Air Purifier Reviews

If you did no more than look at a photo you might not see any difference between the Winix FresHome P450, the P300, and the P150. In fact, while they house substantially similar technology, they offer equally substantial differences in specs and air purifying power.

Basic Specs

The basic case design of all three models – the Winix P450, the P300, and the P150 – is very much the same. That’s why it’s easy to be fooled by a photo. Each is a modified black-striped white rectangle with the panel on the top. But even in this area the differences become clear with a closer look.

• The P450 measures: 18.9″ wide x 25.6″ high x 11.8″ deep, while
• the P300 measures: 16.3″ wide x 21.7″ high x 10.4″ deep, and
• the P150 measures: 13.8″ wide x 18.5″ high x 9.1″ deep.

Those figures might give you the impression that the P150 and P300 are just scaled down versions of the P450, and in a way that’s right. After all, the weights go from:

• P450 = 19.40 lbs
• P300 = 13.95 lbs
• P150 = 11.15 lbs

But size (and weight) can be misleading. The difference in case volume and mass signal far more than just corner space required or ease of movement. Inside, where it counts, there are considerable differences in the three models.

Air Power, Coverage, and CADRs

Far more significant than mere size variations in the latest Winix air purifier models are the differences in how much air they can cleanse and how quickly. You see that right away in the air processing volume spec for each model, the CFM (cubic feet per meter) of air each one pumps. The figures vary for each model, naturally, depending on fan speed. Here they are:

• P450 – 50 (Quiet), 110 (Med), 175 (High), 290 (Turbo)
• P300 – 40 (Quiet), 90 (Med), 140 (High), 195 (Turbo)
• P150 – 25 (Quiet), 45 (Med), 70 (High), 99 (Turbo)

You can see at a glance that the differences are not trivial and far from gradual. Even on the lowest speed, for example, it jumps 60% from the P150 to the P300. Similarly, the jump from the P300 to the P450 at the highest speed is almost 50%.

Looked at that way, it’s not surprising then that the CADR (Clean Air Delivery Rate) numbers follow a similar pattern.

• P450 – 298 (Dust), 291 (Smoke), 343 (Pollen)
• P300 – 197 (Dust), 197 (Smoke), 214 (Pollen)
• P150 – 98 (Dust), 98 (Smoke), 103 (Pollen)

We can see here just how weak is the P150 in comparison to the other two FresHome models. That difference alone suggests that model really isn’t a worthwhile choice except possibly to purify the smallest of rooms. That hint is confirmed when we look at the area ratings for each model.

• P450 – 450 square feet (~21 ft x 21 ft)
• P300 – 300 square feet (~17 ft x 17 ft)
• P150 – 150 square feet (~12 ft x 12 ft)

Keep in mind, all ratings assume a standard ceiling height of 8 feet.

So, it might seem that the P150 would be a good choice for an ordinary home office, and it might well be. But bear in mind also that the actual area purified is usually a little less in real-world use than these ratings state. So, unless you have a very small room, and it can be kept purified continually with only very modest effort, the P150 simply isn’t going to have enough ‘oomph’ to do the job.

Well, at least it’s not hard to see where the Winix models get their names.

3-Stage Filtration Systems

Fortunately, despite their considerable and important differences, the technology each Winix model uses is still very much present in each one.

Stage 1 consists of a carbon pre-filter that helps remove the largest particles. That performs an important air cleansing function all its own – besides hair and lint, it filters out many household odors, for example. But it has an equally important purpose: to help the later stages work more efficiently.

Stage 2 is critical, since that one houses the True HEPA filter that makes all these air purifiers more than simply room fresheners. A True HEPA has to filter out at least 99.97% of particles no larger than 0.3 microns in size to qualify for the label. The special material and thousands of folds are what scour out pet dander, mold spores, and other airborne allergens.

Stage 3 is where the real differentiator of a Winix resides, though. This is the company’s proprietary PlasmaWave technology. It’s far more than just a marketing buzzword. For a more detailed explanation of how it works read the Winix P450 review.

