Choosing an air purifier is really two questions in one: how much clean air does the room need, and what do you actually want it to do? Get those right and the choice almost makes itself. This guide maps the room you are treating — a bedroom, an open-plan living space, a smoky kitchen — and the need behind it — particles, odours, silence, or the fun of a DIY build — onto the four kits in our range. Every kit shares the same MERV-13 filtration and the same low running cost, so this is not about which is “best” in the abstract. It is about matching clean-air delivery to your square footage and picking the filter and finish that suit how you live. We will explain the sizing maths in plain terms, then set the options side by side so you can decide in a couple of minutes.
681 m³/h CADR, MERV-13, under 35 dB — powerful whole-home clean air — no proprietary lock-in, ships from the UK.
Check price →Use code KITS10 for 10% off at checkout.Start with the room, not the product
The single most useful number when buying an air purifier is its clean-air delivery — how many cubic metres of genuinely filtered air it produces every hour. A purifier that is too small for the room will keep running without ever quite getting on top of the air; one comfortably matched to the space clears it several times an hour and holds it there. So before you look at any product, look at the room.
Measure the floor area in square feet (or metres) and note what you mainly want to tackle. Fine particles — dust, pollen, smoke, airborne respiratory particles — are handled by any MERV-13 kit. Odours, cooking smells and volatile organic compounds (VOCs) are gases, not particles, and need activated carbon on top of the particle filter. Silence, portability and whether you enjoy a bit of DIY are the finishing touches that decide between otherwise similar kits. Hold those three things in mind — area, particles-versus-odours, and finish — and the rest of this guide is just matching them up.
How sizing actually works: clean-air delivery vs room size
Here is the principle without the jargon. A room needs its full volume of air cleaned several times an hour for a purifier to keep pace with the dust, pollen and particles constantly being stirred back into it. The bigger the room, the more clean air per hour you need. That is why we quote a clean-air figure in cubic metres per hour and a room-size range in square feet for each kit — the two go together.
Filter and finish options explained
Every kit in the range uses MERV-13 filtration, which captures roughly 93 per cent of airborne particles — PM2.5, pollen, dust and a large share of airborne respiratory particles. That is the common baseline. Where the kits differ is in two things: capacity (covered above) and whether they add activated carbon.
Compare the range at a glance
Still unsure? A quick decision path
Work through it in order and you will land on one kit:
Whichever you pick, the filtration principle is identical — pull room air through MERV-13 — so you are really choosing capacity, odour control and finish. When in doubt between two sizes, size up: a bigger kit run gently is quieter and longer-lived than a small one run flat out.