Calendar icon February 6, 2023

Air Filter Sizes & How They Work

Photo of Alec Lower

Alec Lower

Social Media Coordinator - Second Nature

What is an undercut? What does nominal mean? All the answers are right here.

 

One of the more needlessly confusing elements of home wellness is air filter sizing. We didn't make it this way, but we are making it is as simple as possible for you right here. Let's get started.

‍

The two types

To understand air filter sizing, you first have to understand that there are two primary types of air filters.

‍

  • 1-inch and 2-inch air filters
  • Whole house air filters

‍

Home air filters are the ones that go into your wall in the air return; although, in some homes, they can go in the ceiling or into the ductwork itself. Your "air return" is aptly named—it's where "air returns" to your HVAC system from inside your home. Most filters for your return are 1" thick. While 2" filters are found in some homes, it's a lot less often.

‍

Whole house filters usually go into an air handler, which is typically situated next to your HVAC system itself. In some homes, these go directly into the ductwork too. It's worth noting that, while you usually only have one, it's possible to need more than one whole house filter for your home. Whole house filters always have a thickness of 4, 5, or 6 inches.

‍

You may have noticed that we did not mention 3-inch filters. While 3" filters technically do exist, they're particularly rare. If you need a 3" filter, you are special.

‍

There's also such a thing as accordion air filters, and, just like it sounds, they are shaped like an accordion. If you have one of these in your home, we sell those too, but...well, that's just weird.

‍

Air Filter Sizes: Length and width

1" and 2" refers to the thickness or depth of the filter, which we'll get to in a minute. First, let's talk about length and width. Length and width are technically interchangeable, but for discussion purposes, a 12x20 is 12 inches long and 20 inches wide. It's a very common size that is easy to find, and it's on a short list of sizes that are common enough for air filter companies like us to keep in stock. Some other common sizes are:

‍

‍

If you have a 1" or 2" air filter that is not on this list, you'll likely need a custom cut, and the hardware store definitely can't help you here. We've got you covered, though. With our custom air filters, there are 66,000 possible different sizes. We know! That's a lot.

‍

To put 66,000 in perspective, that's roughly the population density of Manhattan per sq mi. That's also approximately how many Orangutans are alive today. Take those facts to trivia.

‍

Undercuts and roundings

A 20x20x1 air filter is actually 19-¾" x 19-¾" x ¾". This is what is known as the undercut. All 1" and 2" filters are undercut by a quarter of an inch to provide a little bit of leeway to ensure it fits into the air return without being too big. This includes custom sizes, so a 27-⅜" x 23-⅝" x 2" (which is the weirdest size we could think of) is actually 27-⅛" x 23-⅜" x 1-¾".

‍

At SecondNature.com, you'll see an actual size that shows the undercut when you enter a custom size. You'll want the custom size you pick to be the size of your return measurements, which allows the actual size to be a quarter-inch less.

‍

Undercuts exist on whole house filters as well, but not in the same way they do for 1" and 2" filters. In fact, undercut is a bit of a misnomer when it comes to whole house air filters. These are actually just rounded to whole numbers in a somewhat arbitrary fashion. Allow us to explain.

‍

Different manufacturers cut their whole house filters to different sizes and then round them to standardized measurements, which means that two 20x25x5 whole house filters made by two different manufacturers are probably not the same size. Below are some examples:

‍

  • Honeywell has a 20x25x5 is actually 19-3/4" x 19-7/8" x 4 3/8"
  • Filtrete has a 20x25x5 is actually 19.75" x 24.4375" x 4.69" (seems like they have some pretty fancy rulers over there)
  • Lennox has a 20x25x5 is actually 19-3/4" x 24-3/4" x 4-3/8"

‍

And that all makes total sense...?

‍

Because of this, it's necessary for those of you that need a whole house filter to know the exact filter size you need. If you can't find that on the filter, you can provide Second Nature with the nominal size and the brand that you had previously been using, and we'll be able to find the filter you're looking for.

