Nukit Tempest Pro FAQ
Frequently Asked Questions
Is the Nukit Tempest Pro a HEPA filter?
PC fan air purifiers like the Tempest Series use MERV 13 filters to achieve the same effect in multiple high-volume passes as HEPA filters do in a single low-volume pass. This science is well tested and explained here:
Clean Air Delivery Rate Is All That Matters!
Data and citations here:
Long story short- HEPA has become mostly about marketing; what you want is high CADR at low dB levels.
I found another air purifier with higher CADR...
Great- but at what sound level? Under 39dBA for the same yearly operating cost?
People have learned to buy air purifiers based on CADR, which is excellent. So manufacturers have learned to maximize that number- which they should.
The problem is that the best way to easily get high CADR is with powerful, cheap, and so usually noisy, fans. This means that the maximum CADR for which the air purifier is sold, it is almost never actually used at because it's too loud to tolerate for more than a few minutes. If you own an air purifier already, do you leave it running 24/7 on max power?
People assume that a high CADR air purifier must also deliver a high CADR at lower settings, when this often not the case. Fan blade geometry and speed are optimized to perform best at max power. As soon as you turn it down, performance drops sharply. So if you buy high CADR to turn on maximum power occasionally, 90% of the time you are running it, it will be offering very poor performance because that's not the speed it's optimized to operate at. A purifier designed to have an acceptable sound level at maximum power, will always be operating at maximum efficiency.
One of the most important lessons we learned at the start of the pandemic, when many of us began buying and building DIY filters, is that loud air purifiers are seldom actually left on. If you have a loud air purifier, you have zero air purifiers- because it won't be left on.
We designed the Tempest Pro to have a high level of Usable CADR- quiet CADR that won't disturb people and cause them to turn the machine off.
≤ 35 dBA is the standard for classroom noise*. The Tempest Pro is just a little above that for home and office use and can be turned down slightly for bedroom and classroom use. On its maximum setting, it's one of the quietest air purifiers available. If you really want a higher CADR, you can substitute Arctic P14 PWM fans and get 248-299 CFM- but at a higher sound level.
*Sound level standards:
Remember- intolerably loud CADR, is CADR you can't use. Only CADR you can live with counts.
What is the advantage of PWM Fan Speed Control?
PWM speed control is more expensive, but it enables higher CADR at lower noise levels compared to voltage-based speed control, so it's what we include. The Nukit PWM speed controller can be mounted in three ways:
Inside the enclosure
The included magnetic mount allows the speed controller to be attached anywhere inside the case. Ideal for setting the Tempest Pro to an optimal CADR and noise level, then closing it up to prevent visitors from turning the power down to ineffective levels.
We strongly recommend this configuration, particularly for offices and public places where air purifiers are often tampered with for various reasons.
Through-hole
The knob goes through the 19mm accessory hole with the PWM speed controller attached to the inside of the case. Accessible, but low-profile and unobtrusive. Best for homes with responsible users who are conscientious about keeping the unit on at the highest level possible.
External
The speed controller attaches outside the case with the magnetic mount, its PWM cables passing through the 19mm accessory hole and held in place with the included silicone plug. Fully accessible for precise control. Best for sole occupants and for determining optimal power levels before sealing the controller inside.
Why is there no power switch, and why are you so insistent about hiding the speed control?
There is a 19mm accessory port that can accommodate a power switch - but we don't recommend it. Here's why- one of the biggest problems with using indoor air quality devices in public spaces is the public's inexplicable tendency to turn these devices off or down to the point where they become ineffective. Schools and businesses are now full of expensive air purifiers sitting unused and unconnected in corners.
Turning the power level of 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 produce noise at a level inappropriate for the space in which it is placed- then there is no need to ever adjust it.
With the Tempest Pro, we recommend using the included PWM speed controller to set the fans to a noise and CADR level suitable for that space during assembly, then closing it up and leaving it at that setting.
No matter how certain people are that they will be diligent about making regular adjustments, accessible speed controls in the real world seem to inevitably result in air purifiers either being turned off, or left at ineffective levels for months at a time.
As it stands, the most effective air purifier is the one that goes unnoticed, and when noticed, it cannot be easily tampered with.
Why does the Tempest Pro cost so much more than the Tempest?
Extra parts (fans, etc) but mostly weight! Both units are steel but the Tempest Pro is a lot larger with parts the Original does not have like the heavy wall & ceiling mount so weighs a lot more. Part of the transport costs are rolled into the base price, then that is compounded by higher tariffs. It really is a buy-it-for-life product, so the long-term costs of ownership and operation are much less than other air purifiers.
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 were already seeing dumpsters full of expensive air purifiers that had been purchased early, then disposed of as they wore out or became too expensive to maintain due to budget concerns.
Photo courtesy of Christopher Vanderpool
The Nukit Tempest series, on the other hand, is designed to be “Buy It For Life" devices. They are cheap to run and repairable with just a screwdriver and easy-to-find parts. This puts the long-term hourly cost of operation per cubic meter of clean air delivered well below almost any indoor air purifier sold today. You can reasonably expect a service life of decades.
Standard 140mm size PC fans used worldwide for critical equipment that requires maintenance are unlikely to disappear, and countless HVAC systems in hundreds of thousands of buildings are not going to be completely gutted any time soon, so the standard size filters that they have been using for decades- and that the Tempests also use, will undoubtedly be available for many more.
A 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. However, the best way to know how to do that when the time comes is to put it together yourself 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 oil- roll up your sleeves, grab a kid if you have one handy as an assistant, and put together a kit that will last a lifetime😉
Can I use a carbon impregnated filter for VOCs and odors?
We recommend standard 3M Filtrete, 20”x25”x1”, MPR 1900, MERV 13 filters. While there are similar filters with a carbon layer, the amount of carbon contained is insufficient to last for more than a few weeks. To be effective, you need at least 2 pounds (or almost a kilogram) of activated carbon. HouseFresh talks about it here.
Many of our customers have had great success with placing bags of activated charcoal inside their Tempest, along the bottom of the enclosure. These are very inexpensive, easy to reactivate (just place the bags in the sun for a few hours), and have proven extremely effective (if a little low-tech).
Will the included mesh side panels reduce effectiveness?
Slightly. 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 purifiers 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 actually getting people to accept the presence of these machines and not turn them off or unplug them. The best CADR money can buy won't help if the machine is so obtrusive that people object and turn it off - as they seem to do at an alarming rate.
For this reason, the Nukit Tempest series is designed to pass for personal computers or network servers - something most people know not to unplug. While the mesh side grills slightly reduce CADR, they make the device much more discreet 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 and avoid notice.
If you have the Tempest Pro wall or ceiling mounted, you can compromise by only using the outside-facing mesh panel, as the inside one can't be seen.
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 them. 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 must remove as many particles as possible per minute, and unlike a mask, they have multiple passes to achieve this.
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 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.
Very large gaps will reduce internal pressure to the point where efficiency suffers, but small gaps, like you might see on your 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.