Noise Levels

One thing I haven’t mentioned yet is noise level. That’s because it really doesn’t matter much here. True, the P150 puts out only 52 db on Turbo but the P450 is only moderately louder at 60 db. The P300 comes in at 55 db.

The numbers aren’t linear, so don’t be misled. You can definitely hear the P450 working when it’s running at the highest speed. But even this high-end model working as hard as it can is far from deafening. Keep it across the room from the couch near the TV and you probably won’t mind the noise.

Automation and Remote Control

Other aspects of the P150, P300, and P450 matter even less. They all use essentially the same sensors. All of them monitor the air flow and kick up to the higher speeds automatically, as needed. They all house the same controls to do that manually, if you prefer. They all offer the same fine visual indicators on the top panel.

There is one difference between the P150 and the P300 or P450 that might push some buyers away from the smallest unit, even aside from the room size/CADR issue. The P150 does not come with the remote control unit. How important that is will vary from one person to the next, of course, but for those who have difficulty getting around it can be a dealmaker.

Summary

A careful examination of the specs – and real-world use – of the Winix FresHome P150, P300, and P450 air purifiers shows they differ in much more than just size. Even discounting room area coverage, the P150 comes up short. That leaves the P300 and P450 as viable choices. There, it’s simply the usual tradeoff between price versus performance required. Let your budget and circumstances be your guide.

The Winix 5500 is a newer model than the Winix 5300. Does that make the 5300 obsolete? Should you just automatically purchase the newer model without bothering to look back? Let’s see…

Winix Inc has established a place in a very crowded home air purifier market and maintained it well over the past few years. They’ve done that by offering a lot of value for your money. Good examples are the Winix 5300 and the follow-on model, the 5500, both of which are still produced and supported by Winix.

Similarities

There’s a lot to like about both models.

For example, each offers essentially the same powerful fan that runs at four separate speeds: Quiet/Low, Medium, High, and Turbo. Each runs undetectably quiet on the lowest speed, a bare whisper at medium, and not really annoying at the high speed. Only in Turbo mode does the sound become (possibly) enough to interfere with conversation or hearing the TV easily. As a result of that fan and the filter system, both the 5300 and the 5500 have the same very respectable Clean Air Delivery Rates.

• 252 Pollen
• 248 Dust
• 236 Smoke

But those numbers do you little good unless you understand how CADRs are created. Without going into a lot of technical detail, they essentially measure how much air can be cleared in how much time.

The best thing to do if you don’t already own a home air purifier is compare those numbers to several other models of similar price. Comparing similarly priced models is key because you’ll see models, like the Blueair 503 for example, that list CADRs like 375 for all three categories. But it also costs double that of the Winix 5300 or 5500.

More Similarities – 3 Stage Purification System

The 5300 and 5500 have very similar filter systems. Each is a three stage system.

Stage 1 is a carbon filter. Carbon molecules in a mesh have a very large, chemically reactive surface area. That’s a fancy way of saying a lot of things stick to them and there are lots of places for them to stick. This section clears large dust particles, pet hair, and other room pollutants.

Winix filters offer less carbon than some other manufacturers model’s but they’re decent. In addition, they coat the filter with an antimicrobial compound to zap some microorganisms before they get to the HEPA filter in the next stage. That lengthens the life of the HEPA filter. However, some very sensitive buyers may object to the somewhat insecticide-like smell. It’s subtle, but some users do notice it.

Both models have this same advantage/drawback, so there’s nothing to distinguish them here except that the newer model has a slightly improved version. That is the 5500 filter’s odor is a little harder to detect.

Stage 2 is that previously mentioned HEPA filter and it hasn’t seen any significant change in filtration ability between the two models.

It’s not the equal of ones you’ll see in some high-end models like the awe-inspiring IQAir HealthPro Plus, but it’s good. On the other hand, that IQAir HyperHEPA model is three times or more the price of either Winix unit. The Winix HEPA certainly gets the job done, at least for all but the uber-sensitive. If you are, consider biting the bullet and buying something like the HealthPro.

