Ionisers Explained: Why We Don’t Use Them (and Why Some Brands Do)

  Ionisers in air purifiers are often marketed as a bonus feature, but they mostly boost lab test numbers rather than actually cleaning your air. Ionisers charge particles so they stick to surfaces instead of being trapped in a HEPA filter. They can artificially increase CADR scores, and turning them off usually means lower real-world performance. A test on a Blueair unit found 20–50% of CADR came from the ioniser, not the filter. Ionisers can create ozone and chemical byproducts, and increase visible dust on surfaces. HEPA-only purifiers with decent airflow are simpler, safer and more transparent. 1. The benefits ionisers claim to offer Manufacturers usually claim ionisers: “Freshen the air” “Neutralise pollutants” “Boost cleaning efficiency” “Tackle ultra-fine particles too small for filters” “Break down odours and VOCs” On paper it sounds impressive. In reality: Ionisers don’t capture particles, they just charge them so they fall onto surfaces. They don’t improve actual filtration. And the air isn’t cleaner, your surfaces just get dustier. What ionisers actually do is charge particles in the air so they stick to nearby surfaces (walls, furniture, your lungs, your skin) instead of staying airborne. 2. How ionisers inflate CADR scores without really cleaning the air This is a key reason manufacturers love ionisers. CADR tests (Clean Air Delivery Rate) measure how fast particle levels drop in a sealed test chamber. The test doesn’t care whether those particles were: Actually filtered through a HEPA filter, or Simply knocked out of the air and stuck to surfaces by the ioniser Ionisers make particles drop faster, so the CADR number gets a boost - even though the purifier hasn’t genuinely “cleaned” more air. 🚨 Important:Most purifiers let you switch off the ioniser, but when you do, the CADR is often much lower than advertised. Manufacturers almost never publish the “ioniser off” CADR, so consumers are left thinking they’re buying a higher-performing unit than they actually are. A third-party test of a Blueair purifier shows how big this gap can be. With the ioniser turned off, CADR dropped dramatically across particle sizes. Smoke fell by 44%, dust by 19%, and pollen by 53%. The researchers concluded that around 20–50% of the purifier’s measured CADR came from the ioniser, not the actual filter. Read the full report here This is why brands love ionisers: Very low manufacturing cost Bumps the test numbers Helps justify a higher price No obligation to reveal the real, filter-only performance 3. A very cheap add-on that creates a higher-priced product Ioniser modules cost very little to manufacture. Far less than a better motor, fan, or filter. But because they artificially boost test numbers, brands often use them to justify: Bigger “high-performance” claims A higher RRP Positioning the unit as “premium” or “advanced” It’s a low-cost trick with a high-margin payoff. This is one reason so many mass-market purifiers include ionisers by default: not because they’re effective, but because they sound impressive and help the spec sheet stand out. 4. The word ‘ioniser’ often goes by different names Because many people are wary of ionisers (especially due to ozone concerns), companies often rebrand them under different names, including: “Plasma ion technology” “Plasmacluster” / “PlasmaWave” “Negative ion generator” “Cold plasma” “Hypoallergenic mode” “Nanoe” “Streamer" Different name, same mechanism: charging particles so they stick to surfaces. If a purifier advertises “ionic”, “plasma”, or “active air cleaning”, always double-check what it actually does. 5. They can increase visible dust, not reduce it Because ionisers push particles out of the air and onto surfaces, you often end up with: More dust settling on furniture Black streaking on walls (common with bipolar/“plasma” units overseas) Dust build-up inside the purifier housing A proper HEPA purifier captures dust inside the filter and removes it from circulation entirely. 6. Health side: ozone, byproducts, and why NZ schools were told to avoid ionisers Ionisers can generate small amounts of ozone as a by-product. Even when the levels are low, ozone is a highly reactive gas. Indoors, it can react with everyday chemicals, things like cleaning products, perfumes, building materials and even the natural oils on skin and surfaces to create new VOCs and aldehydes. So instead of reducing chemical pollution, ionisers can unintentionally add extra byproducts to your indoor air. This is one reason many public health and education bodies advise against ionisation devices. In New Zealand, the Ministry of Education’s official ventilation guidance was very clear by requesting schools do not purchase air purifiers with ionisers for classrooms. “We recommend air cleaners with high-efficiency HEPA filters, and do not use emerging technologies that emit any substances into the air (for example ionisers, plasma discharge, ozone generators, photocatalytic oxidation or hydrogen peroxide).” That’s a strong signal that ionisers and other “active” purifier technologies aren’t yet considered safe or reliable in real-world indoor environments. 