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4″ furnace filters

4-inch furnace filters, MERV 8 efficiency, sold in boxes of 6. 9 sizes in stock, made in Canada.

Made in Canada Free shipping Shipped within 24 h Replace every 3 to 5 months
−13 %
20 × 20 × 4

Filter 20x20x4 – MERV 8

Actual 19 1/2″ × 19 1/2″ × 3 3/4″
  • Box of 6 filters · made in Canada
  • At least 70% of 3 to 10 µm particles
  • Replace every 3 to 5 months
$125.00$144.00Plus taxes · $20.83 per filter
● In stock · ships within 24 hAdd to cart
16 × 20 × 4

Filter 16x20x4 – MERV 8

Actual 15 1/2″ × 19 1/2″ × 3 3/4″
  • Box of 6 filters · made in Canada
  • At least 70% of 3 to 10 µm particles
  • Replace every 3 to 5 months
$125.00Plus taxes · $20.83 per filter
● In stock · ships within 24 hAdd to cart
−30 %
24 × 24 × 4

Filter 24x24x4 – MERV 8

Actual 23 1/2″ × 23 1/2″ × 3 3/4″
  • Box of 6 filters · made in Canada
  • At least 70% of 3 to 10 µm particles
  • Replace every 3 to 5 months
$140.00$200.00Plus taxes · $23.33 per filter
● In stock · ships within 24 hAdd to cart
−30 %
20 × 25 × 4

Filter 20x25x4 – MERV 8

Actual 19 1/2″ × 24 1/2″ × 3 3/4″
  • Box of 6 filters · made in Canada
  • At least 70% of 3 to 10 µm particles
  • Replace every 3 to 5 months
$140.00$200.00Plus taxes · $23.33 per filter
● In stock · ships within 24 hAdd to cart
−13 %
16 × 25 × 4

Filter 16x25x4 – MERV 8

Actual 15 1/2″ × 24 1/2″ × 3 3/4″
  • Box of 6 filters · made in Canada
  • At least 70% of 3 to 10 µm particles
  • Replace every 3 to 5 months
$125.00$144.00Plus taxes · $20.83 per filter
● In stock · ships within 24 hAdd to cart
−3 %
20 × 24 × 4

Filter 20x24x4 – MERV 8

Actual 19 1/2″ × 23 1/2″ × 3 3/4″
  • Box of 6 filters · made in Canada
  • At least 70% of 3 to 10 µm particles
  • Replace every 3 to 5 months
$140.00$144.00Plus taxes · $23.33 per filter
● In stock · ships within 24 hAdd to cart
−13 %
18 × 24 × 4

Filter 18x24x4 – MERV 8

Actual 17 1/2″ × 23 1/2″ × 3 3/4″
  • Box of 6 filters · made in Canada
  • At least 70% of 3 to 10 µm particles
  • Replace every 3 to 5 months
$130.00$150.00Plus taxes · $21.67 per filter
● In stock · ships within 24 hAdd to cart
−30 %
16 × 24 × 4

Filter 16x24x4 – MERV 8

Actual 15 1/2″ × 23 1/2″ × 3 3/4″
  • Box of 6 filters · made in Canada
  • At least 70% of 3 to 10 µm particles
  • Replace every 3 to 5 months
$140.00$200.00Plus taxes · $23.33 per filter
● In stock · ships within 24 hAdd to cart
−13 %
12 × 24 × 4

Filter 12x24x4 – MERV 8

Actual 11 1/2″ × 23 1/2″ × 3 3/4″
  • Box of 6 filters · made in Canada
  • At least 70% of 3 to 10 µm particles
  • Replace every 3 to 5 months
$125.00$144.00Plus taxes · $20.83 per filter
● In stock · ships within 24 hAdd to cart
Compare

Same size, other depths

20 × 20 × 120 × 20 × 2See all 46 sizes →
The guide

When to replace a 4-inch filter?

Replaceevery 3 to 5 months
A box of 6lasts 1½ to 2½ years
Rule of thumbGrey? Replace it.

4" Filters

Made in Canada

Filters made here.

Our pleated MERV 8 filters are made in Canada, then shipped within 24 hours. Made here means consistent quality from one box to the next, short lead times and local jobs.

  • Made in CanadaOur MERV 8 filters are made here, not overseas.
  • Consistent qualityThe same size, the same pleats, from one box to the next.
  • Short lead timesIn stock, they ship within 24 hours.
  • A local companyOur team is in Saint-Eustache, Quebec.
Questions

Frequently asked questions

Where do I find my filter size?

It is printed on the side of your current filter’s frame: width × height × depth, in inches. That is the “nominal” size, the one you order.

Which way does it go in?

The arrow printed on the frame points toward the furnace, in the direction of the airflow.

How often should I replace it?

A 1″ filter is replaced every month, a 2″ every 1 to 2 months, a 4″ or 5″ every 3 to 5 months. Check it every month: as soon as it is grey, replace it.

Where are your filters made?

Our MERV 8 filters are made in Canada.

My size is not in the list.

Check the size printed on your filter: the actual measurements are a little smaller than the nominal size. If in doubt, call us at 1-844-995-8677: we will help you find the right one.

A question about your size?

Your filter, made in Canada, shipped within 24 hours.

Made in CanadaShipped within 24 hFree shippingA team that listens
Call 1-844-995-8677Find my filter Monday to Thursday, 8 a.m. to 5 p.m. · Friday, 8 a.m. to 3 p.m.
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