‍

Nominal vs. Actual size

All filters are sized two different ways. Yep, you read that correctly. All filters have an actual size and then a nominal size. The actual size is the exact dimensions with no rounding; whereas, the nominal size is the rounded dimensions of the filter. This means that on 1" and 2" air filters, the nominal size does not include the undercut, and the actual size does include the undercut. On whole house filters, the nominal size is the rounded size, and the actual size is just the unrounded. Pretty easy stuff here.

‍

Sizes can be reversible

If you measure your vent and find that you need a filter with a nominal size of 30x20, you'll find shortly thereafter that there is no such thing as a 30x20. There is only a 20x30, and that is what you actually need. Whether the pleats on the filter run horizontally or vertically won't impact the effectiveness of your filter, so the number of unique air filter sizes on the market can simply be cut in half by always listing the smaller measurement first instead of having a 20x30 and a 30x20 as two completely different products. If you find that you need a 15x34, grab yourself a 34x15 and just rotate it 90 degrees. It's the same thing.

‍

And that's how air filter sizes work. It's probably a little more complicated than it needed to be, but we try to make it easy. Now you'll never be confused by things like undercuts again.

‍

tl;dr: air filters have weird sizes. Leave the rest to us—we'll make sure the right ones get to you right when you need them.

‍refrigerator water filter reduces.

Topics:

Homeowner Insights

More articles

Keep learning

The Good and The Bad of Virtual Property Management

Scott Hampton, who founded Hampton and Hampton with his wife in 2004, has seen the continued growth of the rental proptech sector over the last 20 years. With virtual becoming a buzzword in basically every industry, property management included, Hampton and Hampton has had to challenge some its preheld notions about the industry and learn how to best leverage virtual processes in the business. There are good parts and bad parts of an increasingly virtual world, and Hampton was kind enough to share his experiences trying to navigate this. Virtual showings One area where Hampton has committed to the benefits of a virtual approach is in showings. The rise of the virtual showing during COVID changed quite a bit for Hampton and Hampton, and Scott was very honest his old-school nature creating some qualms about the process, but the benefits were real as well. “Before COVID, people were still uncomfortable,” says Hampton. “They wanted someone to show up and shake their hand and open the door. Now, people are perfectly fine with getting a code on a code box. And I can sit on a Zoom call or Google Meet call with you on my phone. I can do it on a laptop.” The flexibility is really the big win with virtual showings. The logistical burden gets lifted quite a bit. The concept may not have unpopular in the past with prospective residents, but Hampton has seen a shift in how open renters are to more virtual processes. “I've seen our staff show houses on their phone at lunch and just walk the people through the house, literally, anywhere they're at and the people are fine with that. And then obviously just send them a link for the application and do everything digitally for that right there and to grease the skids as I say, to make that transaction as easy as possible for them. So you know, I think virtual showings have been a huge change for us.” While there are drawbacks to virtual showings that Hampton will touch on, the win here for the PMC is ease of logistical management. You no longer have to get an agent to a place and coordinate that. It just helps remove so much of extra legwork. "Logistically, it's hard when you're in two cities," says Hampton. "Even though you have staff in two cities, it's still logistically difficult to do that, to coordinate those things and to get that many people around. So that's helped." Virtual Assistants A lot has gone virtual over the last four years, for better or worse, and the geographic reach of the hiring companies has seen some of the biggest change. This virtual outsourcing has helped Hampton and Hampton be more efficient in the post-sales process, which in turn allows their salespeople to be more efficient and do the things they are more cut out to do. “We now work a lot more with virtual people. Not virtual companies per se that are out there, but currently, we have more virtual folks that are more like sales agents that are in other cities. They write contracts for us. They handle closings. I've never met some of our virtual closing people. They literally are US-based real estate agents and they write the contract they get handed the contract once it goes, they go to get the inspections done, and they get the financing in place. So the salespeople can kind of just move on to another sale and not be bogged down dealing with, you know, did the inspection get done today? Did the electric get turned on? And so we do a lot more with that." Drawbacks of Virtual Property management will also be a people business. Good PMs understand optimizations and processes built on tech is not a golden ticket. Relationships matter, and one of the drawbacks of a more virtual world is the spiking difficulty of managing relationship. "That's really hard to do," says Hampton. "It's just really hard to to convey that to people. I used to know the tenants' names and they used to know me. I rented them the house and, you know, I knew their boys. Same with the clients. I used to know their voice, but you lose that touch. So it's very hard and that's the one thing too that I think we all lose is that personal touch of a human relationship."