Stage 3 in each model houses the company’s proprietary Plasmawave technology. That technology is Winix’s adaptation of something invented by Sharp and used in their Plasmacluster models. A plate inside generates positive and negative ions that are then expelled from the unit. They combine with airborne water molecules to produce hydroxyl radicals (negatively-charged OH molecules.

Those hydroxyls then break down VOCs (volatile organic compounds), such as those from cleaning products, gasoline exhaust fumes, and the like. They also zap airborne microorganisms – bacteria, viruses, mold spores, and the like – that can cause disease or generate allergic reactions.

There’s no major change between the two models because there was no need. That said, manufacturing quality has possibly improved a bit because there are many fewer complaints about the crackling noise from the ionizer. The 5300 has a noise that bothered some buyers; the 5500 seems to have improved on this.

Differences – Hepa Filter

The differences between the 5300, beyond improvements in quality control, are few and subtle, but may be important to some potential buyers.

First and foremost is the HEPA filter change between the two. The two filter the same but the HEPA filter in the 5500 is washable. That might not sound like much but it can be a big deal. HEPA filters are pricey and, despite what some manufacturers claim, do have to be changed sooner or later.

The one in the Winix 5300 was recommended to change about once per year. That will vary depending on room size and pollutant levels, of course, but it can only be stretched so far. By contrast, the HEPA in the 5500 can last the rated 2-3 years with proper care. Wash it well about every three months (when you change the carbon filter) and it will keep working at near-new capacity. That decreases your annual maintenance costs by two-thirds on this component.

One qualifier though. Washing, per se, doesn’t decrease the effectiveness. HEPA filters work as they do chiefly because of their physical characteristics, not any chemical coating. But no matter how well you wash them there will always be some material that doesn’t get removed and eventually the tiny ‘channels’ do get (at least partly) plugged.

More Differences – Remote Control

The other difference between both models is the remote control. The former lacked one but the 5500 has one. Whether that’s important to you is strictly a personal choice. Some owners barely use a remote for their home air purifier; others would suffer greatly without it.

The remote on the 5500 isn’t fancy but it is sufficient. It lets you set the fan speed manually and turn on/off the Plasmawave ionizer as well as the unit as a whole.

That said, both models are highly automatic. The sensor detects when to shift the fan speed. The sensor in the 5300 was an odor detector but the one in the 5500 is a particle detector. The difference is subtle and which works better is a matter of some controversy but both work well. So, whether you will feel the need for a remote control, even if you have limited movement ability, is an open question.

Summary

The Winix 5300 and the Winix 5500 are almost identical units. The differences are few and subtle. Both are fine mid-range home air purifiers. Which one is best for you, if either, only you can decide. Suffice to say, you can’t go wrong with either one if your room is not too large nor your nose, eyes, and lungs too sensitive. If they are, I recommend a higher end unit instead.

The Winix 9300 and 9500 home air purifiers are both fine units. In fact, they’re so similar in so many respects it can be hard to choose between them. Let’s take a closer look to see if there’s anything in the details to help decide between them…

Filter System – 5 Stages

The Winix 9300 model is slightly older than the 9500 but even then had pretty much the same fine filter system. This 5-stage system consists of:

Stage 1: Treated pre-filter. This removes large dust particles, pet hair, and much more from the airstream. That lets the filters later in line do a much better job of getting the small stuff. Apart from the usual improvements in quality control of later models, in this case slight to non-existent, there’s really no difference between the two here. Each models’ filter is coated with the same anti-microbial compound.

Stage 2: Washable HEPA filter. Unlike the Winix 5300 the HEPA filter in the 9300 and 9500 is washable. Here again, no difference. Both effectively remove smoke, mold spores, pollen, pet dander, and more.

Stage 3: Nano-silvered anti-microbial mesh filter. The buzzword “nano” aside (essentially meaningless here), this filter really does add value. Silver has the ability to kill a wide range of microorganisms. Here again though there’s no difference between the two models. Any 9300 sold today will carry the same filter as the newer 9500 – unless it happened to have been manufactured a year ago. That’s something to watch for in any case. Filters that sit unwrapped inside the unit will inevitably decay slightly over time. Their effectiveness is reduced by passively absorbing material from the air while still inside the box. It’s slower than ordinary use, but it does reduce the initial filter’s lifetime.

