Perhaps "sneaky marketing" is a more fitting word, and yes it is very prevalent. Here are the top concerns:
Here is a list of some of the deceptive practices in the industry:
The SCAM = The problem is that once you've paid for the air purifier and go to buy a new replacement - GOTCHA!.The company can charge you whatever they want. Here are just 2 examples of replacement filter costs in popular models that seem a bit inflated: Honeywell 50250 = $78 (The Purifier is only $210)
IQAIR = $230 (The Purifier is $899, and although the filters are large that's quite a bit to pay)
It reminds me of the days when American cars would not make it to 100,000 miles. Some said that it was to sell parts by breaking down as planned. Otehrs said that because the Japanses cars would last longer that American cars had to improve.
The SCAM = HEPA filters will capture some of the mold spores but will not kill mold on the walls. Those mold spores inside the HEPA can then spread. Look to include an air purifier with either UV light or electrostatic will kill mold inside and on the walls.
As for germs and bacteria - HEPA will not treat those in a room. If the HEPA is specially treated (and some are) with anti-bacterial chemicals then it will kill bacteria and germs inide the HEPA filter, but will not generally kill it anywhere else.
The SCAM Electrostatic plates and grids are positive and negatively charged electrical surfaces that will attract some particles like a magnet. Then you wash them off. And while it will capture some dust by it's "static" charge, most pollen and dust doesn't have a lot of charge. You need HEPA for grabbing most of the pollen and dust.
If electrostatic (Oreck's Truman Cells are an example) really worked there would be no need for HEPA.
The SCAM Washable electrostatic and pre-filters will gather some particles in the air, just not like HEPA. Also the washable "hepa-like" filters are made of foam and don't adhere particles, or filter particle like "real hepa" filters.
Check out the reviews on this site for real information.