How often should I change the filter?

A 1" pleated filter every one to three months; a 4" or 5" media filter every six to twelve. Shorten that if you have pets, are renovating, or are in wildfire smoke season — which in BC now regularly means late summer.

Is a higher MERV rating always better?

No. A higher MERV catches finer particles but restricts airflow more, and a filter too restrictive for your blower causes exactly the overheating and short-cycling you were trying to avoid. MERV 8 to 11 suits most residential furnaces. Check what your furnace is rated for before going higher.

Which way does the arrow point?

The arrow points in the direction of airflow — toward the blower and away from the return duct. A filter fitted backwards restricts airflow and collapses into the blower.

Furnace Air Filters & Cleaners

We sell directly to the homeowner

The filter protects the blower and heat exchanger, and a blocked filter is the most common cause of furnace faults we see — restricted airflow trips the high limit, overheats the heat exchanger, and short-cycles the furnace. It is the cheapest part in the system and the one most likely to be behind an expensive-looking symptom.

9 air filters & cleaners in stock, ready for same-day pickup at our Coquitlam warehouse or shipped worldwide.

Signs your air filter may have failed

Furnace short-cycles or trips the high limit switch
Weak airflow at the registers
Visible dust on the filter face, or daylight no longer visible through it
Higher heating bills with no change in the weather

Not sure which part you need? Call 1-778-759-9864 with your furnace model number and we will confirm it before you order.

Shop air filters & cleaners by brand

Lennox9

Air Filters & Cleaners we stock

Air Filters questions

How often should I change the filter?: A 1" pleated filter every one to three months; a 4" or 5" media filter every six to twelve. Shorten that if you have pets, are renovating, or are in wildfire smoke season — which in BC now regularly means late summer.
Is a higher MERV rating always better?: No. A higher MERV catches finer particles but restricts airflow more, and a filter too restrictive for your blower causes exactly the overheating and short-cycling you were trying to avoid. MERV 8 to 11 suits most residential furnaces. Check what your furnace is rated for before going higher.
Which way does the arrow point?: The arrow points in the direction of airflow — toward the blower and away from the return duct. A filter fitted backwards restricts airflow and collapses into the blower.

Need it today in Greater Vancouver?

Call ahead and we will set the part aside at the Coquitlam counter. No account, no trade card, no minimum order.

1-778-759-9864 Pickup details

Signs your air filter may have failed

Shop air filters & cleaners by brand

Air Filters & Cleaners we stock

30" X 58" X 1" LENNOX HAMMOCK FILTER

25" x 16" x 5" Healthy Climate HCF16-11 Filter, MERV 11

20" X 25" X 5" HEALTHY CLIMATE HCF20-11 MERV 11

12.5" X 16" X 1" HONEYWELL POST FILTER X2

H/C PUREAIR PHOTOCATALYTIC CARTRIDGE

LENNOX A/C DUCTLESS SPLIT FILTERS PACKS OF 2

LENNOX A/C DUCTLESS SPLIT FILTER

LIFEBREATH MERV 13 FILTER (PACK OF 4)

LIFEBREATH HRV/ERV WASHABLE FILTER 8.125" X 13" X 0.75"

Air Filters questions

Need it today in Greater Vancouver?