Use Case: Medical

The short answer

At its maximum setting, one HA500 adds about 10–17 equivalent air changes per hour (eACH) of clean air to a typical 12–20 m² consulting room or dental surgery. A 40 m² waiting room needs one HA800 or ceiling-mounted HA-C800 to add 6 eACH or more. Air cleaning supplements ventilation; it does not replace it, and it does not by itself prevent infection. Final selection depends on the room’s ventilation, the setting you will run the unit at, and noise.

What UK guidance says

NHS England’s HEPA filter device bulletin (NETB 2023/01A, an addendum to HTM 03-01) supports portable HEPA devices where ventilation is poor or below HTM 03-01 standards, as a supplement, never a reason to reduce ventilation.
It asks for H13 or H14 HEPA filtration, test data for the complete device, noise of no more than 50 dB at 3 m in normal use, and maintenance by a competent person.
It does not currently recommend ionisation, PCO or electrostatic technologies unless safety and effectiveness are clearly evidenced. The negative-ion function on HATL units can be switched off, and we recommend running with it off in clinical rooms. The HA800 turns it on at power-up, so switch it off each time the unit is started.
HATL holds test certificates for complete units and for filter components. Ask us for the documents for the model you are considering.

How many units?

Ceiling height 2.5 m. Clean air added by each unit at maximum setting.

Room	Floor area	Volume	One HA500 adds	One HA800 / HA-C800 adds	Units to add 4 eACH	Units to add 6 eACH
Consulting room	12 m²	30 m³	16.7 eACH	26.7 eACH	1 × HA500	1 × HA500
Dental surgery	16 m²	40 m³	12.5 eACH	20.0 eACH	1 × HA500	1 × HA500
Treatment room	20 m²	50 m³	10.0 eACH	16.0 eACH	1 × HA500	1 × HA500
Waiting room	40 m²	100 m³	5.0 eACH	8.0 eACH	1 × HA500	1 × HA800 or HA-C800
Large waiting area	60 m²	150 m³	3.3 eACH	5.3 eACH	1 × HA800 or HA-C800	2 × HA800 or HA-C800

The table shows the clean air the purifier adds at its maximum setting. Existing ventilation also counts towards the total. At quieter settings each unit delivers less clean air than shown. Final selection depends on occupancy, ventilation, room layout, noise and the requirements of the setting. In clinical rooms, check the intended operating setting, the room’s ventilation rate, noise and whole-device evidence before deciding.

Running cost

At maximum setting for 10 hours a day, 5 days a week (2,600 hours a year), at 26.32p/kWh excluding VAT, electricity costs approximately £31 a year for an HA500, £55 for an HA800 and £48 for an HA-C800. Running at a lower setting costs less, but also delivers less clean air. Business tariffs differ.

Filters: an HA500 replacement set (two filters) costs £150 and an HA800 set £240, including VAT. In typical UK use a set lasts about two years — roughly £75 or £120 a year. Replace filters according to HATL’s instructions, the unit’s filter warning and your practice’s maintenance procedures. For HA-C800 filter prices, ask HATL.

What HATL’s evidence shows — and doesn’t

Real clinic: in a 10-working-day study at Sunrise Medical Practice, Nottingham, carried out by Nottingham Trent University’s Medical Technologies Innovation Facility (MTIF) and funded by a Medilink Midlands Innovation Support Grant, airborne mould counts in the practice room fell to zero in every sample taken while the purifier was running, and mould in the busier corridor and waiting area was about 76% lower. Practice-room bacteria counts were about 75% lower on a median basis (about 53% lower on average) than in the three days before the purifier was installed, and rose again by around 60% once it was removed. Corridor bacteria counts varied more and fell less. These are HATL’s calculations from all 46 samples in MTIF’s report, with none excluded. The study ran for 10 working days at one practice, had no separate comparison room, and did not measure viruses or infection rates.
Laboratory: in a 30 m³ test chamber, the HA800 reduced the H1N1 virus indicator by at least 99.9% within 60 minutes (SGS), and the bacteria E. coli and S. albus by more than 99.99% within 60 minutes (see Evidence & Test Results). Some HATL tests, including the CADR tests, were run with the negative-ion function on. These are chamber results for the tested model and conditions, not infection-prevention results, and do not transfer to other models.

FAQs

Can an air purifier replace ventilation in a consulting room?

No. NHS England guidance says HEPA devices supplement ventilation and should never be a reason to reduce it.

How many air purifiers does a dental surgery need?

For a typical 16 m² surgery with a 2.5 m ceiling, one HA500 adds about 12.5 eACH at maximum setting. Whether one unit is enough at the setting you will actually use, alongside your ventilation, needs a site check.

Will an air purifier stop infections spreading in my practice?

No device can promise that. In HATL’s clinic study, practice-room mould counts fell to zero while the purifier ran and bacteria counts were about 75% lower on a median basis, but the study did not measure infection rates. Air cleaning is one layer alongside ventilation, cleaning, PPE and triage.