Your question: How do you measure a furnace filter without a filter?

If you do not have an existing air filter in your furnace, or your existing filter does not fit properly, you will have to measure the duct opening. To do so, you will need a flashlight and a stiff tape measure.

How do I know what size air filter I need without a filter?

Actual Size: The actual size of an air filter is typically written in the fine print on the frame of the filter and is usually 0.25″-0.5″ smaller than the advertised, nominal size. The actual size is what you’d find if you used a ruler to measure the exact dimensions of the filter.

How do I know the size of my furnace filter?

The easiest way to find out what size filter to get for your furnace is to simply remove your current filter and look at its dimensions. These are typically printed along one of the sides of your filter.

How do I know what size air filter I need?

Follow these 3 easy steps to measure your HVAC filter size:

  1. Step 1 – Measuring Length and Width (L x W). (If your filter is not a square, the smallest measurement goes first).
  2. Step 2 – Measure the thickness (Depth) of your filter from front to back.
  3. Step 3 – Put Your measurements together (L x W x D).
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Are air filters measured in inches?

The dimensions listed on the side of air filter frames and printed largest on air filter packaging are normally the nominal size dimensions. These measurements indicate the length, height, and depth (thickness) of the air filter, rounded up to the nearest inch. An example of nominal dimensions would be 16” x 24” x 1”.

Do air filters have to be exact size?

Since air filters are most often sold by their nominal dimensions, it is crucial to learn how to properly measure your air filter. When making your purchase, you should order your filter by its nominal size, rather than its actual size.

Is it OK to run the furnace without a filter?

Technically, you can temporarily run a furnace without a filter. However, it’s important to emphasize the word “temporarily” here. … Poor air quality: For one, not having a filter in place means there is nothing to prevent dust and debris from being sucked into your furnace and recirculated throughout your home.

Can you cut furnace filters to fit?

Some manufacturers can even customize the filters for you to fit perfectly when you or your HVAC team puts everything together. Simply put, yes, you can cut an air filter if you know what you are doing, and if the filters you use will not become too weak from the cutting.

What happens if you use the wrong size air filter?

When you use the wrong size air filter, or you install it incorrectly, the filter can’t effectively prevent dust from accumulating on the system’s motors and blowers. You’ll end up with a dirty furnace that can’t properly perform, and all of that debris could end up harming the system’s internal components.

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What is a standard air filter size?

Standard air filter sizes include:

10X20 14 X 20 20X20
12X12 14X24 24 X 24
12X20 14X25 20X24
12X24 14X30 20X25
12X30 15X20 20X30

What is the most common size air filter?

What Are the Most Common Air Filter Sizes

  • 20 x 25 x 1.
  • 20 x 25 x 4.
  • 16 x 20 x 1.
  • 16 x 25 x 4.
  • 20 x 30 x 1.
  • 12 x 12 x 1.
  • 14 x 14 x 1.
  • 14 x 20 x 1.

How should a furnace filter fit?

How tight should a Furnace Filter fit? When you remove the existing filter, take note of the dimensions printed on its frame. Your new filter will need to match this size for the system to run efficiently. It should fit snugly but not so tight that you can’t easily slide the filter in and out.

Can I use a 1 inch filter instead of 4?

Question: Can i use a 1 inch filter instead of 4 inches? Answer: If you are okay with more frequent replacement and little stress on the system, 1” filter can be budget-friendly alternative of 4” filters.