Fresh air: A look at air purifiers

The warm weather is here. Time to throw open the doors and windows to air out the house, right? Unfortunately, the changing seasons can bring itchy eyes and constant sneezing for many of us. The dreaded hay fever can often be the gateway into air purification for many Australians, as sufferers seek ways to alleviate the annoying symptoms. Putting an air purifier in the home can indeed help ease the sneeze.

But it’s not just allergy sufferers that benefit from air purification in the house. We do tend to spend a lot of time indoors, and dust mites (the enemy of asthmatics), pet dander, smoke, chemicals, and mould spores are some of the other household irritants that can cause potential health hazards that air purifiers may help to eliminate.

How do they work?

Portable air purifiers are commonly found in the home and used to filter the air in a single room. In simple terms, once in operation, an air purifier uses a fan to draw the air from the room through either one or a series of filters. It’s these filters that trap the pollutants. The clean air is then cycled back into the room, and the process is repeated. Air purifiers can only trap airborne particles.

Caught in the act

Right, so now you know how they work, just what can the magic filters catch? This is dependent on several factors. The most important of these is the quality of the air purifier and what filters are in operation. Like any consumer tech, air purifiers come in a range of designs for various budgets. Therefore, expecting an entry-level model to perform as effectively as a larger, feature-rich air purifier at the higher end of the price scale is unrealistic.

Capture kings

The filter is an essential part of the air purifier – without one, it's useless. The filter's job is to catch all of the nasties from the list on the right and prevent them from circulating in the air that we breathe. Like a vacuum cleaner or an oil filter in the car, unless regularly replaced, the filter’s effectiveness will reduce over time. As such, it’s important to follow the manufacturer’s advice on the frequency they need to be changed. Most air purifiers will prompt the user when it’s time for a new filter.

Some filters can be washed and reused, helping the environment and the back pocket. Bottom line: change or clean the filter as required to ensure that the unit and its performance continue to operate at an optimum level.

Bells and whistles

Depending on the price tag, air purifiers come with a range of different features. Alongside the basics, some models can double as a heater in the winter or a fan in the summer. Some offer variable speeds for flexibility in filtering the air, and others have an oscillating head to cover more of the room area. If you’re a light sleeper, look for an air purifier with a quiet mode for overnight operation. As we’ve already mentioned, several air purifiers come with an inbuilt warning to replace the filter – a handy addition for a busy household. Establishing what features best suit your household is a great place to start before shopping.

I keep seeing the letters CADR on air purifiers. What’s the deal?

The Clean Air Delivery Rate, or CADR, is an industry-standard measure of how efficient an air purifier is based on the size of a room and the amount of clean air produced by the minute. The results are converted to cubic metres per hour when units are initially tested. The three pollutants used in the testing process are dust, smoke, and pollen. So essentially, the higher the CADR rating, the better the air purifier will perform.

Smart cleaning

Smart technology extends to air purification, with some units offering Wi-Fi connectivity. This brings voice control into play and remote operation. Depending on the brand, information about the type of pollutant collected can be relayed to an app, and speeds can be adjusted depending on the job required.

Filter focus

Different filters perform different tasks. The most popular type in domestic air purifiers is the HEPA filter, although some units will combine multiple filter systems in one unit.

HEPA: The most common type of filter, HEPA, is an acronym for High-Efficiency Particulate Air. The filter is a multi-layered fine mesh netting designed to catch various-sized particles. A True HEPA filter can capture over 99.97 per cent of pollutants.

Carbon: A carbon filter is an efficient filtration system due to its porous nature. The absorbent material makes it ideal for gases and odours that HEPA filters can’t catch.

Ozone: An ozone filter is excellent for neutralising odours but will not trap any other impurities in the air.

UV: UVC sanitation has become more and more popular over the last two years for obvious reasons. In air purifiers, you’re most likely to find UVC technology working in conjunction with a HEPA filter. For example, as the air flows through the filter, the UV light shines, potentially killing mould spores, bacteria, and viruses as clean air exits into the room.

Monster Hunter

Well, the word "monster" is a little extreme, but there's a slew of airborne nasties that an air purifier can catch if the right filter is used. Here are some that you'll want to banish.

Pollen

Many of us know this one. It might be seasonal, but it can cause significant discomfort to hay fever sufferers. Throwing open a window to air out the house or a poorly sealed room can be enough to trigger the dreaded symptoms.

