The Friedrich C-90B Air Purifier was a historically bestselling electrostatic air purifier that has now been discontinued. Below are our most frequently asked questions about this air cleaner model.
How quiet is this air purifier?
Whether or not something is loud is often times subjective to the particular customer. However, this unit does have three different fan speeds, and some customers choose to use a lower speed while sleeping and a higher speed during the day. Below is a chart that shows decibel (dBA) readings taken 3 feet away from some common household sounds.
||Oscillating Fan (medium speed)
||C-90B (low fan setting)
||C-90B (medium fan setting)
||C-90B (high fan setting)
Can the air purifier cover multiple rooms?
All air purifiers that we are aware of are most effective in the room that they are operating in. Air purifiers rely on air to pass through the unit in order to be cleaned. Therefore, this will limit the area that can be effectively purified without creating a "tornado" effect in your home. You can expect excellent purification in the room the unit is placed in and some degree of purification in adjacent spaces, depending on the amount of open air flow.
What size room does the C-90B cover?
This unit is rated to cover 506 square feet. However, air purifier space measurements are based upon specific test conditions. This includes average height ceilings, specific placement of the unit, one large open space, etc.
How many filters are there?
This unit has 3 filters: the pre-filter, the main filter, and the carbon filter.
How often does the carbon filter need to be replaced?
The activated carbon filter on this unit acts to remove odors and gases from the air. The carbon in the filter becomes saturated overtime. However, the length of time that it takes for the carbon to become saturated will vary based upon the environment that the unit is operating in and also how often and at what speed the unit is run. An estimated life for the carbon filter may be from 3 to 9 months. Under normal operating conditions, the carbon filter should last for 6 months. NOTE: The carbon filter must be in place for the air cleaner to operate.
What filters need to be replaced?
The only filter that is typically replaced is the carbon filter. The main filter is typically washed and the pre-filter can be cleaned. After a period of time, a customer may choose to replace the pre-filter if they believe that it has torn or is no longer effective.
How does the Friedrich C-90B differ from the discontinued C-90A?
The C-90B is almost identical to the C-90A. In our comparisons, the only noticeable difference that we have detected in the units is the clean air delivery rate (CADR) and range have both been improved in the newer C-90B. We have had very positive feedback from our customers on both the older discontinued C-90A and the newer C-90B. Please call us if you need further information.
Will this unit eliminate dust from my home??
Although this unit is fantastic at dust removal, in comparison to other units on the market, we like to set our customers expectations appropriately: This unit will not eliminate dust from your environment — it will only reduce the amount of dust. Dust comes from so many different sources and, often times, adheres to the surfaces it comes in contact with. Because of this, it is practically impossible to completely eliminate dust altogether. Please call us if you need clarification or additional information. We would be happy to discuss our positive customer experiences in regard to the reduction of dust with this unit.
How much electricity does the C-90B require?
The filter only uses about as much electricity as a household light bulb—as little as 40 watts on the low fan setting.
How do I clean my unit?
To clean the electronic cell and maintain optimal performance, lift the cell out of the unit and submerge it in a bathtub or other suitable container with water and mild detergent. Alternatively, you can simply place the electronic cell in your automatic dishwasher.
What is the difference between the C-90A and the C-90B?
The C-90A was discontinued in mid-2006. The C-90B is virtually identical in appearance, but features an improved fan with greater airflow for increased coverage.
What color is the unit?
The unit is an off-white/cream color.
Disclaimer: Sylvane.com makes this FAQ information available to you without prior official review, but instead with information obtained from discussions, other customers, emails, vendor literature, general industry consensus, and other sources. As such, some of the information on this page may be from subjective sources or may be inaccurate. This information may contain errors and ommissions. Use at your own discretion. Sylvane.com assumes no liability for any damage that may occur due to your use of the information herein.