Stage 4: Washable advanced odor control (AOC) carbon filter. Differing from the Stage 1 filter, this is designed to remove smaller particles, including those tiny ones that come in the form of VOCs (volatile organic compounds). That reduces unpleasant odors but also improves room air by reducing noxious compounds. Those are a particular concern of chemically sensitive users – a large portion of the home air purifier market. But in this case, too, the 9300 carries exactly the same filter as the 9500.

Stage 5: PlasmaWave technology. This section holds Winix’s proprietary ionizer. Unlike older methods that use ozone, it generates positive and negative ions that combine with airborne water molecules to create OH ions (hydroxyl radicals). Those degrade airborne pollutants and kill many microorganisms that don’t make their way into the purifier. In this case, there is a slight difference between the two units. The design is the same in each case but Winix has improved on quality control. There are now many fewer buyers who complain about the low crackling noise the older unit use to sometimes emit during operation.

Operation, Performance, and Stats

At last we start to find some significant differences between both Winix air cleaners.

The Clean Air Delivery Rates between the two models show a notable difference. The CADR values for the 9300 are 142/138/145 (Dust/Smoke/Pollen) and 182/183/194 (Dust/Smoke/Pollen) for the 9500. Without going into a long, technical explanation it’s enough to say that the 9500 really outshines the 9300 in this important area. It clears more air faster.

That said, these numbers have to be approached with caution when comparing to other manufacturers’ models. Different brands list these numbers for two, four, or six air changes per hour. Winix lists theirs for two per hour. So, when you see a model with different numbers it may well be because they are measuring for six per hour. That’s good, an indication of a superior model. However, those typically cost two to three times as much. You get what you pay for.

Sometimes you get a little more than you pay for, however. The 9500 covers a larger area (up to 284 square feet) than the 9300 (up to 213 sq ft), and yet costs only a little more. It’s listed as 50 more on the official Winix site but sells for only about 10 more at Amazon, currently.

Part of the difference between the two is no doubt explained by the difference in size. The 9500 is a little bigger – 16.5″ W x 21.9″ H x 8.9″ D vs the 9300’s 13.8″ W x 18.5″ H x 9.1″ D. It’s also moderately heavier, 18.8 lbs (9500) vs 13.7 lbs (9300).

Offsetting that advantage marginally, the 9300 uses a little less electricity on the highest setting – 50 watts vs 70 watts (9500). That tiny difference in monthly running cost won’t sway many buyers, who will happily pay a few cents extra for much cleaner air. That extra juice no doubt drives the Turbo speed a little higher, contributing to those better CADR numbers.

Speaking of costs… when it comes to filter replacement, the 9500 is also a bit more expensive. The 9500 requires the Winix all-in-one filter kit #119110. The 9300 requires the Winix all-in-one filter kit #119010.

Sensors, Indicators, and Controls

The sensors and indicators in the two units are pretty much the same. The replace filter light tells you when to replace the filter unit – on average once every year and a half or so. Whether this is 12 months or 18 months or 2 years or something in between heavily depends on your air quality and hours of operation, of course.

Each houses fine odor and particle detectors, along with a light sensor to automatically downshift the fan speed when you turn off the room light. That sensor/switch also dims the panel lights to allow you to sleep more easily.

Each comes with a remote control to manually adjust the fan speed, if desired. You can also use it to turn off/on the ion generator or the whole unit. Each offers the same array of air quality lights, fan speed indicator, and so on.

Summary

The Winix 9300 is a fine, mid-range home air purifier. If you can pick one up at a steep discount you will probably be quite satisfied. However, for my money, the better numbers (translating into better air quality) on the Winix 9500 make the choice easy. Still, you may prefer a smaller, lighter unit even if it clears a slightly smaller room.

