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Guardian Technologies™ FAQs


How do I determine what air purifier I need based on my room size? 

Small rooms, often below 100 sq. ft. may only require a tabletop or mini tower-style air purifier to circulate the air. Medium rooms that range between 100 sq. ft. and 170 sq. ft. will typically need a floor model that has a larger filter to effectively process the air in the room. Large rooms, over 170 sq. ft. will require a full size tower or box style unit. Most air purifier cartons offer specific information on room size or square footage covered by the air purifier.

What is HEPA?

HEPA stands for “High Efficiency Particulate Air.” A HEPA filter must capture 99.97% of all particles that pass through it that are 0.3 microns or greater in size. HEPA is composed of a layer of randomly arranged fibers. HEPA filters are often used in airlines, vacuum cleaners, cars, etc.

How often do I need to replace my filter?

GermGuardian® air purifier filters should be replaced every 6–8 months depending on use.

How do I know I need to replace my filter?

You will know your filter needs to be replaced when the filter turns from white to gray or black.

What is CADR?

CADR stands for “Clean Air Delivery Rate” which indicates the volume of filtered air delivered by an air purifier. CADR ratings show the effectiveness of how efficient the air purifier is at capturing fine particles, such as: tobacco smoke and plant pollens.

What is a carbon filter?

Carbon filters are also called charcoal or activated charcoal/carbon filters. It is a form of carbon that is extremely porous making it excellent at absorbing. Carbon filters can absorb a variety of chemicals and vapors simultaneously.

Is my filter washable?

The pre/charcoal filter layer that attaches to the HEPA portion of the filter can be cleaned using the brush attachment tool on your vacuum cleaner. Once the HEPA portion of the filter turns from white to gray or black, the filter must be replaced entirely.

How often do I need to replace my UV-C bulb?

Your UV-C bulb in GermGuardian® air purifiers, model series AC5000 and AC4800, need to be replaced every 10–12 months depending on use. Other GermGuardian® air purifiers and air sanitizers, including: AC3900, AC4000, AC4010, LW9 and LW18 are designed to last the lifetime of the product. If for some reason the bulb in one of these models is not working, please contact Customer Service at


or support@guardiantechnologies.com.

How do I know when I need to replace my UV-C bulb?

You will know your bulb needs to be replaced when it starts to flicker, turns a yellowy/orange color or stops working completely.

What is the air purifier warranty? 

To read the full warranty, click here.



What is ultrasonic?

Guardian Technologies™ PureGuardian® humidifiers use a metal diaphragm vibrating at an ultrasonic frequency to create water droplets that are expelled out into the room to help maintain the desired humidity level. An ultrasonic humidifier is virtually silent when operating.

What is a recommended/comfortable humidity level?

A recommended level of humidity for your home is 40–55%.

What is silver doing in my humidifier?

Silver Clean™ technology is a form of micro-silver crystal technology. The silver has been embedded into the water tank as a fungi-static agent to fight the growth of mold and mildew on the surface of the water tank. Silver’s antibacterial powers are being applied in a variety of household and textile products and applications.

Can I add scents, medications, oils, etc. to my water tank?

PureGuardian® Ultrasonic Humidifiers can NOT have scents, medications, etc. added to the tank. These substances will clog up and prevent the humidifier from functioning properly.

Will my humidifier shut off when the water tank is empty?

Yes. All PureGuardian® Ultrasonic Humidifiers automatically shut off when the water tank is empty.

Does my humidifier have a filter to replace?

No. PureGuardian® Ultrasonic Humidifiers do not have any filters, wicks or evaporating pads to clean or replace.

What should I do before putting my humidifier in storage?

Prior to putting your PureGuardian® humidifier away be sure to pour out any excess water and clean out/wipe down the surface with a soft, damp cloth. Be sure to let the entire unit air dry completely (24-hours) before storing.

How often should I clean my humidifier?

PureGuardian® humidifiers should be cleaned every 1–2 weeks, depending on use. If you have hard water or water with a high mineral count, you may need to clean your humidifier more often.

How should I clean my humidifier?

Instructions for cleaning your humidifier: Wash the spray cap, spray spout and water tank lid (the lid on the bottom of the blue tank) with a mild dish washing soap, rinsing well and drying thoroughly. The blue water tank can be rinsed with warm water and dried.

Drain any excess water from the base area. The ultrasonic disk should be cleaned frequently, using diluted white vinegar. Let the diluted vinegar soak in the disk area for 4–5 minutes, then use the brush provided and gently clean the disk. Do NOT scrub. Drain any excess diluted vinegar and dry with a soft cloth. 

You can use diluted vinegar and wipe the rest of the base of the humidifier. We do not suggest running anything through the humidifier.

Why is there white dust on my furniture?

If water is especially hard or has a high mineral content, you may notice white dust around the unit. White dust is not a problem it is from the minerals in the water that form the dust. The humidifier evaporates the water and then the white dust is left in the unit, not sent out into the air. If bothersome, use distilled water or you can purchase one of our Decalcification Filters (FLTDC) to help with the problem.

What if my tank starts to leak?

If your tank begins to leak, first check that it is on a flat level surface. Next, check that the tank lid is screwed on tightly in place. Also, check that the tank itself is securely and properly installed on the humidifier base. If the unit is still leaking, please contact Customer Service at


or support@guardiantechnologies.com.

What temperature water should I use in my humidifier?

Room temperature water should be used in your PureGuardian® humidifier. Your humidifier will warm the water and maintain the necessary water temperature for warm humidification.

Where should I put my humidifier when it is running?

It is recommended that you place your humidifier up and not on the floor. Placing the humidifier on a table or nightstand during operation is suggested. Do NOT place on carpet, towels, blankets or other uneven or absorbent surfaces.

What type of water should I use in my humidifier?

Distilled or regular tap water can be used in your humidifier. Some tap water is high in mineral content and will cause a mineral build-up, so distilled water is preferred.

What is the humidifier warranty?

To read the full warranty, click here.