E3M Filter Wholesale
Val-Des-Monts, Quebec CA
Phone: 8193073363 Website: www.homeairfilters.ca

Furnace Air Filter replacement frequency


The frequency of replacements depends of a few factors, where you live, unit operation and airborn dust in your home (pets, etc). For optimal performance change your filter every 3 month. Fact is that your filter is more efficient as the dust is lodged in filter however it should be changed when resistance is too high (approx 1" inch wc). Thicker filters have more filtering area and therefore can be changed every 6 month or less depending of usage. In fact thicker air filters have less resistance (approx 1/2 of 1" filters) and will use less fan energy hence saving valuable $$$.

Dirty Filter                      Clean Filter


Air Filter size and how to determine.


Some air filters have the size printed on the frame however you may not find it on other models. Air Filters sizes at E3M Filters are based on nominal size and not actual size. The actual size is slighter smaller than the nominal size in order to allow for easy installation and replacement. To determine size measure actual outside dimensions and round up to the nearest highest size. If you're not sure please contact us and we will step you through the process.

Some air filter size are not standard stock products in box stores and special order would be very expensive if even possible. That is not the case with E3M filters, we have all your  air filter sizes. Can't find it please contact us. 

Merv rating

Minimum Efficiency Reporting Value


Minimum efficiency reporting value, commonly known as MERV rating, is a measurement scale designed in 1987 by the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) to rate the effectiveness of air filters.

The scale "represents a quantum leap in the precision and accuracy of air-cleaner ratings and allows for improved health, reduced cost and energy efficiency in heating, ventilation and air conditioning (HVAC) design. For example, a HEPA filter is often impractical in central HVAC systems due to the large pressure drop the dense filter material causes. Experiments indicate that less obstructive, medium-efficiency filters of MERV 7 to 13 are almost as effective as true HEPA filters at removing allergens, with much lower associated system and operating costs.[2]

The scale is designed to represent the worst-case performance of a filter when dealing with particles in the range of 0.3 to 10 micrometers. The MERV rating is from 1 to 16. Higher MERV ratings correspond to a greater percentage of particles captured on each pass, with a MERV 16 filter capturing more than 95% of particles over the full range.

Below is a table grouping MERV ratings by particle size:



While the smallest MERV value in each row has no minimum requirement for filtering that row's particle size, it does have stricter requirements for all larger particle sizes than any smaller MERV value. For example, MERV 13 the "0.3–1.0 μm" row has no minimum requirement for removing 0.3–1.0 μm particles (the standard specifies "<75%") but has higher minimum removal percentages of 1.0–3.0 μm, 3.0–10.0 μm, and > 10 μm particles than MERV 12 and all smaller MERV values. All other MERV values on each row do have minimum removal percentages for that row's particle size

MERV rating is the only recognized method of determining filter efficiency , other methods like MPR are proprietary to manufacturers.


Looking for more information on energy savings tips for your home, consult the following links

Natural Resources Canada

Energy Star

Enbridge Gas

Ontario Ministry of Energy


Our Partners

Filtration Lab