Alen air purifiers have a reputation for high filtration efficiency. That’s well demonstrated even in the relatively modest model, the Alen A375.

Basic Design & Specs

Curiously, the Alen A375 name seems not logical. The Alen A350 covers up to 750 square feet and products usually increase the spec as the product number increases. Yet, the A375 only covers up to 650 square feet. That’s backwards from the usual situation.

That said, there’s nothing funky about the spec here. Many air purifier models state a coverage figure and you have to hope it lives up to it. Alen has a well-earned reputation for understating their ratings. The A375 will definitely cover that area, provided you don’t have cathedral ceilings – and sometimes even then.

The case size is exactly the same as the A350. Here, that means a chassis measuring 17.5″ high x 18.5″ wide x 8.2″ deep. And, at 19 lbs, it weighs about the same. The A350 is 16 lbs.

5-Stage Filtration System

Here, too, the Alen A375 shows its family resemblance to its cousin. The filter system is a large tri-layered unit that can be replaced easily.

It incorporates first a pre-filter that, like most, has two primary purposes. One is to do as the name suggests: filter. Human and pet hair, large dust balls or particles, and the like get trapped here. The second important function is to ease the job done by the other layers, letting them function at peak ability.

The pre-filter is both washable and can be vacuumed. However, since the filter is a 3-in-1 style system, washing it could be a bit tricky. Getting the HEPA wet would definitely undercut its function, if not ruin it entirely. Luckily, vacuuming is generally good enough for this stage.

Just behind it (from the perspective of airflow direction) is the HEPA filter. It’s neither extraordinary nor flawed. Some filters of this type are the equivalent of hospital operating room units. Not even tiny viruses get through. This one does almost the standard duty – removing 98% of particles down to 0.3 microns.

I say “almost” intentionally… One reason you so often see that last figure listed with a HEPA filter is that it’s one of the official criteria. The DOE (US Department of Energy) standard requires removal of at least 99.97% of the particles that flow through to be a True HEPA. This one clearly doesn’t qualify on that score.

Still, experience shows that it does a good job of radically reducing home air pollutants. One reason is that – in one option (see below) – it’s silver coated, and therefore has some anti-bacterial ability.

By design, a HEPA doesn’t stop chemical odors and the like. Luckily, behind the HEPA-like filter is an Activated Carbon filter. It does get out the overwhelming majority of VOCs (household cleaning product vapors, for example). It also filters pet dander (the little protein molecules, part of the skin cells pets shed, responsible for allergies). And, it does an excellent job of removing cigarette smoke, pet urine odor, and other offensive chemical compounds.

The A375 does have a feature that puts it above the A350 in one respect: UV light. Inside the filter system there’s an additional component that shines ultraviolet light onto the passing airstream. That zaps a wide array of viruses, bacteria, and other nasty things before ejecting the air out the exhaust. If you’re sensitive, that can make a big difference.

Finally an Ionizer pumps out negative ions charging particles in the air making them larger and heavier. The larger size makes them easier to trap. Due to the larger weight they tend to float more readily to the floor or carpet, where they can be vacuumed up or sucked in by the air purifier. They also attach more readily to positively charged surfaces where they stick, harmlessly waiting to be wiped off.

Filter Options

As with the A350, though, this 3-in-1 filter style has a downside. It certainly could not be easier to change. You pop off the front panel, pull out the large rectangle, then pop in a new one. But it means you have to replace them all at the same time. Depending on the nature of your home environment, that may be forcing you to change, say, the Activated Carbon filter long before the HEPA is worn out. Or vice versa.

The implication of that is that you might have to spend more money for operating costs per year than necessary. It’s a tradeoff between simplicity and annual running expense, and only you can decide whether it’s worth it. At roughly 60-90 per filter (the same for the A350), it’s a coin toss in my mind.

There are actually several filter options from which to choose. The base level – the HEPA-Fresh Filter (BF25A), as Alen calls it –. It’s the plain vanilla of the bunch, but even in this elementary style it does a fine job.

The next step up is the HEPA-Silver Filter (BF25A-Silver). It has the ion coating that kills bacteria, described above. It’s also great at removing mold, cigarette odors, and similar allergens.

