GermGuardian AC4825 Air Purifier

It’s about time we reviewed the GermGuardian AC4825, one of the most popular affordable air purifiers on the market. With over 11,000 customer reviews, this highly-discussed model possesses many excellent features for clean, safe, and breathable air in your home.

Our review covers the filtration system, modes, maintenance requirements, and FAQs so you can make the right choice for your 2020 air purifier needs. We also compare it with similar GermGuardian air purifiers AC5250pt, AC4300, and CDAP5500.

What is the GermGuardian AC4825 Best For?

✔ Small-medium rooms

The AC5825 air purifier is best suited to rooms up to 167 square feet, (a medium-sized bedroom or smaller living room). For perspective, the average size of a bedroom (in the USA) is 130 square feet. The slim, tower-style shape fits discreetly into small spaces without a large footprint stealing precious room real estate. 

✔ Smaller budgets

For such a solid, well-functioning machine, the price is very reasonable indeed. What’s more, you can buy two units for the best price on Amazon with a great discount, ideal for equipping two main spaces in your home. You could keep your living space and bedroom purified, without blowing out your power bill as these units are Energy-Star rated and very efficient. 

✔ Food, pet, and smoke odor reduction

The charcoal pre-filter does an excellent job of reducing cigarette, food, and pet odors in the home and office. This is backed up by countless user reviews raving about the positive difference in indoor odors.

Asthma, allergies, and flu season

Thanks to the true-HEPA filtration, allergy and asthma triggers (dust, dander, pollen and more…) are captured before they can set off symptoms. What’s more, the UV-C light kills bacteria and viruses that can be spread through the air, an excellent addition for protecting your immune system during flu season.

An overwhelming number of reviews rave of improved asthma symptoms and barely-there allergies since using this model.

GermGuardian AC4825 Air Purifier tech

Size, Weight, Coverage, and Ratings

CADR: This unit is AHAM verified at 167 square feet, with CADR reports: 

Smoke: 108 cfm 
Dust: 118 cfm
Pollen: 125 cfm

CADR refers to “clean air delivery rate” and indicates how fast the air purifier takes to clear a certain room size. (Learn more about CADR)

Size: 10.25 x 6.75 x 21.5 inches 
Weight: 8.55 pounds 
Coverage: up to 167 square feet 
Energy-Star certified? Yes

GermGuardian AC4825 Air Purifier height

Filtration System

The AC4820 filtration system comprises a carbon pre-filter and a true-HEPA filter referred to by GermGuardian as a “combination filter”. The carbon pre-filter catches large allergens such as dust and pet hair while neutralizing odors such as smoke and pet smells.

The True-HEPA filter catches 99.97% of particles as small as 0.3 microns, which includes pollen, dust, and dander. There is also a UV-C light that activates titanium dioxide to kill living airborne allergens such as viruses, bacteria, and mold. If the UV-C light isn’t your thing, it can be switched off with the press of a button.

GermGuardian AC4825 Air Purifier filtration

Does the AC4825 have an Ionizer?

No, it does not have an ionizer, but it does have a UV-C light that kills airborne viruses. The bulb uses both titanium dioxide and UV-C light to eliminate odors that the carbon filter couldn’t quite manage to capture. Many people fear that the UV-C light will emit ozone (like an ionizer does), but GermGuardian ensures that there are no ozone emissions from the AC4825.

Style, Operation, Modes, and Features 

The AC4825 air purifier has a tower-style construction with a small footprint. There is an air inlet at the back, and outlet at the front, with simple controls at the top of the machine. A manual dial changes the fan speed from 1-3, a button switches the UV-C light on and off, and an indicator light prompts you to check and/or change the filters.

Aside from these simple features, this is a minimal machine in that it isn’t WiFi-enabled and it doesn’t have an Auto mode or air quality sensor. However, this is not a problem considering the very reasonable price and excellent air cleaning abilities, any fancy features would merely be a bonus.

GermGuardian AC4825 Air Purifier sofa

Maintenance and Filter Requirements 

The maintenance requirements are minimal, all you need to do is replace the filters, (which is simple).

How often do the filters need to be changed?

The combination filter (composed of a charcoal/pre-filter and true-HEPA filter) should be changed every 6 months, or more often if your air is very contaminated. When you peel back the carbon layer to reveal the true-HEPA filter, check if it is fresh and white or coated in dust. This way, you can if it’s time to switch out the filters regardless of the filter change indicator light. 

Can the filters be cleaned or washed?

