What's the cheapest way to get clean air?

Building your own Corsi-Rosenthal box for around £60. A ready kit costs more but is quieter and tidier.

How do I keep costs down long-term?

Use standard MERV-13 filters (~£40/yr), not proprietary cartridges — the biggest ongoing saving.

Corsi-Rosenthal Box Kit Deals UK: Current Discount Code

Use code CORSI10 for 10% off CleanAirKits

Applies automatically at checkout across the Luggable range — MERV-13 filtration, up to 681 m³/h CADR, standard replacement filters, ships assembled. Building your own is still the cheapest option of all (see below) — but if you’d rather buy it done, this is the current offer.

Check price on the Luggable →

There is more than one way to save on clean air. The cheapest clean air of all is a Corsi-Rosenthal box you build yourself for around £60 — nothing beats it on value. Here's how to get the best value whether you build or buy.

Our recommendation

CleanAirKits Luggable XL Ultra (7-Fan)

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 CORSI10 for 10% off at checkout.

Cheapest of all: build your own (~£60)

A box fan, four or five MERV-13 filters and some tape deliver clean-air rates rivalling purifiers costing far more. Follow the build instructions and source parts via UK suppliers.

The saving that matters most: standard filters

Whether you build or buy, insist on standard MERV-13 filters (around £40 a year) rather than proprietary cartridges (£80–150 a year). Over three years that choice saves more than any one-off offer.

Run it efficiently

Efficient fans cost about £2 a year to run continuously; a box fan a little more. Run lower speeds when the air is already clean. See energy costs and cheapest indoor air purification.

CR box kit deals