Calendar icon June 27, 2024

Read more

Why Pest Control Is Important for Property Management

Pest control plays a critical role in effective property management. That's because pests are not just a nuisance – they can also contaminate food, damage belongings, spread diseases, and make rental properties unlivable. In this blog, we'll cover the impact of pests on your property and residents' lives, practical strategies for controlling these unwanted guests, and the benefits of a preventive approach to pest management. On hand to help us deliver these insights is Landon Cooley, the Co-Founder and CEO of Pest Share, a commercial pest control expert. Cooley's extensive experience in the pest control industry provides valuable knowledge on how property managers can effectively integrate pest control into their maintenance routines. What you'll learn: Why preventive pest control is a smart strategy How to monitor and control pests on your property The responsibilities of property managers and residents in maintaining a pest-free environment Common pests, how they enter properties, and the importance of immediate action and resident education By the end of this article, you’ll have a thorough understanding of the importance of pest control in property management and actionable steps to ensure a healthy, comfortable living environment for your residents. Why Preventive Pest Control Is a Good Strategy The most important part of pest control? Prevention. There are so many reasons that a good preventive pest control program can pay off for your company, your investor, and your residents. It sets professional property managers apart from the crowd. Here are some of the top reasons why preventive pest control works. Cost-effective in the long run Investing in a preventive pest control plan can save significant costs in the future. While there is an upfront cost, it's generally far less than the expense of handling large-scale infestations or property damage caused by pests. Prevents major infestations Pests have a way of multiplying exponentially. A preventative approach can nip potential critter nightmares in the bud. By treating small issues promptly, you can prevent them from developing into major infestations that are difficult and costly to eradicate. Enhances resident satisfaction Preventive pest control contributes to a comfortable and healthy living environment. By keeping pests at bay, you increase resident satisfaction, which can lead to longer tenancy periods and positive word-of-mouth referrals. Preserves property value Pests can cause significant damage to the structure and aesthetics of your property. By keeping properties pest-free, you protect and preserve the value of the property. Property managers are, in the most foundational way, asset managers for their property owners. This is a critical way to protect those assets. Reduces health risks Many pests carry diseases that can pose health risks to your residents. A preventive approach to pest control helps maintain a healthier living environment by reducing these risks. It also protects you and your investor from liability associated with those health concerns. Maintains reputation Effective pest control is a key aspect of property management, and a preventative approach helps maintain a good reputation. It shows prospective and current residents that you are proactive and dedicated to providing a safe, comfortable living environment. Again, prevention sets you apart from hobbyists and amateur property managers. How to Monitor and Control Pests in Your Property Regularly scheduled inspections are the best mechanism for effective pest monitoring. Ideally, qualified personnel should conduct quarterly or biannual checks. These inspections will focus on identifying potential entry points for common pests, and might include checking for cracks in the foundation, gaps around pipes and wires, and proper ventilation in crawl spaces. Maintaining open communication with residents is equally important. Encouraging residents to report any signs of pests, like droppings or unusual noises, allows for early intervention. Property managers should have a clear procedure for responding to such reports, ensuring a swift and effective resolution to prevent infestations from escalating. Of course, understanding the problem only gets us halfway (if even!) to solving it. As property managers, the responsibility of dealing with pest issues falls squarely on your team’s shoulders. Great property management companies employ a strategic approach to integrated pest management (IPM), minimizing the possibility of pests – and dealing with them immediately when there’s an issue. Along with routine inspections, here are some of the top property management pest control trips we’ve handpicked from the industry. Immediate