Nukit Tempest FAQ

Frequently Asked Questions

How many CADR is the Nukit Tempest?

It really depends on how you configure it. Which fans, filters and fan guards you use make a significant difference. It’s estimated to have a 2.5 micron CADR of about 300CFM (509 m3/hr) but we will be testing different configurations and publishing the results soon. Remember when comparing the Tempest to other air purifiers most measure CADR on their highest settings- which result in noise levels that are unsustainable.

Are you planning to make a larger or higher CADR version of the Nukit Tempest?

Not unless there’s a real demand. For larger rooms, multiple air purifiers spread throughout the room are much better at mitigating near field transmissions, with less noise than one very large unit. Also, one large 600 CADR filter wouldn't cost much less to manufacture and ship than two 300 CADR filters, so it's not even more economical.

Do you sell pre-built versions of your kit?

Not at the moment - although we are open to other people building and selling them. There are a couple of reasons for this. There are popular DIY air purifiers consisting of several large furnace filters attached to a standard box fan. They are easy to build, fun to decorate, and have become a common STEAM project in schools.

Photo courtesy of "Festucarubra"

When kids do something with their own hands, they have a stake in the outcome. They are invested. In many Asian countries, students are involved in “School Cleaning". There are few or no janitors. They clean the classrooms themselves, so they are invested in keeping those spaces clean and tidy. Clean air is as important as clean water, clean hands, or clean rooms - and one of the best ways to teach this to kids is to involve them in the process of creating clean air. When you build the air purifier, having it removed or disabled is something you take personally.

"School Cleaning" in a Chinese classroom

The second reason is that most air purifiers on the market today have a fairly short life span. This is by design, they follow the disposable razor business model - they have attractive, futuristic shapes but are made from cheap plastic and low-grade motors. They are cheap to buy, but use expensive proprietary filters. Most become e-waste within 2-3 years as their motors and bearings wear out. If you want to buy replacement parts - good luck. A few years into the pandemic, we're already seeing dumpsters full of expensive air purifiers bought early as they wear out or become too expensive to maintain due to budget concerns.

Photo courtesy of Christopher Vanderpool

The Nukit Tempest, on the other hand, is designed to be a “Buy It For Life" device. It's cheap to run and it's repairable. This puts the hourly cost of operation per cubic meter of clean air delivered well below almost any indoor air purifier sold today. You can reasonably expect decades of service life. Standard fan sizes used throughout industry in critical equipment that requires maintenance are unlikely to disappear, and countless HVAC systems are not going to be completely gutted any time soon, so standard size filters that have been available for decades will undoubtedly be available for many more.

The Nukit Tempest is not a plastic slab that you throw away and buy another in an endless cycle of consumption and waste. In 5 or 6 years when a fan starts rattling, you grab a screwdriver, swap that fan out, and it’s all as good as new. But the best way to know how to do that when the time comes is if you put it together in the first place.

So unless you’re the sort of person who fixes squeaky hinges by buying a new door instead of grabbing a can of 3-in-1, roll up your sleeves, grab a kid if you have one handy as an assistant, and put together the kit😉

Why is there no power switch or speed control?

There is a 19mm port that could accommodate a standard size switch or knob - but we wouldn't recommend it. One of the biggest problems with using indoor air quality devices in public spaces is the absolutely inexplicable urge of the public to turn these devices off or down to the point where they are ineffective. Schools and businesses are now full of expensive air purifiers sitting unused and unconnected in corners.

Turning a filter down because it's too loud is a design problem. Noise level is something that should be addressed in the initial design itself. Ideally, an air filtration device should not be able to produce noise at a level inappropriate for the space in which it is placed.

While the standard Nukit Tempest can't be turned off or down by design, that still leaves the problem of people with an inexplicable need to unplug air purifiers. To address this issue, we are about to release an add-on board that will sound an alarm when the unit is unplugged and power is lost, and will continue to sound the alarm until it is plugged back in. This is a bit of an extreme measure, but it has proven to be effective in preventing tampering.

