Can Mice Get in Through Your Air Conditioner?

Air conditioning is a basic household need for most homeowners and especially during the warmer months of the year. Having a nice cool home is a pleasant respite the harsh temperatures and humidity outside. Your home AC is built to last, but just like any other household appliance is prone to fail, and it’s worse when it fails due to rodent damage when mice come through the air vents. The insulation in air conditioning units often attracts mice, since its warm and suitable for nesting. Mice can get in through your entry-points such as air conditioner via air vents, pipe entries, block access panels and cable entries. The first sign of mice living in your air conditioner is mice droppings around outdoor air conditioning units, and occasionally you will spot dead mice which look like they have been electrocuted. There are many pests that will invade your air conditioning unit, but mice and rats are the most worrisome. Mice will gnaw on wiring or build nests that can put a strain on the unit. Even more disturbing is that mice can enter your home through an air conditioner. Fortunately, you can avoid problems by mouse proofing your home and AC units by calling your mice exterminator Toronto.

How Mice Get In

House Mouse (Mus domesticus) in nature among fallen autumn leaves.
House Mouse (Mus domesticus) in nature among fallen autumn leaves.

First, you need to understand how they get in. Mice will slip into the tiniest of spaces. An air conditioner is a perfect place for a mouse because the air ducts contain materials they can use to build suitable nests. Unfortunately, mice are notorious for chewing, which means they can cause significant damages to electrical wiring and refrigerant lines found inside the unit.

The damages created by a mouse may prove hazardous for you and expensive to repair. Therefore, finding ways to keep mice out of your AC unit, and therefore out of your home, is of the utmost importance. Mice will find gaps leading into your home or into your air ducts to gain entry from the AC unit, so it is best to stop them in their tracks.

Pest Proofing

weep vents - stop mice before they get in
weep vents – stop mice before they get in

Pest proofing is something you should do no matter if you have a pest problem or not. Because there are many other critters that would like to make your AC a home, you should make pest proofing a part of regular maintenance.

You can pest-proof in various ways. The following are just some of the ways you can prevent mice and other pests from entering your AC and gaining access to your home:

  • Install covers: You can find special coverings and mesh screens specifically made for AC units that cover air vents and flues. Make sure you cover your vents and flue pipes to prevent mice from getting into your home. In case you spot a crack or duct, repair promptly since mice can get in through air vent cracks and ducts.
  • Seal entry points: The air ducts of your AC serve as the perfect way for a mouse to get into your home. Make sure you seal any cracks or gaps in the ducts so mice cannot get in and repair damage ducts immediately. Mice can fit through a hole that is half the size of a nickel, ensure your air ducts are properly sealed to discourage mice from moving in.
  • Prevent moisture: Moisture buildup around the AC unit is one reason pests, such as mice, will invade the unit. The moisture provides them with something to drink, and hydration is necessary for mice. Prevent moisture by redirecting puddles from rain or condensation that form around the unit.
  • Guard your condenser. Most times, rodents such as mice move into your AC unit through its air vents. Clear all vegetation around the unit including stacked up material near the AC since they could attract mice.

Repeat this routine occasionally and through the seasons. You will need to be extra careful during seasons when your air conditioning system is not in use since they are most likely to attack them. If you are unsure of how to go about this, contact your local pest control service to help you out. Dealing with mice in your AC unit is a big deal. Dealing with them using your AC to enter your home is even bigger. Fortunately, preventing them from entering your AC in your home is simple. If you need additional help getting mice out of your air conditioning unit, contact a pest control professional for assistance.

Can Mice Travel Through Air Vents and Build Nests Inside Your Home?

mice can get inside your home via AC unit
mice can get inside your home via AC unit

Mice will be drawn to your home due to three simple reasons. They are looking for a safe, warm place stocked with food. When mice invade your home, they will normally use the darkest corridors they can find, and more often it’s usually your air vents. They will use your air vents to run around in search of food. Mice have the capability of climbing and slipping through holes as tiny as a coin size. Therefore there is no stopping them if they go undetected.