action Taking immediate action at the first sign of a pest problem is crucial. Delays can allow the pest population to grow, making the issue more difficult and costly to handle. A quick response to reported issues shows your residents that their comfort and safety are a priority and can often prevent minor issues from escalating into serious infestations. Whether you call an exterminator or handle it in-house, a swift response is key. Tenant education Educating tenants on proper food storage and waste disposal can drastically reduce the attractiveness of your property to pests. Regular communication about cleanliness and preventative measures empowers residents to contribute to a pest-free environment. Professional pest control services Sometimes, professional intervention becomes necessary. Pest control services can effectively deal with large infestations, employing safe and targeted solutions. They can also provide expert advice on preventing future infestations. When hiring pest control companies, Cooley says, it’s important to understand what types of specializations they offer. “There are several different segments of the industry, and not all companies do everything,” he says. “Some do only residential insect control, or maybe rodent control. Some are very robust and specialize in all these areas. Every company is a little different.” Landscaping and exterior maintenance Maintaining the exterior of your properties is as crucial as looking after the interior. Regularly trim overgrown plants, manage water drainage effectively, and keep outdoor trash areas clean to deter pests. Seal entry points Prevent pests from entering by regularly checking for and sealing any potential entry points. This includes filling cracks, fixing broken screens, and covering crevices. Keeping your property in good repair helps make it less accessible to pests. Proper waste management Secure and timely waste disposal is key to pest prevention. Ensure that all trash bins are properly covered and regularly emptied to avoid attracting rodents, insects, and other pests. Each of these methods contributes to effective pest control, helping to create a comfortable, pest-free environment for your residents. Property Management Pest Control Concerns Who is responsible for pest control? The responsibility for pest control can vary depending on the state and the specific situation. In many states, landlords are largely responsible for maintaining a habitable dwelling, which includes addressing existing pest infestations and taking preventative measures. However, some states place more responsibility on residents, especially if the infestation arises from unsanitary conditions within the unit or from a tenant's actions that attract pests. Lease agreements often address pest control by outlining each party's obligations. It's important for both property managers and tenants to understand these clauses to avoid confusion or disputes. What are the most problematic pests? In terms of structural damage, termites and rodents are high threats due to their ability to gnaw and burrow. Ticks pose significant health risks as they can transmit diseases. For general nuisance and quality of life issues, cockroaches and bedbugs are common culprits. Ultimately, the most problematic pests will depend on the specific location, property type, and potential health risks. Do I need preventive pest control? If the properties you're managing have historically had pest problems, or are situated in an area with frequent infestations, then proactive measures will certainly be beneficial. Regular inspections and preventative treatments can offer peace of mind and potentially save money by stopping infestations before they start. Even if you haven’t had any issues, a purely reactive approach can end up costing you. How can pests enter my property? Pests can enter properties in a surprising number of ways. Cracks in foundations, gaps around windows and doors, holes created by utility lines, and damaged vents are all potential entry points. Even seemingly small openings can be enough for some persistent pests, like rodents and insects. Additionally, pests can hitchhike inside year-round on cardboard boxes, used furniture, or on pets. Why Pest Control Is Important When we talk about property management, pest control isn't just an afterthought—it's a crucial component of providing the peace of mind that comes with a safe and comfortable living environment. Dealing with these “visitors” is important beyond just the ick factor. “The pest control industry only serves 15% of US residents, and yet 86% of US residents have an experience of pest infestations every year,” Cooley says. “So there’s a big gap.” Let's delve into some of the key reasons why pest control is so important. Pests contaminate food Many pests, such