It’s difficult to find a truly impressive home air purifier at a mid-range price. Often, the truly sensitive have to swallow hard and layout a 1000 to get something that will effectively tackle room air. The Winix 9500 manages to surprise and delight by doing that for less than 300.
Filter System – 5 Stages
One of the key aspects of any good air purifier is the filter system, obviously. The 9500 offers a 5-stage design that is much more than just a number. Each stage does an important job and does it well.
Stage 1 is a pre-filter that extracts the largest particles – dust, pet hair, and the like – from the air stream. You can see firsthand that it’s doing the job by letting the unit run for a month or so then opening up the unit for cleaning. Unless you live in an electronics manufacturer’s cleanroom you’ll easily spot a lot of material to vacuum off the filter.
That pre-filter is washable for even better removal of material. It’s also treated with an antibacterial compound that reduces the microorganisms the later stages have to deal with. However, some especially sensitive people might dislike the odor so this can be a mixed blessing.
Stage 2 offers a HEPA filter that is as good as any around in the mid-range niche. Some truly high-end machines have a HEPA filter that could be used on the space shuttle :). This one doesn’t reach that standard but neither does it need to in order to be effective. It, too, is washable, reducing annual maintenance costs.
Stage 3 houses a mesh that’s coated with silver, which has anti-microbial properties. It can only kill organisms that come in contact with it, so it’s not going to remove all potential disease-causing or allergy-stimulating creatures from your home. But it does help reduce their number considerably.
The washable advanced odor control (AOC) carbon filter in stage 4 goes beyond removing dust, dander, pollen, and other allergens. The carbon it contains removes a lot of VOCs (Volatile Organic Compounds), one of the chief villains that cause chemically sensitive people to suffer.
Neither it nor the purifier as a whole are designed to completely remove all paint fumes and the like after an indoor home improvement project. No mid-range unit is going to do that. But it can effectively remove vapors produced from household cleaning products, along with other common chemicals in low concentrations.
Stage 5 contains the company’s proprietary ion generator, which they call PlasmaWave technology. That fancy name might stretch the definition a bit (ask a physicist) but it’s not a con job.
The unit generates positive and negative ions that enter the air and react with airborne water molecules. That creates negatively-charged OH molecules (hydroxyl radicals). Those hydroxyls then break down indoor pollutants and also kill some of the airborne bacteria, viruses, and more.
Unlike older technology, still in use in some home air purifiers, it produces no ozone (O3 molecules). While the health hazards of indoor, ion generator-produced ozone was sometimes overstated, this method is safer as well as more effective.
Performance and Stats
That excellent filtration system would be ineffective, however, without a good fan and efficient air flow. Fortunately, the design of the Winix 9500 offers all that in abundance.
The unit can push a fair amount of air, thanks to a robust 4-speed motor (Low, Medium, High, Turbo) and an efficient case design (in through the bottom and sides, out through the top).
Surprisingly, the CADR numbers are considerably lower than their less expensive model, the Winix 5500. They are:
- 194 Pollen
- 182 Dust
- 183 Smoke
about 50% lower than the 5500’s ratings. That’s a bit mysterious and there’s reason to wonder if the numbers (or the 5500 model’s) are misstated. However, CADR ratings require interpretation. Ideally, they’re listed for six full air changes per hour rather than the two or four of some manufacturers/models. There’s no way to know in this case.
It’s also odd that they state the 9500 covers up to a maximum of 284 square feet when the 5500 is listed as covering 350 sq feet. It may be that they’re more conservative here or that the extra filters reduce the amount of air it can clear.
Whatever the official numbers say, real-world experience shows that the 9500 does a fine job of clearing a room’s air. Light a cigarette a few feet from the unit, then let it burn for a minute. The 9500 will automatically increase the fan speed to Turbo and clear the smoke in a few minutes to an undetectable level.
Sensors, Indicators, and Controls
One reason the 9500 can do that is the superior set of sensors in this model. Going well beyond the quite-good 5500, this model houses dust and light sensors along with the odor sensor found in the lower-end version.
Those sensors measure particulate concentration in the air stream and adjust the fan speed accordingly. A hint of paint thinner or household cleaning spray in the air kicks the fan up into high. When the unit senses those compounds have dropped below a pre-set threshold, it downshifts into low again for quieter, lower-cost operation.
There is also an Auto-Sleep mode that will lower the fan speed when the room lights are dimmed. You can put it into that mode manually, too.
On the lowest setting, the unit consumes only about 6 watts so you’ll see practically no increase on the electric bill. Even on Turbo the 9500 sucks up only 70 watts so it draws less than the average lightbulb. The unit goes still further by providing a programmable timer to allow you to set it to run for only 1, 4, or 8 hours if you like.
Many of the settings can be set using the supplied remote control.
Conclusion
The Winix 9500 is pretty quiet (except on Turbo), handles a good-sized room, and barely sips electricity while offering fully automated operation. To this reviewer, that’s impressive.
True, it lacks some features of high-end home air purifiers. It doesn’t have a UV germicidal light or an electrostatic filter for example. But unless you are uber-sensitive and require a unit that zaps or removes every last compound, organism, and allergen, you will probably never notice the difference.