7. So why doesn’t Snap Air sell ioniser purifiers? Because they don’t fit what we stand for: No gimmicks to inflate CADR No cheap “add-on” used to justify a higher price No hidden chemistry that could add byproducts to your air All the purifiers we sell stick to transparent, well-understood tech: High airflow Proper HEPA filters Carbon filters where odours/VOCs genuinely need to be reduced No ionisers, no plasma marketing, no mystery “active” systems When you see a CADR figure on our site, it’s coming from actual filtered airflow, not ions knocking particles onto your walls. 8. What to look for instead of ionisers If you’re shopping around and want genuinely cleaner air, focus on: HEPA filter: H12 or H13 for particles CADR / airflow: big enough for your room size and target air changes per hour Carbon filter: only if you need help with smells or VOCs Noise levels: so you can actually run it at an effective speed Honest specs: no vague “plasma”, “ionic shield” or “active molecular” language You don’t need fancy-sounding tech to get clean air. You just need: A decent fan + a good HEPA filter + enough airflow for your space. If you want to skip the ioniser maze, every purifier we stock is ioniser-free and HEPA-based only, so the performance you see on the spec sheet is what you actually get in your room.

Dust is one of those things every home has, and no air purifier can make it magically disappear. But a good purifier can make a noticeable difference - as long as expectations are realistic and you choose the right machine. Here’s a clearer look at how dust actually works, and what an air purifier helps with. Dust isn’t just one thing Dust is a mix of all sorts of stuff: dead skin cells, fibres, soil, pollen and plenty more. Importantly, most of the dust you actually see tends to be the heavier bits. This is the kind that settle quickly on shelves, floors and TV stands. Meanwhile, the smaller, lighter particles (the PM2.5 type) stay airborne longer. These are the ones commonly linked to allergies and respiratory issues, and they’re exactly what HEPA purifiers are designed to capture. So… can an air purifier get rid of dust? Yes - but only the dust that reaches it. If dust is floating in the air long enough to be drawn into the purifier, it’ll be captured by the HEPA filter. That part works extremely well. But visible dust that has already settled? That’s where expectations need to be realistic. Air purifiers don’t vacuum floors or wipe surfaces. The heavier particles simply don’t stay airborne long enough to make their way into the purifier before they fall. You’ll still need to dust, but usually less often Many people find that while a purifier won’t eliminate visible dust, it can slow down how quickly surfaces get dusty, especially if: It runs continuously You run it on a higher speed when cleaning or vacuuming (which kicks particles into the air) The purifier has a high CADR (Clean Air Delivery Rate) A higher CADR simply means the purifier moves more air through the filter each minute, so it has a better chance of catching particles before they settle. What about ionisers and “negative ions”? You’ll see many purifiers advertise ionisers or “negative ion” features. While they can make particles clump together, this often leads to more dust settling on surfaces, not less. They don’t actually remove the dust from your home, they just make it fall out of the air faster. They also don’t replace a proper HEPA filter, which is what actually captures particles. For most people, especially those dealing with allergies or wanting less dust in the air, a HEPA-based purifier (without ionisers) is the better choice. It cleans the air without creating extra surface dust or producing ozone. HEPA filters catch the fine stuff extremely well The main win with a purifier isn’t reducing visible dust - it’s reducing the fine, invisible particles that you breathe in. These are the ones that can cause irritation, asthma symptoms and allergies. If fine dust is the issue (particularly PM2.5), you’ll get a very noticeable difference with a properly sized purifier. What about “dusty rooms” or homes that get dusty very fast? A purifier can