How To Keep Bugs From Coming In Through Air Conditioners

A dirty air conditioner after many years of bugs coming in

The thought of bugs crawling through your air conditioner is rather unpleasant. But many homeowners aren’t sure if this is actually something they need to worry about or not!

This guide will teach you why bugs sometimes come in through air conditioning units, as well as how to keep them out.

Can Bugs Crawl Through An Air Conditioner Into Your Home?

Your air conditioner is supposed to create a cool oasis that provides solace from the summer heat. So, you might be shocked to find some creepy crawlies making their way through your AC unit.

Unfortunately, bugs can crawl through your air conditioner to get inside your house. This surprise infestation is most likely to occur with both portable and window air conditioning units.

Quick Tip: Technically, bugs can crawl through the openings around ductwork or mini-split plumbing. However, the access points are far more prevalent on smaller systems.

Even if your AC looks adequately installed, there’s a good chance that it’s not perfect. Whether you have a portable rolling unit or one that installs directly to the windowsill, these machines rely on an outside venting source to operate efficiently. The easiest thing to use is your window!

To install these devices, you have to fit them into the window and use the included gear to create a seemingly tight fit. For window air conditioning units, that’s usually an accordion-style frame that stretches to cover the opening on both sides of the open window. With portable units, it’s a much smaller hose fitting. However, it still uses an adjustable barrier to close off the window opening.

The trouble with this installation method is that no design fits every window perfectly! The adjustable accessories do a lot to create a fit that seems snug, but there’s a good chance that small cracks and openings exist around the unit itself and the covering accessories.

Those are how bugs end up coming in through your air conditioner! It’s not through the intricate cooling equipment inside. Some bugs can squeeze through there, but a vast majority will use those cracks to find a path inside.

What Causes Them To Do This?

There are a few reasons why bugs might find themselves so inclined to crawl through your air conditioner.

The two most obvious draws are food and shelter. Insects are constantly on the lookout for a place that sustains life. They want to be safe and have easy access to food.

If you eat in your room, the aroma is likely enticing them. Air conditioners work by recirculating air. Those tiny scent particles go along for the ride, creating a small scent trail that will eventually get out through the cracks of the AC seal.

That draws in insects that want to investigate, which ends up creating an endless cycle of attraction! Small bugs hang out around your air conditioner, which brings in the bigger predator insects that want to feast.

Bugs can also end up inside your air conditioner because of the promise of shelter. Let’s face it, your home is much safer for bugs than the unknowns outside. Bugs know that as well!

Many can also feel the distinct temperature change going on. Whether it’s hotter or colder, the inside air seeps outside and gives bugs a glimpse of the haven you created. Contrary to popular belief, keeping your home cool doesn’t always keep pests out.

Quick Tip: Some bugs like the cooler temperatures! Having that tease from the cracks will only motivate the bugs to find a way inside.

Finally, there’s the issue of light. Several bugs are naturally drawn to light. That’s why your porch fixtures experience a swarm of insects every night.

Air conditioners do a pretty good job of blocking light, but those openings around the perimeter act like a beacon of illumination that’s just asking bugs to come in.

In most cases, it’s a combination of food, shelter, and light that draws insects in. Ultimately, your air-conditioned room offers the promise of comfort and safety, which only encourages the bugs to crawl on through.

How To Prevent Bugs From Coming In Through Your Air Conditioner

Tired of seeing bugs coming in through your air conditioner? Don’t ignore the problem! If one bug enters, it’s only a matter of time before more follow. Before you know it, you’ll have a growing infestation that continues to multiply.

Address the issue as soon as possible to avoid complications later on. Fortunately, there are many ways to prevent bugs from coming in through your air conditioner.

1. Secure The Seal With Duct Tape

The cheapest and quickest way to prevent bugs from coming in through your air conditioner is to use a bit of duct tape! As you probably know, duct tape has a reputation for being the ultimate quick-fix option.

Most people associate this heavy-duty adhesive tape with oddball projects and packing boxes. However, its original purpose was to help HVAC specialists construct ducts. If it’s strong enough to wrap full-sized ducts, it’s more than capable of keeping bugs out of your window air conditioning unit.

Use thick strips to seal up all cracks. When done right,you should notice a dramatic difference. Plus, it may improve the performance of the unit!

Quick Tip: It’s best to do this in the daytime when the sun is shining outside. Get down low and look for the light peaking through the cracks around the perimeter. Rip thick strips to seal them shut.

