Most homeowners grab whatever air filter is on sale and call it done — but that habit could be quietly damaging your HVAC system and driving up your energy bill. This video cuts through the marketing noise and walks you through the three things that actually matter when choosing an air filter: the recommended merv rating for residential ac filter, surface area, and structural integrity.
What you’ll learn: You will walk away knowing exactly which MERV rating balances clean air with system efficiency, why pleat count matters even when the filter size is fixed, and why a structurally weak filter can cause expensive A-coil damage that most homeowners never see coming.
What most people miss: The instinct to buy the highest MERV rating available is wrong — a filter that is too restrictive makes your furnace work harder, wear out faster, and actually run less efficiently, costing you more money in the long run.
Why it works: The host uses a manometer to measure real pressure drop across filters with different pleat counts, and tests filter rigidity by running brand-new filters in his own furnace — showing on camera which ones buckled and let air bypass the media entirely.
Watch for the moment when a brand-new filter buckles inside a running furnace, letting unfiltered air flow straight up into the A-coil — it is the kind of thing you cannot unsee, and it will change how you shop for filters forever.
Key Moments: What to Watch For
Click any timestamp to jump to that moment in the video.
- ► 1:32 — “Higher is not always better. Your furnace or air handler system has to draw that air through the filter. When you have a very restrictive air filter, it causes a lot of stress on the system, which can lead to early wear of some components.”
- ► 2:04 — “If you take a very small straw like this one, place it in your mouth and try to draw air or liquid through it, it’s quite difficult to do — versus if I take a larger straw and do the same thing, it’s significantly easier to draw air through.”
- ► 3:33 — “The filter I use in my own furnace is a MERV 10, and it has 21 pleats. This other MERV 10 that I picked up at the store as a demonstration only has 17 pleats. The fewer number of pleats gives it less surface area if you were to spread them out and compare them.”
- ► 5:37 — “If dust, dirt, debris, hair flows through the system and into that A-coil, it will block off the air flow, giving you significantly reduced efficiency on your air conditioning system, costing you more money.”
- ► 6:42 — “I actually had a brand new one buckle and bend, letting air go around it. While these are brand new, I can tell you I will not use them in my furnace.”
How to Choose the Right Furnace Air Filter: MERV Rating, Surface Area, and Structural Integrity Explained
The Moment That Makes You Think About Your Filter
There you are sitting in your living room enjoying yourself, sun shining through the window, and suddenly you see dust particles floating through the air and it makes you think — when was the last time I changed my furnace filter?
The three things we’re going to cover in this video — that is all you need to pay attention to when choosing an air filter — include the MERV rating, the surface area, and the structure or construction of the air filter. Let’s jump right in.
Why the MERV Rating Is the First Thing to Check
As you go to choose an air filter, ignore all that marketing. The number one thing I want you to pay attention to is the MERV rating. MERV rating stands for Minimum Efficiency Reporting Value, which is simply an easy way to quantify how good this filter is compared to the next one at filtering out different sizes of particulates.
MERV rating is created by ASHRAE, which is the American Society of Heating, Refrigeration, and Air Conditioning Engineers. The first thing you need to understand is the higher the number, the greater the efficiency or filtration you’ll have.
For example, here I have a MERV 10 and a MERV 8. The 10 is going to filter out not only more particulates, but particulates of a smaller size. You’ll see MERV ratings anywhere from one all the way up to 20.
Why a Higher MERV Rating Is Not Always Better
In your mind, you’re probably thinking, I’m going to get the highest one I possibly can to give me the cleanest air possible. And while that thought is good, higher is not always better.
While yes, it will clean the air, the other thing you need to keep in mind is your furnace or air handler system has to draw that air through the filter. When you have a very restrictive air filter, it causes a lot of stress on the system, which can lead to early wear of some components. It also minimizes the air transfer through the system, making it run longer and actually be less efficient from an energy perspective.
The Straw Analogy: Understanding Filter Restriction
To give a different representation of the stress that filters put on the system, think about different sizes of straws. If you take a very small straw like this one, place it in your mouth and try to draw air or liquid through it, it’s quite difficult to do.
Versus if I take a larger straw and do the same thing, it’s significantly easier to draw air through. So again, higher number is not always better. Choosing an air filter is very much a balance of clean air while not causing excessive stress on your system.
What MERV Rating Is Right for a Typical Home
A common residential filter is going to be a MERV 7 or a MERV 8. That’s very much going to reduce the stress on your system. If you’re like me, I do like to have slightly cleaner air, so I prefer to use something higher like a MERV 10.
I would ask you to get up right now, pause this video, go down, look at your furnace filter, and see what MERV rating it is and drop it in the comments below. I’m very curious to see what viewers out there are using.