The most expensive version is the HEPA-Odor Cell Filter (BF25A-MP). It’s designed for getting every last spec of odor out of your home generated by cleaning products, smoke, and more. It does a superb job of that but, if replaced according to the company’s (quite reasonable) schedule of once every six months, the annual operating cost becomes pretty substantial.

Sensors, Controls, and Display

One reason the A375 can be as effective as it is, despite the relatively elementary filter system, is the sensor system. It monitors the air stream and detects pollutant levels. When that rises, the unit automatically increases the fan speed until the offending material is reduced below detectable level. If you want a practical demonstration, just light a cigarette in front of the air purifier. You’ll hear the higher speed kick in.

There’s a filter-change indicator light that works in conjunction with that system to alert you to the need. The display also provides easy-to-read indicators for fan speed, timer, and amount of dust and smell.

All the buttons provide positive feedback so there’s no need to wonder if they’ve been pressed, even if you’re having difficulty reading the panel. Hey, I don’t always have my glasses handy, either!

The controls follow a similar theme, being ultra-easy to use. The on/off switch is right up front near the top. Just above that is the fan speed control, timer and ionizer (de)activate button and indicator. Also, since the A375 has a UV light, there’s an additional UV Light (de)activate button and an indicator to show whether it’s on or off.

Summary

Alen A375 is currently selling for the same price as the A350 which covers a larger area. However, this model has with the UV light an extra filtration stage which will be a big value to some buyers and also comes with a remote. Either way you go, you’ll be getting a fine air purifier.

For an air purifier with such a mousey name, the Rabbit MinusA2 SPA-700a cleans air with a lion’s strength. Featuring superb CADR numbers, a customizable six-stage filter, and ease of operation on top of it all, it’s a real carnivore to dirty air.

Performance and Stats, Fearsome

CADR stands for Clean Air Delivery Rate. It’s an objective measure of how well an air purifier removes pollutants and potential allergens from your environment.

There are often different figures given for different types of problems. The SPA-700a has some impressive stats in all the areas. That is 193 for smoke, 201 for pollen and 200 for dust.

But those numbers can be fudged if they’re given for, say, a very small room. The SPA-700a’s numbers are for a 700 square foot room (with standard ceiling height of eight feet, two air changes per hour). That’s over 26ft by 26ft, very good.

Given the 47-187 CFM (cubic feet per minute) air volume processing stat, that isn’t too surprising. Air is drawn in a full 360 degrees around the front panel and expelled upward at the back of the unit. That ensures the device isn’t simply filtering the air swirling around itself but working on your room air at maximum efficiency.

But there’s more than a powerful fan at work here.

6-stage Customizable Filtration System, Elimination in Depth

The Rabbit Air MinusA2 has a customizable six-stage filtration system that is among the best available at any price.

In stage one the washable silvered pre-filter removes large particles, pet hair, dust, and even mold from the air. The silver also helps kill bacteria.

Next in stage two, there’s a medium filter to remove bacteria, pollen, smaller dust particles, and smaller mold spores.

That’s followed in stage three by Rabbit’s proprietary BioGS HEPA filter that eliminates fungus, more bacteria, dust mites, pollen, and other allergens. It even gets rid of certain household odors. Smaller dust particles don’t survive the journey and tobacco smoke, sulphur dioxide, and animal dander are eliminated.

Then in stage four there’s an additional custom filter that kills common household germs, along with still more mold, pet dander as well as many viruses.

It even tackles some pet odors, along with a range of potential toxins. Gasses from outgassing plastics get absorbed. Tobacco smoke is eliminated. Even VOCs (volatile organic compounds) like Formaldehyde are quashed.

Even better, you get to choose the custom filter that is best for your personal circumstances and environment. You can select either a Germ Defense, Pet Allergy, Toxin Absorber, or Odor Remover. All of them do a little of each, but different ones are designed to focus on your main concern.