2. Close Cracks & Voids With Caulk

If you want a more permanent and tidy option, go with caulk. Caulk is an excellent tool for keeping bugs out of your air conditioning unit if you plan on keeping your unit in the same room for several years.

There are many different kinds of caulk out there. Your best bet is to go with an all-purpose caulk that’s made for basic sealing. Make sure it adheres to the material used around your window. For most homeowners, that will be wood.

Use a caulk gun to deposit the liquid around the perimeter of the AC unit and accessories. Pay close attention to small voids. Then, use your finger or a scraper to push the product into the crack and create a smooth finish.

For a more straightforward application, you can also use rope caulk. Use it to wrap the perimeter without all of the messy gunk.

Quick Tip: Most caulk products hold up well for several years. However, you can easily scrape it off if you ever decide to move the AC unit.

3. Install A Protective Screen

Here’s a great solution that will prevent bugs from coming in through your air conditioner or the surrounding gaps in the unit.

Screens are fantastic for keeping bugs out of your air conditioner. As you probably know, many homes in the South have windows that are equipped with built-in screens. You can use them to your advantage for some additional protection.

For exhaust ducts or units that sit flush against the window, screen coverings work well. Alternatively, you can use loose screen material or go all-out with a full protective cap over the window.

Whatever you choose, make sure that the screen is installed correctly. It won’t keep bugs out of your air conditioner if the screen also has gaps that they can wriggle their way through!

4. Add Additional Barriers

If all else fails, you can use other materials to create a physical barrier that blocks bugs directly.

This is a common tactic for those who own AC units with accordion-style flaps. Those accessories are notoriously flimsy, so it pays to use extra reinforcement.

You can use thick cardboard to cover the adjustable material. Use duct tape to cover every gap. Some homeowners have found success with fabric and blankets, too.

It’s not the prettiest solution, but it’s one that provides quick results.

Insects That Are More Likely To Come In Through Your Air Conditioner

A buzzing air conditioning system can attract a wide range of bugs. 

The most common to crawl through are flies, mosquitos, spiders, and roaches. Smaller species are more likely to find their way in. 

Mosquitos are the worst offenders on hot summer days. They can often feel the temperature difference and will try to enter if the conditions are right. They prefer temperatures around 80 degrees, which may be cooler than scorching weather outside.

Flies tend to come in because they detect the CO2 you breathe out. If you spend a lot of time in the air-conditioned room, CO2 can leak out and attract them.

As for spiders and roaches, the main attractors are food and shelter. Spiders love to hang out around AC units because of all the smaller bugs they bring in. It’s not uncommon to see spiders weaving webs to catch all the flies that want to enter.

While mosquitos, flies, cockroaches, and spiders are the worst offenders, what bug successfully makes its way through your air conditioner depends entirely on the size of the voids.

If you have massive holes around the AC unit, don’t be surprised if you find giant American roaches and flying pests around your room. Believe it or not, even bats can take advantage of your air conditioner. They hover around the unit until they can crawl through the void and squeeze their way into your house!

Many devices come with built-in filters. Make sure to use them, as they can make things a lot more difficult for pests.

Will Bugs Live In Your Air Conditioner?

Seeing bugs crawl through the air conditioning vents to get into your home is bad enough. But to have them actively living there? That can be a nightmare!

You might be surprised to discover that many bugs will gladly live inside air conditioners, but it’s not hard to see why. Many systems have relatively empty interiors that pests can utilize. Right off the bat, the “shelter” issue is resolved.

On top of that, air conditioners provide easy access to food and water.

Predator bugs have the most to gain. They can live inside the unit and wait for the smaller prey. Some AC units are strong enough to suck the small flies right in, turning a once complicated task into a glorified food delivery system!

As for water, many AC units leak water. The cooling system’s constant exposure to hot and humid air leads to intense condensation. While most of it drips out the back, some accumulate inside to give nearby bugs plenty of hydration.

Bugs can end up living in your air conditioner for a long time. A vast majority will pass through, but those that want to stick around have all the means they need to survive.

To avoid that nightmare of a problem, you’ll need to use some of our tips to treat your system and keep bugs out of your air conditioner from the get-go.

Closing Thoughts

Even though bugs can crawl through air conditioners into your home, this isn’t something you should lose a lot of sleep over. You won’t have anything to worry about as long as you take smart preventative measures to keep them out.

If you have any questions about the methods we listed above (or some DIY tricks you’ve discovered), we’d love to hear from you. Just drop us a line via our contact form!

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