Your air conditioning system is an integral part of your home, and it’s more useful to the family during the summer. Having your air conditioning run fine is always a nice thing especially when it is scorching outside. While most AC’sare built with durability in mind, like any other piece of equipment, itis prone to failure. It’s very annoying to find out that your AC system is damaged due to an infestation. Well, when mice use your air vents as passages while they forage for food, they could easily end up inside your HVAC equipment where they are known to cause damage to the equipment by chewing up the wires and cabling.

The insulation that is used in your HVAC system is what attracts mice in the first place. It’s warm and offers a safe place for nesting. When mice get into your AC system through the vents, they block the access panels with debris. One of the first signs that you might have mice in your HVAC system is when you spot mice droppings. They are usually crunchy and resemble a rice grain. You can easily spot them around your outdoor air conditioning systems.

How To Prevent Mice From Chewing AC Wires

electrical AC wiring harness chewed on by mice causing damage
electrical AC wiring harness chewed on by mice causing damage

There are some measures you can take yourself to ensure that pests do not go inside the AC and chew wiring. You might want to install mesh wiring to protect your air covers and flues. For this you need to buy specialized mesh covers for that purpose.  Sealing air ducts will make sure that rodents will not exploit the cracks, crevices, or holes wide enough to pass through and to access the AC. Covering air vents and grilles will prevent other animals such as birds make a nest inside the unit. Reducing moisture around the AC unit will reduce the probability that rats and mice will have access to a water source. Lastly, you may want to contact professional mice control experts for tips and recommendations.

What Should I Do

The best line of action would be to implement pest proofing. This is something that matters whether you have a pest problem or not. Since there are several other critters that could get into your home through your air vents, it is important that this exercise be part of regular maintenance.

How to remove mice from air vents

Your air vents are the likely areas that mice will use as they look for food and a safe place to sleep. While mice often die inside these ducts, they can send a rank odour throughout your living areas. In case you notice you have mice in your air vents do the following.

  • Switch off your AC system allowing the grates to get to room temperature. Remove the grates that are used to cover your heat vents.
  • Bait a snap trap with food that mice love such as chocolates, peanut butter or raisings
  • Place these traps in each air vent.
  • Check the traps regularly each morning using a flashlight. If any mice have been trapped, remove them. Use rubber gloves and dispose of the mice in a Ziplock bag.

To prevent this type of infestation through your air vents, seal off any small holes that could give entry into your air vents. Also perform a thorough inspection of your house for silvers between ducts, wall or your roof. Ensure that they are covered with mesh to prevent the mice from slipping through.

In case you notice any rodent activity in your air vents, the best line of action would be to call an exterminator. They are more experienced in getting rid of rodents in difficult to reach areas in your home. They will also perform this task with minimal effort and damage to your home.

Mice in Window Air Conditioner

Window air conditioners are nifty things and useful when you need extra cool air for good circulation, but they can also harvest problems for mice wanting to find a way to get in your home. If you are not really sure if the intruder is alive or not, you will have to take it apart after it does not show itself. Window air conditioners are easy to take apart. You can lure the mouse out with some bait. Non-lethal or lethal is all up to you depending on the hat you would like to see in the end. It is quite common for a mouse to slip through vents since it only takes the size of roughly a coin in diameter to slip through without any problem. What most people tend to ignore or are not aware of is how flexible mouse limbs are.

Dead Mouse in Air Conditioner

It is inevitable that you will end up with a dead mouse in your air conditioner. There may be several factors that can be related to this, but this will not help the main issue. The first thing to determine is how deep you think the mouse went. In any case, you need to disassemble the air conditioner until you have clear access to the mouse itself. Make sure you wear all the protective gear as indirect exposure or any blood splattering can result in the transmission of disease which mice have 35 of. You need plastic bags, gloves, and a mask. You want to be careful and gentle with the mouse as possible as you do not know in what state you will see it. You can remove the mouse with the hand and dispose of the gloves right after. As an extra measure of precaution, make sure to wash your hands for at least twenty seconds with soap. Once you have removed the mouse would want to have it bagged and thrown in the trash. Make sure the bag is sealed properly.

