Flicking on your HVAC system only to be met with foul odors, strange noises, or worse, a sudden breakdown is a scene you won’t want to face.

The culprit, in this case, is usually the critters nesting in your HVAC system that somehow find their way in. And if not timely dealt with, critters can cause:

  • Blocked airflow leads to inefficient heating or cooling.
  • Gnawed electrical wires may cause a system failure.
  • Droppings in air ducts carry harmful diseases.
  • And more. 

Of course, dealing with these issues can be stressful, time-consuming, and costly, not to mention the ick factor of having pests in your ducts. 

So what’s the way out? Keeping these critters out of your HVAC system by pest-proofing it and maintaining an environment that doesn’t support their growth. 

Now you might wonder how you can pest-proof your HVAC system. If so, we hear you. Today, we’re here with the best hacks related to AC maintenance services that won’t let critters creep into your home’s systems. 

If you want a critter-free home without calling for professional HVAC maintenance services every now and then, read on to learn some cool hacks! 

  • Routine HVAC Maintenance

Regular maintenance is your first line of defense against critters in your HVAC system. Paying attention to your HVAC’s condition will help you spot and address early signs of critter infestations, such as unusual noises, foul smells, or unexplained system performance issues.

It’s good to schedule a professional HVAC inspection at least once or twice a year. Experienced technicians will provide testing HVAC services to assess the situation, clean and fix the system, and identify potential pests at entry points. They’ll also advise on what signs to watch for in case of an infestation. 

And if there’s time between professional visits, you can do your routine checks. Look for signs of gnawing, nesting materials, or droppings. Also, keep the area around outdoor units clean and free from tall grasses, branches, or other debris. Debris accumulation near vents and ducts can attract pests as it provides cover as critters approach your HVAC system. 

It’s also important to replace HVAC filters regularly. A clogged filter reduces your system’s efficiency and can harbor pests. A fresh, clean filter is less inviting to critters and will help your system function at its best.

  • Seal Ductwork

Sealing your ductwork is another critical step in HVAC services if you wish to keep your HVAC system critter-free. Gaps, cracks, and loose connections in ductwork can serve as entry points for various pests, from insects to rodents. Once inside, these critters can move freely throughout your home and spread allergens that impact indoor air quality. 

When you’re ready to seal your ductwork as part of AC maintenance service, look for any signs of damage or disconnections. You must pay particular attention to sections of ductwork in crawl spaces, attics, or other areas susceptible to pest invasions. 

Seal any gaps or cracks using high-quality, heat-resistant tape like foil tape or a mastic sealant. Avoid using standard cloth-backed duct tape as it tends not to last long in the varying temperatures of HVAC ducts.

If your ducts are not easily accessible, or if you notice significant damage, consider hiring professional HVAC maintenance services. They have the tools and expertise to ensure a thorough job and can also insulate your ducts to improve energy efficiency.

  • Do Proper Insulation in the HVAC System

What many don’t know is that the warmth that HVAC systems provide shelter to critters, especially during colder seasons. As they seek out these warm environments, they can end up in your home, resulting in a stubborn infestation. 

If your HVAC system lacks adequate insulation, it can create easy access points for critters. Therefore, keep all parts of your system, including the ductwork, properly insulated. 

Insulating your HVAC system creates a barrier against critters and improves your home’s energy efficiency. Proper insulation reduces heat loss, ensuring your HVAC system operates optimally and saves energy costs. 

Adding insulation can be a DIY job if you have basic handyman skills, but hiring a professional for AC maintenance service is better for a comprehensive and safer approach. 

  • Use Vent Screens

Vent screens act as barriers to your HVAC system that prevent critters from accessing your ductwork and, ultimately, your home. 

High-quality, durable vent screens will deter critters and withstand their attempts to breach the barrier. Metal screens are usually a good choice because of their durability and resistance to gnawing by critters. 

You can attach a vent screen to all exterior vents, including those for the dryer, bathroom, and stove hoods. Also, don’t forget the vents for the HVAC system itself. Regularly inspect these screens for signs of damage or wear and replace them as necessary.

While vent screens can prevent critters from entering your ductwork, they do not always guarantee complete protection. Some smaller pests may still get through, so combine vent screens with other preventative measures like regular HVAC maintenance and sealing ductwork.