The Germ Defense filter, for example, is especially adept at trapping airborne bacteria, mold spores, and particles that carry viruses through the air. For those with low immune resistance – babies, the elderly, or just the genetically unlucky – the ginkgo biloba extract on the surface helps reduce the amount of any influenza virus that might be present.

Next in line in stage five is the Activated Charcoal filter, which goes on to remove any remaining tobacco smoke in the air stream. It goes to work trapping additional household odors, including cooking odors. Make fish in the evening and by bedtime, the smell is gone. Clean your kitchen floor with ammonia-based cleaner in the morning and you won’t smell it by lunchtime.

In the final air-cleansing stage six a safe Ion Generator creates charged particles that are pushed out into the exhaust air. Those tend to attract all sorts of nasty particles in the air, which then fall to the floor or float to wall surfaces.

Behind those filters is that powerful direct current motor, a brushless design to ensure quiet operation and long life.

Maintenance

The pre-filter is a permanent filter and does not need to be replaced. Clean it once every month by running the brush attachment of your vacuum cleaner along the filter or by washing it gently with lukewarm water.

When the filter replacement indicator lights up it’s time to replace the other filters in the MinusA2. Depending on use and the air quality in your indoor environment, the life span of the filters will vary from 1 to 2 years.

Replacement filters can be bought in a handy all-in-one filter replacement kit – about 75 currently. Only make sure you know your custom filter! There’s a kit available for each of the 4 custom filters. The filters are interchangeable, too, so you can order more than one (or all) and swap them out from time to time. It’s ultra easy to do.

Cleaning the particle sensor with a damp cotton swab from time to time is no effort. A simple wipe with a clean cloth of the mood light lens, the air intake and outlet can be done when a visual inspection shows the need, which is not often, only about every 3-6 months. You won’t need more than 15 minutes or so to do everything.

Operation – Quiet, Easy, Low Cost, and Informative

The SPA-700a sips electricity. It consumes 47 watts at high speed, and only 7 watts at silent speed. Even at full blast, that’s less than a 60-watt light bulb. At average utility rates, that represents less than a couple of dollars per month to run the air purifier.

There are five separate speeds and the unit automatically selects the lowest speed needed, based on what it senses. You can set the speed manually, if you prefer, though. The noise levels are very modest for a unit that is so effective. Depending on the fan speed, it ranges from 20.8-45.6 dB. At the low end, you’d have a hard time hearing it operate from across the room. Even at the high end, you can comfortably listen to the TV with the MinusA2 going full tilt.

For all that power, it doesn’t way a ton: 19.4 lbs. That’s light enough to move around the house wherever you want, but hefty enough to prevent it tipping over at the lightest touch. That’s always handy for those who have cats who never tire of finding new things to rub against.

The stylish case with mood light is not huge, but not small either: 20″ high x 21.4″ wide x 7″ deep. It’s a bit on the wide side, but that shallow depth means you can place it near a wall, out of the way and not fear brushing against it or having to move around it. There’s even an optional wall-mount kit, if that’s your preference.

You can see at all times what the unit is doing, thanks to a number of indicator lights on the front panel. The lights are opposite the easy-to-understand buttons. The unit is easy to operate from across the room, too, thanks to the included remote control.

Summary

The Rabbit MinusA2 SPA-700a home air purifier is one of the most efficient and effective models on the market today. That’s chiefly thanks to excellent design and quality manufacture of its filtration system. But its operating characteristics are also highly impressive. It won’t roar when you use it, but you might want to give a joyful shout.

To these old ears the name Winix FresHome P450 sounds more like a classic airplane than a contemporary air purifier. They do have one thing in common, though. They both achieve their purpose with superb technology.

Basic Specs

The Winix P450 is one of the latest models from this relatively new air purifier manufacturer. Here, Winix shows they’ve learned a lot very quickly.

Those lessons learned start with a slick, stylish case that makes for good furniture along with good function. The housing measures 18.9″ wide x 25.6″ high x 11.8″ deep, making this rectangular model possibly a bit large for those who are space constrained.

