In this post we will review the HEPA based air filtration system called GermGuardian AC4825.

If you don’t need some heavy duty cleaning, which is to say if you don’t have a lot of pollution, this system will do a great job of keeping your home completely free of dust.

It will also greatly reduce the smells and odors coming from pets, or for instance cooking in the kitchen.

The Filter Duration

What’s really a nice feature of this device is that the filter may last a full 8 months. That is, if the air pollution in your home is moderate, you will be able to extend the life of the HEPA filter installed within.

Click HERE to see Germ Guardian on

We can think of situations when the filter might not last for so long, for example, if you have a family member who smokes, and he or she does that heavily next to the GermGuardian. In that case you would probably have to replace the filter sooner, but probably not sooner that a good 6 months.

For a normal household, without extreme stuff in the air, 8 months is probably a realistic time window.

That is pretty awesome, including the fact that the filter is not that expensive, between $20 and $30, so you can buy one or two per year without too much problems for your family budget.

Three Modes of Operation

the box

There is a simple dial at the top of the purifier. It has off, low, medium, and high. In addition, you will find a button for UV light.

The UV Light

As far as the UV light goes, you don’t have to use it all the time. The light might last something like a full year if used all the time. And you can replace it afterwards.

But you can turn it on every once in a while. A good rule is to turn it on if you or some member of your family is sick because it might help stop the spread of disease, if it is transmitted by air, like viruses or infections.

When you turn the UV light on, there is a blue light that is not that bright. It is pretty dim, and looks kind to the eye. It reminds like a computer light.

the switch
The dial at the top


On low the noise is very minimal, almost no sound at all.


On medium, there is some sound to it, you can still watch TV though. If you put your hand next to it, you will notice quite a bit of air coming through. It is sucking air from the back side and pushing it up front.


High is a little too loud, almost like a jet engine, but if you are away from it, the noise is reduced again, so you can even use it on high all the time if you are not next to it.

It is probably a good idea to use it a couple of days on the high settings to help you get the ball rolling with respect to cleaning your house air, but then you won’t need the high setting so much.

Three Stages of Filtration:

Three Stages of Filtration
  1. UV light - takes care of the germs in the room, for example, viruses that might give you flue or pneumonia. The UV light is from the C spectral range. The addition of titanium dioxide makes an extra useful function. It is activated by the UV-C light and serves as a decomposing agent for the odor molecules. So, it removes the pet, cooking, and smoking smells.
  2. The next level is HEPA filtration. The HEPA filters catches dust mite, pet dander, and other allergy trigging components of the air. HEPA filters capture 99.97 percent of all particles down to 3 microns in size. So it reduces a lot of smaller particles invisible to the eye. It effectively eliminates all indoor triggers of asthma and allergies. Of course, you won’t see things the filter collects. They are pet dander, small molecules, dust, and mold. They are all practically invisible and float in the air around.
  3. Pre filter and charcoal layer which captures larger particles, pat fur, human hair and similar. It is practically two filters in one: a charcoal and per filter combined that provide basic filtration.

Design and Accessories

the user manual

The instruction is pretty good. It has many pages with detailed description, for example how to change the bulb for the UV filter, warranty information, etc. Don’t throw it away, as you would have to use it again in 6 to 8 months to change the filters or do other stuff.

The actual unit has a pretty cool look to it. With its metal grid on the front side, it resembles a speaker, like a blue tooth speaker.

It is energy star compliant. It won’t raise your electric bill too much. On the back side there is a cover which you can remove. There is the charcoal filter and behind it is the white HEPA filter.

The Dimensions and Performance

GermGuardian AC4825 is 7 x 10.2 x 21.5 inches, weighing about seven pounds. It doesn’t use the electrostatic principle to ionize the air and therefore produces no ozone. That is a plus, since ozone above certain limit is not a healthy thing to have in your house.

This system has a CADR (clear air delivery rate) rating of 100+, which means it is ideal for small to medium sized spaces. It means that GermGuardian can provide at least 100 cubic feet of clean air every minute.


the device in a room
The Design

GermGuardian AC4825 is probably one of the most popular air purifiers available at a very affordable price. The characteristic features of this air purifier include:

  • If you want to clean the air in a small room up to a medium room of 150 feet GermGuardian AC4825 is perfect for the task.
  • It works silently. When you set this system on low, it is rather quiet. Even when set on medium it doesn’t get too loud. Only when set on high, it produces more noise.
  • Extra easy to set-up and clean which makes GermGuardian easy to use. New users will have no problem at all while using it. Moreover, it is extra easy to maintain. You can vacuum the filters every two to three weeks and replace them every 6 to 8 months.

The Bottom Line

If you are considering buying a system with HEPA filter, GermGuardian AC4825 is a machine worth checking out. You don’t have to have a dusty environment to get one.

If you are sensitive to pets, or start develop allergies, have watery eyes and breathing disorders. GermGuardian is meant for medium to large rooms.

If you are doing a big area, you might consider buying a more expensive unit for a couple of hundred dollars.

One of the advantages of this air purification system is that changing the HEPA filter is not as expensive as it is with other systems.

People would buy an expensive air cleaner and after 2 or 3 months or so, they will end up not using them because of the expensive replacement filters.

With this purifier you won’t have to worry for 6 to 8 months, and after that time the filter is not that costly.

GermGuardian AC4825 User Manual (PDF)

See the reviews of people who own this device