Back to school - clean air for every classroom

Because they deliver high performance, low noise, excellent value, and include the educational support we are recognised for. The Blast was part of an earlier audit commissioned by the GLA where it was found that the Blast reduced PM_2.5 levels by up to 68% compared to classrooms without filtration.

Yes. Research shows that improving indoor air quality reduces the spread of airborne illnesses. For schools, this means fewer staff sick days and fewer supply teacher costs, which are often one of the biggest budget pressures. Even a small reduction in absences can save significantly more than the running cost of the units.

• Bradford Class‑ACT: Classrooms using HEPA filtration saw 20% fewer absences.
• Dover College study: The Blast Mini in a classroom recorded 47% fewer illness-related absences than unfiltered classrooms.
• GLA pilot study: The Blast unit reduced harmful PM2.5 by 68.4% compared to unfiltered classrooms.
• SAMHE project: Cleaner air was associated with up to a 15% improvement in pupils’ concentration.

While we always say that some clean air is better than none, we recommend the Blast and the Blast Mini as the most effective way to filter air in typical UK classroom sizes - Based on our experience delivering the Mayor of London's School Filters Programme, around 75% of classrooms received the Blast air cleaner based on classroom dimensions.

Our goal is to help schools achieve an equivalent of 6 air changes an hour (ACH) as recommended by the NEU (National Education Union) at low noise levels of under 45dBA. Most classrooms typically have around 1.5 ACH through natural ventilation, so your air cleaner only needs to achieve 4.5 ACH to make up the balance - assumes closed windows. Note that mechanical ventilation will deliver fresh air to the room, but most in-built filters are too course to remove particle pollution from the room (see next FAQ).

Schools that opt for small domestic units or models with automode (which often default to lower speeds) tend to see less impact from their investment. The Blast is our preferred choice for classrooms as it is one of the few air cleaners that cleans the air quickly enough for 30 active pupils.

The Blast is built big for a reason. It delivers the right level of clean air quietly, efficiently, and without ionisers (after all, why introduce even small amounts of ozone into a room full of children?).

So yes, you can choose smaller, but you may be compromising on protection - or find you’re not seeing enough impact to justify the cost.

Most built-in school ventilation systems don’t actually filter the air in a way that reduces illness or allergy-related absences (respiratory aerosols). The filters used are typically coarse (G4/F5 level), designed to protect the ventilation equipment, not to capture the fine particles that trigger asthma, carry viruses, or worsen allergy symptoms.

These systems move air, but they don’t 'clean' it. They dilute classroom air by mixing it with outside air, but they don’t remove the particles that cause health issues. In fact, in polluted parts of the country, this can mean bringing additional pollution indoors. It’s worth checking with your ventilation provider to confirm what grade of filter your system uses and whether it can be upgraded to a higher-efficiency option to offer better protection.

To reduce the things that genuinely affect attendance (viruses, fine pollution PM₂.₅, and airborne allergens), a classroom needs a high-efficiency air cleaner with enough power to clean the full room volume repeatedly throughout the day. That’s something standard built-in ventilation simply isn’t designed to do.

Portable high-capacity air cleaners work alongside your existing ventilation, adding the level of filtration needed to meaningfully reduce exposure for pupils and staff.

Running costs are low, typically less than a classroom computer. Timer switches ensure units only run during school hours, keeping energy use predictable and manageable.

As an example, running 20 Blast units costs just £8.60 per week* to provide cleaner air for up to 600 pupils and 20 teachers in a triple-form entry school with 20 classrooms.

Research from the Bradford ‘Class ACT’ trial showed classrooms with HEPA filters had 20% fewer illness-related absences. Based on the average cost of supply teachers in the UK, this could save your school around £218 per week!

If you want to work out your own energy usage based on the number of classrooms you have, please download our energy calculator (download excel)

*Assumption on May 2025 prices of 11.5-12.6p per kw hour, timer switches are set to 08:30-16:30 Mon-Fri and switched off during school holidays and the air filters are run on high or medium speed. This weekly cost covers filters in a triple-form school.

No - all units are plug‑and‑play. Timer switches are included.