For everyone else, it’s perfect. It weighs 18.7 lbs, making it among the lighter high-power, moderate-to-large-space covering models around. The only potential problem with the design here is the location of the air intake; it’s on the side of the unit. That can work great if you put it in a place that has adequate room.

If you have to place it too near a wall, though, it can hinder the ease of air flow. Making the motor work too hard to draw in dirty air will necessarily reduce the efficiency of the purifier. On the upside, the front vent pushes fresh air directly into the room.

Power, CADR, Coverage Area and Noise Levels

Inside that case it packs both a lot of air-pushing power and air-cleansing ability. Four different fan speeds drive air at CFM (Cubic Feet per minute) rates of:

• Quiet: 50
• Medium: 110
• High: 175
• Turbo: 290

The results are CADR (Clean Air Delivery Rates) that are quite good, among the highest around at this price point.

• 343 Pollen
• 298 Dust
• 291 Smoke

Those numbers are on the high side of what the company has offered on models in the past, making this among the most powerful models it has offered to date.

Those levels will take care of the rated room area – up to 450 square feet – with room to spare, so to speak. For the math challenged, that’s a room a little over 21 feet on a side. So, even those with substantial living rooms can enjoy clean air all day and night. One qualification, though. Those CADR and coverage numbers invariably assume a standard ceiling height – 8 feet.

Fortunately, for all that air volume and cleansing ability, you don’t have to suffer with an unacceptable noise level from the P450. The volume is noticeable when running at Turbo (60 db), but just a whisper when on Low (27 db). Since the highest speed is really only necessary to clear out high concentrations, usually for only a short time, the sound intensity is unlikely to bother most buyers.

3-Stage Filter and Cleaning System

The Winix P450 can achieve that air quality because like the company’s other models it houses their superb filtration system. Even with only a 3-Stage system, while other models/manufacturers boast four or even sometimes seven, it works well due to a unique design.

Stage 1 isn’t anything dazzling. It consists of a carbon pre-filter that is much like the next guy’s. It works well by trapping the large particles that enter the unit, including cigarette smoke, cooking odors, and more. But that’s not the truly impressive part.

Similarly, Stage 2 is very good but not wow-inducing. It features a True HEPA filter that gets out 99.97% of particles down to 0.3 micron in size. That’s pretty standard these days and, in fact, those numbers are the bare minimum required to qualify legally for the “True HEPA” designation. The filter gets out small particles and even some larger bacteria, along with pet dander, mold spores, and more.

But Stage 3 is where a Winix air purifier comes into its own. This section features the company’s proprietary PlasmaWave technology. Far more than a buzzword, it merits a longer discussion.

A plate inside the unit generates positive and negative ions that are then expelled from the case. They combine with airborne water molecules to produce hydroxyl radicals (negatively-charged OH molecules).

Those hydroxyls are harmless to you (in the low concentration produced here) but effectively break down many common airborne lung, nose, and eye irritants. They also kill a variety of harmful microorganisms. That’s especially helpful to cleanse any air that doesn’t enter the unit and get filtered before it enters you.

That explanation may be interesting to you or it might put you to sleep, but one thing anyone who uses the P450 can agree on is this: PlasmaWave technology works – really, really well. It zaps disease-causing microorganisms, causes particles to become heavy enough to drop to the ground (and out of the airstream), and keeps the air fresher feeling overall.

The net result of all three stages is to produce air that is both physically healthier and also more pleasant.

Automation and Remote Control

A set of sensors inside monitor the quality of the air passing through the unit in order to automatically adjust the fan speed. Or, you can set it manually if you prefer. One automation feature is likely to be truly welcomed by those sensitive to noise; when you dim the room lights the fan automatically goes into quiet mode.

Also, the P450 comes with a small handheld unit that lets you adjust the settings from across the room. Since there’s so much automation built into regular use – the sensors, auto-adjusting fan speeds, and more – it’s not likely to be used much by most buyers. But for those who have difficulty getting around it can really be a godsend.

Summary

It would be difficult to choose one single air purifier that is the best model of any available, taking all factors (including price) into account. But given its quality, feature set, and mid-range price, the