How To Keep Mice Out of Air Conditioner Condenser

Mice, but also a host of other insects and rodents can do damage to your air conditioner condenser. When they find their way in they can chew through wiring and compromise the functionality of the air conditioner condenser which can eventually lead to a fuse. Mice, in particular, are drawn to these spaces as it provides the warmth and safety mice are looking for as colder month approaches. Also regular upkeep around the area where your air conditioner condenser is required to avoid other types of insects going into the condenser. Some water and soap should suffice to clean out the feces and excess pieces of plants and leaves that have gotten into the system over time.  Your air conditioner condenser uses flues pipes to dispel by-products from the furnace. These also help to prevent carbon monoxide poisoning. It  is strongly recommended to install vent covers on all exterior flues, exhausts, and intakes. It will prevent pests from blocking and building nests in the system and keep components safe from tampering.

Can Mice Climb Through Air Vents?

Yes, very easily. Mice can climb and squeeze through very tight holes and gaps. Most people underestimate the flexibility that mice have. They can find their way through air vents, cracks, and gaps. Mice can easily infest air vents and can scatter feces, urine, and compromise the functionality and components easily. Mice are more acrobatic than we like to think, they can easily climb elevated surfaces which may explain why mice can easily find themselves in houses. Mice only need the diameter of a quarter to squeeze through a hole, so keeping that in mind, an air vent would be very easy. Their teeth are quite strong which can aid them in chewing through the plastic vent covers.

Mouse Nest In Air Conditioner

Mouse nest in condenser control panel. Upon removal, the wiring is almost always damaged by chewing and the corrosive nature of mouse urine
Mouse nest in the condenser control panel. Upon removal, the wiring is almost always damaged by chewing and the corrosive nature of mouse urine (image by Compass Heating and Air Conditioning Inc.)

Mice are drawn to the warmth and the safety that the air conditioner can provide. Especially the HVAC unit or the air conditioner system. Mice can make their way through virtually any opening that they please and can start building a nest from shredded paper, leaves, and anything that gives them good insolation from the outside elements. It does not only stop at making themselves home in your HVAC or air conditioner unit, but can extend very well, if not always to damaging components, wiring, and the whole interior structure through the scattering of urine and fecal material. There are some clues that can help you detect a mouse nest.

  • If you smell a somewhat earthy smell and a mix of urine. That can indicate that something is inhabiting the air conditioner.
  • Seeing the mouse nest itself. You might see the mouse nest inside. The way you can find out whether you are seeing a mouse nest is seeing if you see a ball-shaped structure. Usually, the nest is comprised of a bunch of different materials like paper, leaves, cardboard, and other types of man-made material.

Can Mice Fit Through Vents

Yes and with relative ease, they can fit through gaps, crevices, and wholes as wide as a single quarter. Mice have very flexible limbs which allows them to take full advantage of their agility to enter a place. Mice often find themselves in new places because of the way they exploit entry-points. This makes it hard for laymen to efficiently combat a mice infestation because their eyes are not as trained enough to spot a gap susceptible to rodent intrusions in general. An area with a high wildlife presence may expect more mouse infestations because of how prays always have their eyes set on the humble mouse. If you notice any hole or gap, you need to have it sealed immediately by a professional that offers durable, non-destructible, and lock-term solutions that will prevent a second infestation from occurring.

How Can I Stop Mice from Getting Through AC Air Vents?

If you can fit a ball pen through a hole, a mouse can fit in. Mice are determined little critters, making it a challenge to prevent this type of damage. In case you notice signs of mice in your air conditioner, it’s important that you contact a pest control professional. Mice in your air conditioning system might mean you have a bigger rodent problem, and chances are, they have moved in through your AC’s air vent since they have grown in number with limited places to nest.

A pest control service will not only be able to get rid of the mice in your AC, but they will carry out an inspection to determine how and why the mice got in through your AC’s air vents. With this information, they will be in a better position to prevent future invasion into your AC unit. The Exterminators Inc. offers commercial and residential pest control services in Toronto as well as mouse control products for DIY enthusiasts. Call us at 647-496-2211 for a consultation.

Article Updated:  October 20, 2020

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