Pet dander

For asthmatics or allergy sufferers, pet dander is right up there as a major irritant. The cause is a protein found in tiny particles of skin shed by pets. Pet saliva can also contain this protein, which can be released when an animal scratches.

Dust mites

Like pet dander, dust mites are the enemy of asthmatics. Dust mites love eating discarded human skin particles (*gag*) and seek refuge in beds, carpets, clothes, and couches. Dust mite poop causes the issue, so every time a soft furnishing in the home is disturbed, this ‘dust’ is sent airborne!

Smoke

You don’t want bushfire smoke, tobacco, or even burnt toast in the house for obvious reasons.

Mould spores

Yep, mould in the house is a big no-no and can have respiratory health implications.

Bacteria and viruses

Bacteria and viruses can often be airborne in the house.

Volatile Organic Compounds (VOC)

VOCs are gases emitted from paint, paint strippers, thinners, glues, and cleaning products.

OK, I’m in. What’s the next step?

Right, you’ll need a tape measure for this bit. Measuring the size of the room where the air purifier will sit will help you choose the suitable model for the job. An underpowered unit will under perform in a big space, and conversely, an overpowered unit will just chew the juice and add unwanted numbers to your electricity bill.

The good news is that most models will openly display coverage rates in metreage. To work out the metreage, the formula needed is length multiplied by width. This will give the total area. So, if a room is five metres long and four metres wide, the total area is 20m2. Adjoining rooms that an air purifier will service will need to be calculated and added to the total surface area.

As a rule of thumb, it’s better to buy an air purifier that will cope with a slightly larger area than the one required.

5 top tips to help you shop for the right air purifier

1. Opt for a model that runs quietly and is energy efficient.

2. If you’re running an air purifier regularly, it might be worth looking at filters that can be cleaned or washed.

3. If you intend to continually move the air purifier around the house, consider the unit's weight.

4. If your device has a HEPA filter, ensure it’s a True HEPA filter. To achieve this status, the filter must have a 99.7 per cent efficiency rate with particles up to 0.3 microns.

5. Invariably, in the world of air purification, you do pay for what you get. Don’t undersell a room size to save on a few bucks.

Clean dream

Here are six air purifiers to suit all budgets.

Breville Smart Air Viral Protect Plus Purifier

Designed to cater to a medium-sized room (up to 42m2), this smart air purifier is voice control enabled and uses sensors to alter the performance based on the air quality. Four-stage air filtration targets dust, pet dander, smoke, odours, and, importantly, bacteria and viruses, reducing SARS-CoV-2 by 99.7 per cent.

Philips 1000i Series Air Purifier

Covering up to 78m2, the Philips 1000i has a CADR of 300 m3/h. Energy efficient, it has a quiet mode for nighttime use and a 3-1 integrated filter alleviating the need to swap out separate filters. A sensor will set the right speed for the different environments required. The filter will trap pet dander, gases, pollen, dust, smoke, and bacteria.

Dyson Purifier Cool Purifying Tower Fan

This tower of power covers 81m3, can be voice controlled, and will detect and report on airborne particles and gases trapped. Its filter system can remove gases and 99.95 per cent of particle pollution. The purifier oscillates 350 degrees and doubles as a fan in the summer. An automatic filter reminder will let users know when it’s time to change, and it even comes with a remote control.

Breville Smart Dry 2-in-1 Viral Protect Dehumidifier

An excellent option to cover all bases, this model from Breville combines an air purifier with a dehumidifier. Effective in areas up to 60m2, it’s voice control compatible and features Bluetooth and Wi-Fi connectivity. A three-stage filtration system catches the usual suspects and is effective in trapping SARS-CoV-2 (99.97 per cent) and Influenza A (99.99 per cent) viral particles. It can extract up to 25 litres of water daily as a dehumidifier.

Soho SO-350WUI Air Purifier

If a large surface area needs to be covered, this one is a good option. It can purify the air up to 90m2, so it would be suitable for big rooms, classrooms, and offices. It’s voice-controlled for easy operation and is fitted with a five-stage purification, including an ioniser and UV to catch all the nasties.

TruSens Z-1000 Air Purifier

A good option for smaller spaces, the sleek Z-1000 will work in areas up to 23m2 but still comes feature-laden. It captures pollen, VOC gases, and germs, and bacteria with UV light. It also has a proprietary technology that splits the airflow for better room coverage, and a filter replacement indicator.