Air purifiers have a reputation for being expensive to run — but that’s mostly true of high-wattage HEPA towers, not high-airflow MERV-13 kits. Here’s what a UK home actually pays, and how to keep it near-nothing.
681 m³/h CADR, MERV-13, under 35 dB, ~15 W (about £2/yr) — standard filters, no proprietary lock-in, ships from the UK.
Check price →Use code KITS10 for 10% off at checkout.The two costs: electricity and filters
Running cost is just two numbers: the electricity the fans draw, and the replacement filters over a year. Get both low and you can run clean air 24/7 without thinking about it.
Electricity: do the maths
Cost per year = watts × hours × days × tariff. At the 2026 UK price cap (~£0.25/kWh), left on all day:
| Unit type | Power | Running 24/7 |
|---|---|---|
| MERV-13 kit (Luggable) | ~15 W | ~£2–3/yr |
| Mid HEPA tower | ~45 W | ~£8–10/yr |
| Large HEPA (high speed) | ~90 W | ~£18–20/yr |
The gap is physics: high-static-pressure PC fans move a lot of air per watt, hitting the same clean-air delivery at a fraction of the power.
Filters: the hidden cost
This is where big brands get you. Proprietary HEPA cartridges run £30–£60 and are often due every 6–12 months. A MERV-13 kit uses standard 3M Filtrete filters you can buy anywhere for a fraction of that — no lock-in, no subscription.
Why “cheap to run” matters
A purifier only cleans the air while it’s on. Costly or noisy units get switched off — and then do nothing. A kit that costs ~£2/yr and runs under 35 dB is the one you leave on permanently, which is exactly what removes pollen, smoke and viruses around the clock.