Why don’t you include fans, fan guards, or a power supply?

When it comes to in-room air purifiers, to paraphrase the joke, "You can have cheap, quiet, or effective - pick any two". You can have air purifiers with inexpensive, fairly quiet fans - but they are less powerful and will result in a lower CADR. You can have powerful but inexpensive fans - and you will have a high CADR, but also a higher noise level. You can have powerful, quiet fans - but they will be very expensive. This may make sense for an executive conference room, but for a dental office with multiple treatment rooms, noise is hardly an issue given the sound of drills, and a high CADR is a top priority. That said, the PC fans suggested for use with the Nukit Tempest offer a very good balance and are suitable for most applications.

The same goes for fan guards - a mesh fan guard costs a bit more and will slightly lower the CADR, but it is still a very good idea if you have young children with vivid imaginations who like to endanger their heroic Lego and action figures by lowering them into spinning fan blades. But in a childless office environment, there is no need to sacrifice effectiveness, and metal grilles are perfectly adequate.

We offer an internal Mean Well power supply for locations with specific code requirements. It’s better to let the customer get what they want than have more e-waste and higher costs by bundling what they don’t.

In short, if you’re going to assemble a kit anyway, you get the best value by using those parts that fit your use case exactly- not a mass-manufactured compromise, either too expensive, or too weak, or too noisy. If your use case changes in a few years- no problem. Just swap those parts out, and you’ll have whatever is best suited for your current circumstances.

Will the included mesh side panels reduce effectiveness?

As mentioned above, one of the unfortunate things we've discovered about indoor air quality is the level of resistance many members of the public often have to it. Whether it's a reminder of a risk they'd rather not think about, noise, or concerns about power consumption, many of the expensive air treatment devices purchased and installed in recent years have gone unused and are now sitting in corners collecting dust. Purchasing indoor air purifiers has proven to be less of a problem than getting people to accept these machines and not turn them off or unplug them. The best CADR money can buy won't help if the machine is so loud or obtrusive that people object and turn it off - as they seem to do at an alarming rate.

For this reason, the Nukit Tempest is designed to pass for a personal computer or network server - something most people know not to unplug. While the mesh side grills slightly reduce CADR, they make the device much more stealthy and "PC-like". If you have a space like a dentist's office where CADR is a top priority and the device is unlikely to be disabled, leaving the mesh side panels off is perfectly reasonable. In other locations, however, it may be advisable to use them to maintain a low profile.

In short, with the mesh side panels off, it's more obvious that the Nukit Tempest is an air purifier, so it's more likely to be disabled - and a disabled air purifier is completely ineffective. So the answer to the question "Do the mesh side panels reduce effectiveness" really depends on where you use it. It will reduce the CADR somewhat, but it may be more effective because it discourages tampering.

I see a small gap in the case; won't that air leakage reduce effectiveness?

Intuitively it seems like it should- after all, a good fit is essential for masks to be effective. But masks need to remove as many particles as possible in one pass- before you breathe them in. Air purifiers have to remove as many particles as they can per minute, and unlike a mask, they have multiple passes to do it. A good PAPR like the 3M Versaflo has almost no internal leakage and can remove almost all particles at or above 0.3 microns in a single pass- but using enough of them to filter room air would cost a fortune compared to using air purifiers that would get you to the same CADR in the same amount of time in multiple passes.

For indoor air quality, removing particles with multiple high-volume passes tends to get you cleaner air, for less money than trying to remove everything with a single low-volume pass. If my friend has a small net and I have a large net with a little hole in it, and we both paid the same amount for our nets, and we both are hauling fish out of the water- sure I’m going to lose a few fish each time, but I’m still going to take more fish out of the water.

Large gaps will reduce internal pressure to the point where efficiency suffers, but very small gaps, like you might see on the Nukit Tempest, are not really a problem because the static resistance of the filter is usually the bottleneck, not a very small drop in internal pressure. If it really bothers you, you can seal them with Blu-Tack.