The layer of carbon can be vacuumed, but otherwise, the combination filter cannot be washed or cleaned.

Where can I get replacement filters for the BlueAir Sense+ and how much are they?

The AC4825 requires the Filter B replacement, (model number FLT5825) and the carbon pre-filter pack (model number FLT22CB4). You can find them for the best price on Amazon here. Even when they are not on special, the filter replacements are very affordable even for tighter budgets. The UV-C light bulb can also be replaced, (model number LB4000) and replacements can be found here, for a low cost. The UV-C light bulb should be changed every 10-12 months. 

Comparing GermGuardian AC4825 with Similar GermGuardian Models

AC4825 vs. AC5250PT

germguardian AC5250PT air purifier

These two models are extremely similar and look identical at first glance. However, the 5250PT is a little larger and caters to a slightly bigger room size at 180 square feet. What’s more, the 5250 is also known as the “Pet Pure” air purifier, as it has an antimicrobial layer added to the filter to kill odors and bacteria. (Check AC5250PT on Amazon)

The 5250 has 5 fan speeds for extra cleaning power, while the 4825 only has 3. The 5250 is slightly more expensive, but not by much.

AC4825 vs. AC4300

germguardian AC4300 air purifier

The AC4300 is similar to the AC4825 in the sense that they are both slimline, tower-style air purifiers. They share similar recommended room sizes (AC4300 at 153 square feet, the AC4825 at 167). They both have the same core filtration system (pre/charcoal filter, UV-C light, and true-HEPA filter), however, the AC4300 features the Pet Pure antimicrobial treatment for killing odors and bacteria. Check AC4300 on Amazon or Read our AC4300 Review Here

The AC4300 has a more modern aesthetic with cleaner lines and a shiny finish. Finally, they are similarly priced, with the AC4300 at a slightly higher cost (but barely significant).

AC4825 vs. CDAP5500

germguardian CDAP5500 air purifier

The CDAP5500 is the same as the 4825 in the sense that it’s a tower-style unit, it caters to 167 square feet, and it has the same filters (carbon/pre, true-HEPA, and UV-C). However, the CDAP5500 is more modern as it is WiFi-enabled and can be controlled with your voice via Alexa.

It comes with SmartAQM which is an air quality monitor that works with Auto mode to switch the fan speeds as the air contamination changes. You can keep an eye on your air quality from afar by using this application. As expected, the CDAP5500 is almost double the price of the AC4825. (Check CDAP5500 on Amazon)

Noise and Light 

Sensory aspects such as noise and light levels can make or break a user’s experience of an air purifier. The AC4825 is considered by many to be loud, too loud for some users who reviewed the unit after giving it a fair run. Others find the noise to be at a soothing “white noise” level.

In terms of light, there is a potential downside in the fact that the UV-C light is a very bright shade of blue/violet. It cannot be switched off without switching off the UV-C function, which is a bit of a design flaw. However, you can place a piece of opaque tape over the light to prevent light pollution in the bedroom at night.

GermGuardian AC4825 Pros & Cons

Pros 👍
✔ Effectively reduces pet, smoke, and food odors
✔ Affordable unit and filter replacements
✔ True-HEPA filtration

Cons 👎
✘ Prone to producing plastic or chemical odor at first
✘ Too loud for noise-sensitive people
✘ UV-C indicator light is too bright

Review Verdict

The GermGuardian AC4825 air purifier is an excellent choice for the cleanest air in 2020. As our review outlines, it is very affordable, easy to maintain, safe, and most importantly, effective against odors and allergens.

If after reading this review you’re tempted to know more or want to make a purchase, you can find the unit for the best affordable price on Amazon here.

Frequently Asked Questions

Does the AC4825 produce ozone?

No, the UV-C light does not operate at a high enough level to produce any ozone.

Why does it have a plastic smell?

Many users who left a GermGuardian AC4825 review mentioned a plastic or chemical-like odor. GermGuardian states that this is simply due to new parts being used, and it should be gone after 48 hours of continuous usage. However, some reviews complain of a burning smell and melted parts inside. This is not overly common, but if you do notice a burning smell, turn off the machine immediately and contact the manufacturer.

What is the warranty?

The GermGuardian AC4825 air purifier has a 3-year limited warranty.

How do I reset the filter change indicator light?

Hold down the UV-C button for 5 seconds and the filter change light should turn back to green.

Does the AC4825 have an auto mode or sleep mode?

No, this model doesn’t have any special modes. The very similar CDAP5500 is Wi-Fi-enabled and has an auto mode.