Asked by: Diosinda Lastaola
home and garden indoor environmental quality

Can you cut air filters to size?

Last Updated: 23rd May, 2020

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Should you cut HVAC air filters to fit the space? The answer - NO! The purpose of the HVAC air filter is to keep the system clean. Yes, the TV commercials say that if you use this or that filter the air in the house will be cleaner and your children will be healthier.

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In this regard, what if my air filter is too big?

If you purchase a filter that's too large, it won't slide into the slot correctly. If the filter is too small, it won't cover the entire space and may allow dust and dirt to flow past.

can you cut a HEPA filter? These vent filters will stop a good amount of the larger particles that would normally clog a HEPA filter. For room air cleaners that don't have a pre-filter, some people cut a piece of the vent filter material and place in front of the HEPA filter. And no, this won't affect how quiet the air purifier is.

Keeping this in view, can I use a 4 inch filter instead of 5?

No way! You just need the right kind of high MERV filter. A thicker filter (4-5 inches) has more surface area and therefore allows more room for air to pass through. Do this: If you're really interested in keeping your air clean, we'd suggest you get an air cleaner/purifier installed in your air ducts.

How tight should an air filter fit?

The filters don't need to fit with an “air tight” seal, but you should be able to easily install and uninstall your filter without a struggle, plus the filter shouldn't be so small that it moves freely within your unit.

Related Question Answers

Guohua Gessert

Professional

Do Filtrete filters restrict airflow?

Because they restrict airflow to your HVAC system. Pleated, high-MERV filters definitely capture a lot of pollutants, but they also restrict the movement of air into your blower or furnace. These cover all the air filtration basics - dust and pollen removal, for example - without restricting airflow.

Gaspare Maraco

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Are expensive filters worth it?

More expensive filters like Pleated Residential filters filter out dust mites, pollen, mold and pet dander and even bacteria and so are worth the money especially for those with severe allergies. HEPA filters filter bacteria and viruses and are worth the extra money for those with respiratory conditions like emphysema.

Dorica Olaetxea

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Should I use MERV 8 or 11?

A MERV 8 filter should pick up most animal dander, but if you have 2 or more pets you may need a MERV 11 to completely eliminate those harmful particles from your home's air.

Suzi Goikoetxea

Explainer

What MERV rating do I need?

The MERV rating scale ranges from 1-16. Lower quality filters, in the 1-4 MERV range, are typically made of fiberglass. Most residential HVAC systems will use air filters with MERV ratings from 7-12. A higher MERV value of 5-16 would be recommended for commercial buildings.

Renay Opris

Explainer

Are MERV 11 filters too restrictive?

A decade ago, it used to be that if you had an HVAC system that used panel filters rated 6 through 9 MERV, putting in a MERV 11 or higher filter would restrict airflow (known as filter pressure drop). In turn, this would lengthen the system's run-time, adding to your heating and cooling costs.

Fidenciano Pleugner

Explainer

Is MERV 13 too restrictive?

MERV is a good way to help judge the effectiveness of an air filter. In some cases, using an air filter that is too restrictive for your system may cause low air flow problems as well. MERV 13 is the highest MERV value safe for residential furnaces; the higher ratings are used primarily in commercial units.

Zhilin Millor

Pundit

Is a thicker air filter better?

Most air filters are 1 inch thick, but some systems can accommodate filters 2 to 5 inches thick. In our tests, we found that the thicker the filter, the better it works and the longer the replacement intervals. That means it's better for you and for your HVAC system.

Diarra Redinha

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Can I use a 1 inch filter instead of 4 inch?

While a 4-inch-thick filter is more efficient than a 1-inch filter, the right size depends on your furnace. If you measure the filter slot, and it's large enough to accommodate the thicker filter, then you can use it. However, if the slot is less than 4 inches wide, you're stuck with using that thickness.

Kazuko Aboev

Pundit

Is a 4 inch furnace filter better than a 1 inch?

Well, 4-inch filters have larger pleats. That means they have more surface area to catch particles, making them last 3–5 times longer than 1-inch filters. Most HVAC technicians recommend changing 1-inch air filters every 30 days, while 4-inch filters can be changed every 3–6 months.

Manol Dúbhshlaine

Pundit

Do thicker furnace filters last longer?

Filter thickness: A filter's thickness can range from 1″ to 5″. As a general rule of thumb, a thicker furnace filter will last longer and can be more efficient.

Shuping Azouagh

Pundit

Does furnace filter size matter?

AC filter sizes will vary. Your air vent filter size should match exactly to slightly smaller than the measured outside length and width of the frame around that opening. Having an incorrect filter size is like not using a filter at all, which can have a bigger impact on your furnace and AC systems.

Nahiara Greihs

Teacher

Can I use a 1 inch filter instead of 5?

3M makes a magnetic adapter that allows you to use a 1 inch filter instead of 5 inch one.

Ora Klappacher

Teacher

Engracio Niklas

Teacher

What are standard air filter sizes?

The most common furnace filter sizes are 10 X 20, 14 X 20, 16 X 24, 18 X 30, 12 X 12, 14 X 24, 16 X 25, 20 X 20, 12 X 20, 14 X 25, 18 X 18, 20 X 24, 12 X 24, 14 X 30, 18 X 20, 20 X 25, 12 X 30, 15 X 20, 18 X 24, 20 X 30, 12 X 36, 16 X 20, 18 X 25, 4 X 24, and 25 X 25, and these sizes range in depth from 1 to 6 inches.

Ioachim Wiegant

Teacher

Nica Iravedra

Reviewer

What is the best air filter for home?

So here is my list of The 10 Best Furnace Filters.
  • AIRx Health 1" MERV 13 Furnace Filters.
  • Honeywell FC100A1037 Ultra Efficiency 4" Furnace Filters.
  • Nordic Pure 4" Furnace Filters.
  • FilterBuy 1" Furnace Filters.
  • AIRx ALLERGY 1" Furnace Filters.
  • Filtrete Micro Allergen 4" Furnace Filters.
  • X6673 Lennox 4" Furnace Filters.

Ibolya Bia

Reviewer

What does a HEPA filter do?

HEPA stands for high-efficiency particulate air. A HEPA filter is a type of mechanical air filter; it works by forcing air through a fine mesh that traps harmful particles such as pollen, pet dander, dust mites, and tobacco smoke.

Gener Juengling

Reviewer

What are HEPA filters made of?

The HEPA filters are made of borosilicate glass fibers or plastic fibers (e.g., polypropylene) bound together with up to 5% acrylic binder (the same compound that binds latex paint to a house).

Escarlata Klott

Supporter

What is HEPA material?

HEPA filter is an acronym for High-Efficiency Particulate Arrestance, and it is a type of air filter. They are composed of a mat of randomly arranged fibres. The fibres are typically composed of fiberglass and possess diameters between 0.5 and 2.0 μm.