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.
Does an air filter have to fit perfectly?
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.
How do I know what size air filter to buy?
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.
Can an air filter be 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.
Is it OK to use a smaller air filter?
An improperly sized air filter doesn’t do its job. When it’s too small, it lets dust, mold, and other contaminants into your air vents. These then spew into your air, providing air quality problems.
What size air filter do I need without a filter?
Follow these 3 easy steps to measure your HVAC filter size:
- Step 1 – Measuring Length and Width (L x W). (If your filter is not a square, the smallest measurement goes first).
- Step 2 – Measure the thickness (Depth) of your filter from front to back.
- Step 3 – Put Your measurements together (L x W x D).
What is the most common air filter size?
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 do I know what size filter I need for my furnace?
Furnace filters are sized by width, length and thickness. The size on the filter is usually expressed in inches (example: 16″x20″x1″). A filter that is the wrong size will typically not fit, or may not stay in place, once installed. The owner’s manual for your furnace should tell you what size you need.
What MERV rating air filter should I use?
In general, the best MERV rating for a home is somewhere between 8-10. These filters will capture a large portion of the airborne particles and improve indoor air quality without making your energy costs rise significantly.
What happens if you have the wrong size air filter?
The biggest concern when you use the wrong size air filter is that it may not effectively prevent dust from building up on your HVAC system’s motors and blowers. This dirties up your furnace which could affect its performance or possibly harm the system’s internal components, leading to costly repairs or replacements.
Does filter size matter?
All elements are not the same. Some filter media is much better at flow than others, but can still trap the same size particles. Finding the right size filter for an engine takes in all these factors, as well as the intended usage, and service intervals.
Do furnace filters have to be exact size?
Your filter or HVAC unit should have both the nominal and the actual size written on it. If you can’t find the actual size, it’s a good idea to measure it just in case. Our website categorizes filters by the nominal size, making it easier to navigate and find your filter.
What happens if you put the wrong size filter in your furnace?
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.
Does the arrow point up or down on an air filter?
Air filters have arrows printed on the sides of them that show you which way they are supposed to be installed. These arrows should be pointing in the direction that air flows through your system, which is away from the supply ducts and (typically) toward the blower.