You can purchase via our website or through national educational provider YPO but note they may not offer the same bulk prices as we do. There are 3 ways you can purchase direct from us:

• For smaller numbers, you can purchase direct from our website but to benefit from reduced prices for 9+ units, email [email protected] for a proforma invoice
• You can pay using a credit card or via BACs, delivery is usually within 3-5 days of payment
• We offer a leasing option through Kennet Leasing where you can spread the cost over 2, 3 or 5 years

Only to benefit from the school discounted pricing. There is a minimum of 9 units but this can be one type of unit or a mix of any of our 3 air cleaners. All other quantities can be purchased direct from our site at the standard retail price.

Our leasing provider, Kennet Leasing, has a minimum spend of £1,000 for leasing arrangements.

If you have any question on pricing, please email [email protected].

The Blast and Blast Mini come with placement brackets which takes the guesswork out of the minimum distance from the wall for full, uninterrupted airflow. These brackets can also be used to secure the units to the wall which we recommend for the full-size Blast filters - optional for the Blast Mini.

Please note these are not wall-mountable, they are floor standing units with brackets to secure to the wall if extra stability is needed.

We don't just sell you an air cleaner and move on to the next school. We have put a lot of thought about how we can achieve the equivalent of 6 air changes an hour a noise levels conducive to teaching. We know that schools are worried about energy consumption and giving teachers yet another thing to think about. We are constantly improving our services but we see ourselves being part of your clean air journey for many years.

Blast

User manual

CADR: 450 - 950 m³/h
Noise: 29 - 43 dB
Filters: H13 HEPA (optional carbon)

Best for: Sports/assembly halls, large open-plan classrooms, high-traffic student areas, and contingency learning spaces.

Pre-programmed timer switch

We'll programme your timer switch to automatically turn the air filter on or off at pre-set times (default Mon to Fri from 8.30am to 4.30pm). This helps manage energy use without relying on teachers.

Blast Mini

User manual

CADR: 340 - 740 m³/h
Noise: 36 - 49 dB
Filters: H13 HEPA (optional carbon)

Best for: Early years classrooms, shared study areas, specialist classrooms, and science laboratories.

Placement brackets and wheels

Designed for school environments, the brackets ensure the correct clearance for unimpeded airflow but can also be used to secure to the wall. The lockable wheels should be engaged once plugged in.

Outdoor air quality monitor

Spec sheet

Sensors: PM2.5, CO2, TVOC, NOx
Connection: 4m USB cable
Wi-Fi: 2.4GHz

Best for: Hyperlocal monitoring right outside the school gates, monitor the air during school pick-up and drop-off.

Extend filter cartridge lifespan

We’ll remind you each term to switch the filters back on. Turning them off during holidays helps the HEPA last longer, while cleaning the pre-filter keeps them quiet and efficient.

The Blast and Blast Mini come with HEPA filter as standard with carbon filters as optional. The SA600 comes with both HEPA and Carbon filters as standard. All units come with pre-filters which require maintenance.

Pre-filter maintenance

This should be included as part of your regular cleaning routine, ideally managed by your cleaning contractor to reduce the workload on school staff. The cleaning instructions above can be shared directly with them. Keeping the pre-filter clear is important because a clogged filter can make the fan work harder, increasing noise and reducing filtration efficiency.

Pre-filters trap coarse particles and should be cleaned monthly.

⚠️ Avoid standard vacuuming unless using a sealed, bagged HEPA vacuum. Unsealed vacuums may resuspend trapped particles and worsen indoor air quality.

HEPA filter lifespan

Based on average UK pollution levels and consistent daytime use with timer plugs (set to 8:30 am–4:30 pm, Monday-Friday), we can estimate when your HEPA filter cartridge will need replacing:

Running your air filter Monday to Friday all year round (52 weeks) can shorten its lifespan by up to 1.5 years compared to switching off during school holidays. If your caretaker powers down sockets at the end of term, our first-day-back email reminders make it effortless to restart and keep clean air flowing from the first day of every term.

These filter cartridge lifespan estimates assume typical UK indoor air conditions. In schools with high outdoor pollution, building work, or elevated occupancy, filter cartridges may require earlier replacement.

Carbon filter cartridge

How frequently a carbon cartridge needs replacing depends on too many variables so we recommend changing this annually. Our units are designed to work with or without carbon filters so if you don't wish to replace the carbon filters in the SA600, it will actually give you an increased CADR as there is less resistance.

While air filters are most effective at reducing levels of particulate matter in classrooms when windows are closed, opening windows and ventilating the classroom is vital for removing other pollutants including VOCs (including from cleaning chemicals) and CO2 which can affect cognitive performance. Opening windows for even a short period of time can have significant benefits for indoor air quality.