too many filters this unit worked well when I first got it, but now 6 months later the motor has become very noisy. also, I have to change the filter very often - I think they only last ~1-2 months. I would recommend a more powerful purifier unless you are going to use it in a very small room....more info
A good unit plauged by expensive filter cartridges Air Purifiers always seem to have mixed reviews from various buyers based on the conditions if they work or not. The truth of the matter is, the most expensive air purifier out there money can buy will probably be as if not the same efficiceny as these smaller purifiers granted they are under one condition, and that is the user(s) actually need the unit in the first place.
This Holmes unit is an "improvement" over their previous HAP422 model which was the larger standing tower model. Although the previous model supports a larger room, the unit was plauged by the fact that it was horribly noisy and that the LED lights had a tendency to burn out.
The HAP412 is essentially a cut down version of the HAP422, and only covers a room with 120 Sq Ft. Gone are the led indicators and replaced with nothing but a sticker indicator telling you how to notice if your filters are clogged. Other than that, they are similar in appearance and function.
Here is a simplified pros and cons of the unit.
1) It's small and has a swivel base that turns 45 degrees.
2) Like most HEPA certified units, it works as intended.
3) The fan is quite strong on Medium and Large settings.
1) The fan is quite noisy on Medium and Large settings.
2) Replacement filters are very expensive. Filters are suppose to be changed every 3 months, at $12.50 a filter, that's $50 dollars of upkeep during a year!
3) Not easy to clean the exterior, you have to pay some attention and time to it.
Generally speaking, the Holmes HAP412 unit is successful at what it does, cleaning your air. However, the unit's biggest downfall in my opinion is that the replacement filters for the unit are through the roof. I would recommend you buy this unit only if you are for sure you know or have allergies, have a small room, and need a device that has basic HEPA functions to serve your needs. After the initial year, the unit will essentially cost $90 dollars and $50 more dollars every year there after. I recommend buyers to buy the filter packs when they buy the unit so that have enough for 1 year's worth of usage without the need to go out and search for filters later. It's also a burden on your wallet/purse since you're making less of a trip to get them and if you buy it online, are saving shipping costs.
As for all HEPA units and air purifiers, always make sure you have a need for the device before you buy it. Any device, no matter how fancy or large, will not work for you or cause any noticeable differences if you do not need the unit. If you live in a dry, well ventilated area with few flowering plants, then any air purifier will be useless to you. Likewise, those who live in confined spaces or the basement with their windows closed most of the day or their rooms having very poor circulation, then an air purifier will greatly benefit them.
Smokers and carpet owners be weary. As staed on various air purifier websites, the smoke from the cigarettes and the dust from the carpets will overwhelm your air purifier quickly. For example, a smoker in a carpet room with have his purifier cut in half of effectiveness. (Like the HAP412, it will only cycle 60 Sq Ft than 120 Sq Ft) The filters will also need changing more readily, from 3 months to every 2 months. ANY person who smokes and has carpet floors pays this steep price as long as they decide to smoke indoors and not vacuum the floors daily.
For it's worth, the Holmes HAP412 works as a powerful PERSONAL air purifier. The unit's capacity just isn't strong enough for a large or even medium sized room, but luckily the fan is strong on the unit and so is the intake. It's a good starter to unit to see if you really want to try out air purifiers and have some allergy problems, and at $45 dollars, it's a cheap experiment. Those who suffer from severe allergies should look elsewhere however, and invest in those very expensive professional grade units that hospitals use. (Just a warning, they reach up to $2500!)
Sleep with the unit all night with your windows closed on the very first day your purchased it. When you wake up, see how you feel and make sure to pay attention to your eyes and your nose. If your eyes feel fine (moist) and your nose feels light, then the air purifier is doing its job. Also make sure to leave your closed filtered room and into your living room or go outside for a moment. If you notice your nose acting up (sniffing) or your eyes becoming dry or irritated, then it's also a sign that your air purifier is working. It's also a sign that you are prone to allergens in the air.
If you feel completely indifferent with the unit on or off, then return it to the store. You do not need any air purifier, and you're ok without them! (Lucky you as well, since that means you're also not allergen prone)...more info