead of a charcoal filter, a carbon pellet is used.

Nevertheless, pre-filtering removes larger particles, dust, and some allergens. The charcoal filter prevents excessive accumulation of odor but also reduces the growth of bacteria, germs, and mold. Hence, your GermGuardian AC4825 will get rid of all these impurities from your home and prevent you from inhaling them.

UV-Light

The latest stage of filtration is the UV-C light. UV-C light, usually named Ultraviolet Germicidal irradiation, is proven to be extremely effective at killing germs, mold spores, and even some viruses. This advanced technology is part of the air purifier and can be turned on or off at any time. UV-C light is not the only technology that cleans the air in the GermGuardian air purifier; this popular air purifier also uses a pre-filter, HEPA filter, and activated carbon filter.

How to Replace the GermGuardian AC4825 Filter?

UV-C Bulb

UV-C light is one of the best ways to kill dangerous microorganisms. Many manufacturers started to use UV-C light in their air purifiers to provide even greater performance.

The GermGuardian AC4825 UV-C bulb position is not the best. It would be much better if it were placed somewhere in the middle of the device and not on top. UV-C light technology works with Titanium Dioxide. Titanium Dioxide is activated by UV-C light and, in combination, kills germs but also removes odor molecules, smoke, cooking odor, and even pet odors.

When the UV-C light is on, you will see the blue light on the front panel. UV-C light is safely contained inside the air purifier, and using it is perfectly safe.

How to replace UV-C bulbs?

FAQ About GermGuardian AC4825