help, but it won't fix the root cause. Common sources include: Open windows on windy days Construction or farm activity nearby Indoor renovations Leaks in older homes Dust blown from heat pumps or ventilation systems Carpet shedding A purifier improves what’s airborne, but it can’t stop dust being created or stirred up. The bottom line A good HEPA air purifier won’t eliminate dust, and it’s better to be upfront about that. What it will do is: Capture fine particles extremely effectively Reduce how much dust stays airborne Slow down how quickly surfaces get dusty (in most cases) Significantly improve overall air quality If you’re choosing a purifier specifically for dust, the most important spec to look at is CADR. A higher CADR means more airflow, and more airflow means more chances to catch those particles before they settle. And of course, if dust is bothering you, a quick vacuuming session right before switching the purifier to a higher speed can help it grab more of the stuff that gets kicked into the air. Ready to find the right high-CADR purifier for your space? Check out our range of quiet and affordable purifiers, with the highest CADR in New Zealand for their price brackets. View High-CADR Air Purifiers

If you've been searching for Air Purifiers recently on Google here in New Zealand, you may have come across ads identifying the "Top 5 Air Purifiers in NZ" or "Top 5 Air Purifiers for Allergies in NZ" looking something like this: Who's running this campaign? Quickly, we notice it's from brands we've never heard of here, Hotselects and Trustyrates? Well, that's because it's an ad campaign run by a company in China, funneling people to buy their unknown air purifier: Attempting to Sound Credible If you go onto the websites, at first glance it appears legit. Run by someone called 'Evan Mitchell' who is apparently a seasoned air purifier reviewer. However a quick google turns up no information on him, and the picture looks AI generated. It's also a little strange he runs both websites, and his email address is matt@trustrates.com for one of them! The descriptions are also very clearly AI generated:   Now onto the content. It does include useful pointers on what to look for (HEPA filters, high CADR and avoiding ionisers. Okay, all fine with us - we'd agree these are all useful things for people to know when choosing an air purifier. Now, who's the Surprise Winner? Funny enough, the number one rated purifier on each site is one we've never heard of before! They aim to make it sound more legit by including comparisons to other well-known products such as the Dyson TP09 or the Levoit 600S. You can clearly tell it's designed to promote one specific product, as the winner is also the only one with a link to view the product! Hotselects Winner: Marvics Air Purifier Well, a very clear winner here. So many pros, and the only cons being that it's online only and frequently sold out due to high demand! Although it's not lost on us that it shows a Pro as being negative ion generation, yet just above it says to avoid ionisers. Almost sounds too good to be true... Trustrates Winner: GLO Air Purifier Another one we've never heard of. It includes all the same features and pros as the Marvics purifier, the same cons! Even the same picture... Let's take a look at the product Conveniently the Marvics is on sale for only $309, saving $260! Lucky we got in now before the sale ends in less than 10 hours. Although, when I looked a few weeks ago there was the exact same sale - must have been a coincidence. 7743 sold in total and only 3 left, boy they're putting the pressure on for you to buy now! They've hit all the classic sales and trust cues. Raving reviews from Consumer Reports, CNET, Wired, Fox News. Heck, even the Cambridge Dictionary has reviewed them - must be really something special! Even more amazing, given it has a quoted Clean Air Delivery Rate (CADR) of 80m³/hour, which is one of the lowest of any purifier you can find. Of course, if you try google these reviews you'll turn up a blank. Because Marvics/Glo has no presence anywhere else. It only exists in this eco-system, built by AI to funnel people to a seriously overpriced air purifier. Looks like they're doing this around the world, as their Trust Pilot page shows quite a few very unhappy customers... Not Just Air Purifiers As a bonus, they have a dehumidifer too which no doubt follows the same path. Here's how the deeply inspiring story at the bottom of each product compares! Bottom Line Be careful when searching online, and seek out trusted local suppliers and sources of information. If you really want the Best Air Purifier in New Zealand, we've got you covered with our range!