Why Surface Area Matters Even When Filter Size Is Fixed
The next key point to talk about is surface area. When you go to buy a filter, your furnace is going to require a specific size — in my case, a 16 in x 25 in x 1 in filter. So why does surface area matter, and how can I change it if I’ve got a specific size of filter?
The greater the surface area, the more opportunity for air to flow through, and the less resistance there’s going to be of air flowing through the filter. It’s very challenging to change a filter size without an HVAC professional to come out and adjust your filter box. However, there are things you can pay attention to as a homeowner.
How Pleat Count Controls Surface Area
With a fixed size of filter, the only way to increase the surface area is by changing the number of pleats that are in the filter. The filter I use in my own furnace is a MERV 10, and it has 21 pleats. This other MERV 10 that I picked up at the store as a demonstration only has 17 pleats. The fewer number of pleats gives it less surface area if you were to spread them out and compare them.
Here’s a quick demonstration showing the pressure drop across these filters using my manometer to show you that it’s not only just MERV rating that makes a difference, but also the surface area of that filter. These filters that I like to use — when I measure with my manometer to check the pressure drop across the filter — it’s still pretty high and I don’t particularly like it.
The manufacturer filter that I like to use now has what’s called a mini pleat 1-inch filter, which increases the number of pleats greater than what I’m currently using, which will increase the surface area and reduce that pressure drop across that filter.
The Filter Brand Worth Knowing About
These filters that I use I actually buy from Amazon. It’s a company called Nordic Pure, which is a very well-known company for creating filters. Again, the name of the filters really don’t matter because it’s all about the MERV rating and that efficiency. I will drop links down below in the description so you can see what it is that I’m using and the different options they have compared to what you see at a store and what’s in your furnace today.
Why Structural Integrity Is the Most Overlooked Factor
The third item I want to talk about — which is the structural integrity of the filter — is one of the most important for preventing other issues with your system, specifically up in your air conditioning A-coil. Most people are going to say that an air filter cleans the air to give you, the human, the best breathing opportunity. And you’re right. But the other thing to remember is with air conditioning there is what we call an A-coil that is sitting above the blower in your furnace after that filter.
It’s important that clean air goes up through that A-coil because if dust, dirt, debris, hair flows through the system and into that A-coil, it will block off the air flow, giving you significantly reduced efficiency on your air conditioning system, costing you more money.
What Happens When a Filter Twists or Bows
Why is filter structure so important? I need that filter to stay rigid and in place and stop all those particulates — let the air go through the filter media, not around it. One of the main reasons I’ve used these Nordic Pure filters for a long time is they’re very structurally stable. They have bracing on both sides and they just don’t twist, compared to this other DuPont filter I picked up at the store that has bracing on just one side and is significantly less stable.
When you get increased restriction on a filter like this and it twists or it bows, air and debris can get around that filter up into that A-coil and get stuck, causing you more maintenance and bigger expenses. These particular filters are so flimsy that when I put them into my furnace and ran it, I actually had a brand new one buckle and bend, letting air go around it. While these are brand new, I can tell you I will not use them in my furnace.
The Three-Point Recap Before You Buy Your Next Filter
When you’re going to buy an air filter, ignore all the marketing. Step number one, pay attention to the MERV rating. Number two, to reduce that stress on your system, increase the surface area of the filter. And number three, commonly overlooked, get one with good structural integrity.
Go find your furnace, remove your filter, and take a look and see what the MERV rating is. Let me know in the comments below. Since we’re on the topic of HVAC, you might also check out the videos on air conditioner maintenance to keep yours running at peak efficiency to maximize cooling and minimize energy usage, which costs you less money.
Thanks for tuning in and learning about air filters with me. I’m James with Learn from Dad. Stay curious, friends.
Choosing an air filter is one of those small decisions that compounds quietly over time. Get it right and your system runs efficiently, your A-coil stays clean, and your air quality improves without wearing out your blower or spiking your energy bill. Get it wrong and you may not notice the damage until you’re staring down a repair bill or a clogged coil that has been slowly suffocating your AC all summer.
The best first step after watching this video is simple: go pull your current filter right now and check its MERV rating and pleat count. If it is a flimsy, single-sided filter with fewer than 20 pleats, that is your signal to upgrade. Look for a mini pleat option with bracing on both sides — something rigid enough that it will not bow when the system is running under load.
Once you understand what actually matters — and now you do — the recommended merv rating for residential ac filter decision becomes straightforward. Land somewhere in the MERV 8 to MERV 10 range, maximize your pleat count within your fixed filter size, and never put a flimsy filter in your furnace again. Your A-coil will thank you for it.