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UK DIY Air Filters – (CR box)

Materials available to build a DIY air filter (also known as a CorsiRosenthal box, or CRbox) can vary by location. We feature two designs here.

UK Round Vent Axia 14″ box fan

Vent Axia 14 inch fan, 4 x 3M Filtrete MPR1900 – 20 x 25 x 1 inches

This build from @PeteUK7 details the method and materials available in the UK, using a round fan, and cardboard supporting it. (source tweet)

Instructions available at

UK Slimline Cooltone 12″ box fan

Cooltone 12″ box fan from London,

Filtrete 1900 or 2200 panels (14″ x 24″ x 1″), (14″ x 25″ x 1″) or (14″ x 30″ x 1″)

(source tweet)