A Great HEPA Filter

I have a great personal experience with this unit. This is a HEPA (High Efficiency Particulate Air) purifier, highly rated by many independent reviewer panels such as consumer reports and consumer search. Many of us like to spend as little money as possible and buy the best product in the world. Unfortunately, that is unlikely to happen. It is more important to balance your needs with your spendings.

If there is one thing I must advocate in shopping air purifiers is to take note at the CADR (Clean Air Delivery Rate) numbers. A CADR value indicates the rate of clean air generated by a purifier and the number is independently certified by AHAM (Association of Home Appliance Manufactures). A 100 CADR purifier can deliver 100 cubic feet of clean air in 1 minute.

First thing first, this purifier is a real HEPA purifier with a 250 CADR rating. A HEPA filter has a 99.97% capture rate for particles that is 0.3 micrometer. Due to aerodynamic capture mechanism, a HEPA filter usually has a higher or equal capture rate for particles that are larger and particles that are slightly lower -- down to 0.01 micrometer. This includes the usual airborne allergens like pollen, fine dust and smoke particles. Purifiers marketed as "HEPA-type" are not HEPA and fall short of its requirement. Next, not all HEPA purifiers perform the same. This is because HEPA only specifies the particle capture rate of the filter, but if air is not flowing properly through the filter, then it does nothing. An extreme example is an idle HEPA purifier, which has no cleaning power. Most purifiers under $200 have leaks around the HEPA filter, so majority of the air bypass the filter. Honeywell 50250 has minimal air leak, therefore all air moves through its HEPA filter and is purified -- an important point verified by several air purifier reviews.

The 50250 also has a permanent HEPA filter, which can be easily regenerated using a household vacuum cleaner. Most HEPA purifiers require ~$100 annual filter replacement cost, so a permanent filter is a definite plus. In the event which you have to change this permanent filter, the replacement cost is ~$80, reasonable. The unit is extremely easy to use. You can literally change the filter with one hand. No tool is needed. All assembly pieces are large and sturdy, so you will not misplace or break them. Except I suppose, you can break the HEPA filter if you jump on it. Even then, the HEPA filter is sturdier than most other filters. The Honeywell 50250 also has an activated carbon prefilter, which is suggested to be changed every 3 months. Each prefilter costs ~$10, so it is $40 annually. It is important to note that the purpose for the activated carbon filter is two fold. Large visible particles can clog up the filter very fast and shorten its lifespan. The carbon prefilter acts as a pre-screen, trapping the larger particles. As mentioned, a HEPA filter is effective for particles as small as 0.01 micrometer, but it cannot eliminate odors, which are mostly chemicals on the scale of nanometers or sub-nanometers. Activated carbon is a highly porous material which can trap aerosol chemicals. If you do not need to eliminate odor and simply using the prefilter to trap large particles, then you can get by changing your prefilter maybe once a year. You can also remove large particles from your prefilter by using a vacuum cleaner. If you need to eliminate odor, then you will have to change the prefilter often because activated carbon slowly deactivates in a time course of 3 months. Please note that this lightweight prefilter can only removing trace level of chemicals, not high concentration of toxic gas. Another advantage of this unit is that it has a lengthy 5 year warranty. Although Honeywell 50250 is marketed under the Honeywell brand name, it is actually produced and supported by Kaz. I have great experience with Kaz customer support. I have emailed them many questions and they always reply within 2 business days.

This unit wobbles slighting (1-2mm) when running at the lowest fan speed. This is not because the unit is imbalanced. It has to do with HEPA is a highly dense material, so it takes a certain pressure gradient before air can pass through the HEPA filter. At the lowest fan speed, it takes about every quarter second (0.25s) for the fan to create enough vacuum to get the air to pass, so filtered air is "pulsed" out of the exhaust. Consequently, the unit wobbles. The wobbling does not create additional noise.

50250 is very loud at high fan speed, and noticeable at low speed. The noise is caused by the high air flow through the outlet. Filtered air pushed out at high speed allowing better air circulation, preventing the filtered air from immediately draw back into inlet of the purifier. Having filtered air immediately draw back to the purifier is a waste of energy and performance and is a common problem for some of the quieter purifiers. Nevertheless, there are other high quality purifiers which are much quieter. The power consumption is also high for this unit: 50/120/170W at the three speed settings. The purifier has a solid handle and only weighs 20.1 lbs, so it is easy to move around. It is not a small size unit. It has a dimension of: 17" in diameter and 18" in height. This unit is not very stylish.

To reiterate my earlier point, there is no perfect purifier for everyone. It has to do with your priority. For me, the most important attributes of an air purifier is the purifying ability, reliability and low maintenance. Quietness, power consumption and stylish are secondary to me, especially I do not operate the unit 24/7. The money saving of the permanent HEPA filter more than compensates the higher electrical cost. Consequently, I really enjoy 50250, but every customer should make his/her decision based on the advantages and disadvantages of an unit, and I hope I provided some information for 50250.

50250 is truly amazing for its cost. It has been repeatly quoted by reviewers as the only air purifier which costs under $200 and actually purifies air. Given that it has a 250 CADR and is being sold for $165, the CADR/price ratio is an incredible 1.6 CADR/$. Whirlpool AP450 which Consumer Reports has rated as number one has a ~330 CADR and costs $250. AP450 has a 1.3 CADR/$. These ratios are the initial investment cost. You are buying the potential, not the payment for running them. In the long term, both units have similar operation cost as well. AP450 is quieter and is energy star certified using only 105 W at the highest speed. Assuming both purifier run at full speed continuously and the electricity cost is $0.1 per kWh (average in US), then 50250 and AP450 will have annual electricity costs of $150 and $92. The Whirlpool AP450 will save an annual $60 in electricity, but it will cost an annual $90-100 for HEPA filter replacement. Now, of course, Whirlpool AP450 is a more powerful unit. When considering the CADR per annual cost, then they are almost the same. 50250 has a 1.6 CADR/$ for the annual cost and AP450 has a 1.7 CADR/$. Both units are extremely good value products. Due to its quietness and low energy consumption, Whirlpool AP series is very suitable for people who suffer serious allergy and need to have the purifier operates continuously. The infamous Ionic Breeze has an estimated CADR of 20 and costs $350, a CADR/$ ratio of 0.06. In comparison, earth gravity alone has a cleaning power of 10 CADR in a large room. Moreover, Ionic Breeze outputs hazardous ozone in significant amount. Consumer reports and Air-purifier-america have issue warning in using them. Ask your doctor about inhaling ozone. I am providing a short link here:

http://www.msnbc.msn.com/id/7391185/

What amazes me is that you would think a low performance and potential health hazard appliance like Ionic Breeze will never sell. Yet, ionizing air purifiers constitutes a quarter of the air purifier sale. This is largely due to a smart and elusive advertisement campaign by Shaper Image and Oreck. At the same time, we consumers are also responsible for our own decisions, for which we based our judgments not on solid engineering and scientific specifications, but on fancy animated advertisements. This is why I strongly advocate taking advantage of the CADR information. Although it is not the only information which determine a purifier performance, it is certainly one of the most informative and most accessible value.

Finally, here is a link to AHAM for reader to research CADR value for various certified models:

http://207.140.180.12/dirsvc/aham.nsf/fraAirCln?OpenFrameset&pgm=Room%20%20Air%20Cleaners