About AirFiltersDelivered (US)

An American retailer selling replacement air filters for home heating and cooling systems, shipped direct to the door. It carries its own house brand alongside recognised names, and the whole business rests on a chore people forget: a filter that ought to be changed every few months and usually is not.

Because filters are bulky and cheap individually, the site is built around multi-packs and repeat delivery rather than one-off purchases.

Getting the size right

Filters are described by nominal size — the number printed on the frame — which is rounded. The actual cut size is up to half an inch smaller in each direction. Order by the nominal number stamped on the old filter rather than by measuring it with a tape, or you will end up half an inch out.

If the old filter has gone, measure the slot and round up to the nearest common size. Depth counts as much as height and width: a four-inch filter will not go into a one-inch slot.

What MERV actually means

MERV rates how much a filter captures. Low ratings catch dust and lint, middle ratings catch pollen, mould spores and pet dander, high ratings catch fine smoke particles.

Higher is not automatically better. A dense filter restricts airflow, and a residential blower that was not designed for it works harder, runs hotter and costs more to operate. A mid-range MERV is the right answer for most home systems unless an installer has said otherwise.

How often to change it

Every quarter is the common guideline, shortening to monthly with pets, smokers, allergies in the house or construction dust nearby. Write the date on the cardboard edge as you fit it — that one habit removes all the guesswork.

Fit it with the airflow arrow pointing towards the blower. A filter installed backwards restricts airflow and collapses over time.

Using an AirFiltersDelivered discount code

Build the multi-pack or set up the recurring order first, then apply the code at checkout. Subscription pricing and a one-time code do not always stack, so compare both totals before committing to either.