Clear Signs It’s Time to Change Your HVAC Air Filters
  • Posted on December 11, 2023
  • By Rod Miller

Keeping your house feeling fresh and your air clean is often as simple as checking your air filter. If you’re unsure when to change your HVAC air filters, don’t worry—your home will give you some clear hints.

This article will go through those hints, from dusty rooms to weird smells, so you can keep your air system working well and your energy bills down. However, if you feel like air filters are not the cause of HVAC problems, Rod Miller is here to help you discover what is.

Changing your filter on time means breathing easier and staying cozy. Let’s uncover the tell-tale signs that your air filters need changing.

The Simple Rule of Regular Filter Replacement

Most air filters in your home, like the thin fiberglass ones or the ones that catch allergens, need to be swapped out every three months. These are your everyday filters that do a good job of keeping stuff like dust, hair, and the bigger bits of floating junk out of the air and off your furniture.

Now, if you’ve got a HEPA filter, that’s like the big boss of air filters. They are made to trap tiny particles, things you can’t even see, like bacteria and tiny dust mites. Because they’re really good at their job, you don’t have to change them as much. They can go for about half a year to a full year before they need changing.

It’s all about balance. Think of your air filter as a trash can. If you toss only a few things in, you don’t need to empty it so often. But if you’re throwing away a lot, you’ll need to empty it more often so it doesn’t start to smell or overflow. It’s the same with your air filter – if your home is dusty, you have pets, or you run your HVAC a lot, you might need to change the filter more often. If you need to change it before your scheduled change, you will probably see some signs, such as cold air while heating or foul odors. 

Your Heating System Blows Cold Air

When your heater is blowing cold air, a dirty air filter could be causing trouble. An air filter is meant to catch dust and keep the air clean. But when it gets too dirty and clogged, air can’t get through as easily.

Think of it like trying to breathe with a cloth over your mouth; it’s tough, right? Well, your heater feels the same way with a clogged filter. It needs air moving through to keep its insides, called the heat exchanger, from getting too hot. If not enough air gets through, the heater might turn off the flames to avoid damage from the heat. But the fan keeps going, blowing cold air instead of warm.

Change your HVAC air filters, and air will move freely again. This keeps everything inside the heater cool enough to work right and keeps your house warm. If changing the filter doesn’t stop the cold air, then the problem might be something else, like a broken part or a setting that’s off. That’s when you might need help from the professionals. 

Foul Odors and Your Air Filter

Foul odors coming from your HVAC system can be unsettling and are often a clear sign that your air filter may need attention. Here’s how this happens:

Imagine your HVAC system as the lungs of your home, circulating air throughout the space. Now, when your air filter is clean, it captures various airborne particles, preventing them from recirculating. However, when the filter becomes saturated with these particles — everything from common dust to more odorous contaminants like pet odors, cooking smells, or tobacco smoke — it can begin to emit a foul stench.

As the air continues to pass over a dirty filter, it can pick up these unpleasant smells and spread them throughout your house. This is especially true if moisture is involved, as a damp filter can become a breeding ground for mold and bacteria, which produce a musty or even sour scent.

If you start to notice a persistent bad smell when your heating or cooling system kicks in, it’s wise to first check the air filter. A quick inspection may reveal a buildup of debris and odor-causing culprits. Replacing the old filter with a new one can help to eliminate these odors, as the clean filter will better trap contaminants, ensuring that the air circulating through your system, and subsequently your home, is fresh. 

Are your Energy Bills Rising? 

A rise in your energy bill can often signal that it’s time to check and possibly change your air filter. A dirty filter will make your HVAC system work harder to push air through the blocked filter. The harder your system works, the more energy it uses, leading to higher energy bills. This prolonged operation not only uses more energy, raising your bill but also adds wear and tear to your system, potentially leading to costly repairs.

So, if you notice that your heating or cooling costs are climbing and you haven’t been using your system any differently than usual, it’s a good idea to check your air filter. If the filter is gray and dirty, replacing it with a clean one can help your system operate more efficiently, saving you money on energy costs in the long run.

Increased Dust as a Red Flag

Your air filter’s job is to catch dust and stop it from blowing around your house. When the filter gets full of dust, it can’t trap any more. That means instead of getting caught in the filter, dust just keeps on floating through the air and settling on surfaces in your home.

More dust can also mean that bits are getting into your heating system, which isn’t good for it. All that gunk can make parts wear out faster and can stop the system from working as well as it should. It can even send some of that dust back into the air through the vents if it gets really bad.

So, when you see more dust than usual, it’s time to take a look at your air filter. If it’s covered in dust and looks gray instead of white or whatever color it was when it was new, it’s time to swap it out for a fresh one.

Keeping a clean filter in there helps keep the dust down in your house and helps your heating system do its job better. Plus, it’s a pretty easy fix to keep you healthy and your home feeling fresh.

More Fur, More Frequent Filter Changes

When you have pets, fur and dander are just part of life. But they’re also things that can clog up your air filter pretty fast. Pet fur can gather on the filter, blocking the airflow just like dust does.

If you’ve got furry friends at home, you’ll probably need to change your HVAC air filters more often. Try to look into their state every 30 to 60 days. So, keep an eye on your filter and change it regularly, especially when pets are around. This way, you’ll keep your air cleaner and your heating system happy. Plus, it’s a simple way to help reduce allergies and keep your house feeling fresh.

Air Quality and Increased Allergy Symptoms

Sneezing, itchy eyes, and a runny nose getting worse when you’re indoors? It might be your home’s air filter waving a white flag. If it’s been a while since the last change, the filter may be struggling to perform its role efficiently. A clean air filter efficiently cycles the air, reducing the amount of airborne allergens. However, once it becomes clogged with debris, its effectiveness diminishes, and more allergens remain in the air.

As these irritants accumulate, they can aggravate allergies more than usual. If you’re noticing an uptick in allergic reactions, your indoor air quality might not be good. This is a strong indication that your air filter isn’t keeping up with removing those irritants from the circulation. Swapping out the old filter for a new one can make a noticeable difference. With a fresh filter, you should find that the air feels fresher, and allergy symptoms may lessen as a result.

Frequent Cycling as a Sign to Change Your HVAC Air Filters

Frequent cycling refers to when your HVAC system turns on and off more often than it should. It’s like your system is trying to keep pace, but something’s making it trip up. When the air filter is dirty, it’s a bit like putting a blockage in a running track — the system has to work harder to get air through. It starts and stops, trying to push air and reach the set temperature, but the clogged filter makes it tough.

This stop-and-go operation is not only annoying; it’s also a sign your system is working inefficiently. It can lead to wear and tear on your HVAC components and potentially shorten the lifespan of the system. Plus, this inefficiency can hit your wallet, as the system uses more energy each time it has to start up again.

Change your HVAC air filters to smooth out this cycle. It allows the system to have a more steady, efficient run without the strain caused by trying to pull air through a clogged filter. 

After replacing the filter, the system should return to a normal cycle, running less frequently and maintaining the temperature more consistently.

Hopefully, you are now ready to see the signs you need to change your air filters. In order to make your HVAC system work properly for years, it is important to schedule maintenance with professionals once in a while. With help from our Rod Miller team, you can be sure everything is working properly. 


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