as cockroaches, ants, and rodents, are notorious for finding their way into food supplies. They can carry harmful bacteria and other pathogens, contaminating food and cooking surfaces. Mouse droppings, for example, can spread disease, in addition to just being … gross. This can potentially lead to foodborne illnesses amongst residents, causing unnecessary discomfort and potential health issues. Pests destroy property Pests like termites and carpenter ants can cause costly damage to the property structure, eating away at wood and compromising the integrity of the building. Other pests may gnaw through electrical wiring or insulation, leading to costly repairs. By maintaining consistent pest control measures, you can prevent such destruction and safeguard your property, making it a more secure and stable environment for your residents. Pests destroy residents’ belongings Some common pests, like carpet beetles or silverfish, may seem small and harmless, but they can wreak havoc on a resident's personal belongings. These pests can destroy everything from clothing and books to upholstered furniture, causing financial stress and discomfort to your residents. Pests spread diseases Pests are known carriers of a variety of diseases and can be a public health risk. Rodents can spread hantavirus and salmonella, mosquitoes transmit West Nile virus and Zika virus, ticks carry Lyme disease, and fleas are known to carry several diseases or allergic reactions, to name a few. Roaches carry any number of bacteria and diseases. Keeping these pests at bay is critical to maintaining the health and well-being of your residents. Pests make it difficult to live Beyond physical health risks, pests can create an uncomfortable, even distressing, living environment. The presence of pests can lead to anxiety and sleep disturbances, negatively affecting residents' quality of life. Pests like fleas and bedbugs cause physical discomfort if not outright health problems, and many pests, like mites, spread or trigger allergens. In short, effective pest control is essential to maintaining the integrity of your investors’ property assets, the health of your residents, and your reputation as a caring and responsible property manager. How Much Does Pest Control Cost? The last, and sometimes biggest, hurdle when it comes to pest control? Cost. General pest control methods can cost hundreds of dollars per service. Here’s an average breakdown for budgeting purposes: Cockroach/flea treatment: $350-$750 per service Bed bug treatment (heat): $1500+ per service Bed bug treatment (chemical): $1000+ per service Rodent trapping service: $250+ per service Quarterly general insect service: $40-$50 per month How can property managers find a cost-effective solution that drives value and comfort for their residents without breaking the bank? Throughout his years of experience, this is the question that Landon Cooley found was nagging the property managers he met. “We wondered: Can we take these specific pain points – bedbugs or cockroaches or fleas – and find a solution that we can build into our Resident Benefit Program?” Property Management Pest Control Solutions Cooley’s solution? He co-founded Pest Share, which is a new service in Second Nature’s fully managed Resident Benefits Package. The Pest Share model is a subscription model that works like a co-op: everyone pitches in, and the collected funds go to the more expensive parts of the plan without burdening any one client with too much cost. Property managers simply select the Pest Assurance plan from four tiers of service levels. They add that plan to their RBP or OBP and pay a flat rate for it, which they can also roll into their overall RBP ancillary fees. Their residents can then go directly to Pest Share on their mobile phones to get pest services for no cost. “What we’re offering is unique, on-demand, and very tech-forward. Pet Share gives quick access to service but allows us to offer cheaper price points for the same end result,” Cooley explains. “Our approach is, 'How can we take this off the property manager’s plate?’ We aim to create ancillary revenue for them, take an annoying task off their list, and enhance the resident experience.” The result? Pest Share has helped their property management clients increase their Benefit Package ROI by 75%. For Second Nature, including Pest Share’s model in our Resident Benefit Package – and upcoming Investor Benefit Package – was a no-brainer. Learn more about Pest Share by getting in touch, or read our latest study on the impact of our RBP on the resident experience.

Calendar icon June 24, 2024

Read more

Receive articles straight to your inbox

Deliver the ultimate resident experience

Our Resident Benefits Package gives residents everything they want without all the work.

Get a demo