  • Proper Landscaping

The landscaping around your house can directly influence the likelihood of critters invading your HVAC system. Dense vegetation and heaps of debris close to your home serve as perfect hideouts for critters and provide a protected path leading straight to your HVAC units.

It’s smart to trim the garden shrubs and ensure they are at least a few feet away from your HVAC unit. This gap prevents critters from using the vegetation as a stepping stone to your HVAC system and lets proper airflow around the unit.

Since fallen leaves can provide excellent nesting material for critters, don’t let fallen leaves and debris accumulate around your HVAC system. Regularly clean the area and keep it clear of debris so there is no grass around the ducts. Also, you can use gravel or rocks as a base around your outdoor units as they are less attractive to pests and discourage digging.

Another way you can keep critters out of sight is by being mindful of bird feeders and pet food. You must keep them away from HVAC units, as they can attract pests and, consequently, bigger critters hunting for a meal.

  • Cover AC and Duct Pipes

Unprotected pipes can become an open invitation for critters seeking shelter or warmth. You can use a breathable cover during the months when the outdoor AC is not in use. The cover should be breathable to prevent moisture build-up since it can damage your unit and attract pests. Pipe covers protect the unit from the elements and, more importantly, deter critters from nesting inside.

And as we explained above, you can use duct screens for duct pipes, particularly the ventilation pipes that exit your home. However, it’s good to regularly inspect these covers to check for any signs of damage or holes that might allow critters to enter and replace them as necessary.

  • Use Pesticides

Pesticides target specific pests and inhibit their activities so they don’t inhabit your HVAC system. So when nothing like cleaning or maintaining the ducts helps, get a pesticide treatment done to uproot this problem. 

But before spraying pesticides, identify the type of critter you’re dealing with. Different pests respond to different pesticides, and what works for one may not work for another. You might need to conduct some detective work, searching for signs of specific pests in your HVAC system and around your home.

Once you’ve identified the pest, choose a safe, effective, and suitable pesticide for that particular critter. Always remember to follow the instructions on the label. Misuse of pesticides can harm you, your pets, and the environment.

If you’re uncomfortable handling pesticides, consider hiring a pest control professional. They have the experience and knowledge to apply pesticides safely and effectively.

  • Cover the HVAC System During Off-Season

HVAC systems, particularly outdoor units, can be a magnet for critters when they’re not in use. Covering your HVAC system during the off-season can prevent these unwelcome visitors from making a home in your system.

The duct covers you use should withstand the elements but also be breathable to prevent moisture build-up. As moisture in HVAC ducts can cause mold growth and attract more pests, you must be careful. 

Also, keep the cover securely fastened so that it doesn’t blow off in strong winds or provide an opening for critters. You can do regular checks to ensure the cover is in good condition throughout the off-season.

  • Install A Chimney Cap

A chimney can be an unexpected entry point for critters into your HVAC system. Many animals, like birds, squirrels, and raccoons, can see your chimney as an ideal nesting spot or as a route into your home. Therefore getting a chimney cap is a wise move that keeps debris and critters at bay. 

A chimney cap is constructed of durable materials like stainless steel or copper. It serves several functions – it keeps out rain, reduces downdrafts, and, most importantly for this context, prevents critters from entering your chimney and, consequently, your HVAC system.

And like other HVAC covers recommended above, you should prefer a chimney cap with a mesh screening. It will keep out smaller pests like insects and larger ones like squirrels or raccoons.

Also, fixing this cap up high in the chimney takes some effort, so it’s better to get HVAC maintenance services.

  • Professional Duct Cleaning

A clean duct system leaves little room for critters to settle in. Thorough duct cleaning removes the materials critters might use for nesting and makes the environment less hospitable. It also helps spot early signs of an infestation, such as droppings, tracks, or critters.

However, you should know that over-cleaning or improper cleaning can cause damage to your ductwork and possibly lead to more issues. As a general guideline, duct cleaning should be done every three to five years or as a professional recommends based on your specific circumstances.

  • Minimize Outdoor Lighting

Insects are attracted to light, and lights around your home can draw them closer to your HVAC units. The increased presence of insects can, in turn, lure larger critters like lizards, birds, or rodents, who see this as a convenient feeding spot. 

It’s wise to switch off unnecessary outdoor lights, especially those close to your HVAC units, to minimize the attraction of critters. When lighting is needed, opt for yellow bug lights or sodium vapor lights, which are less attractive to insects. Also, consider using motion sensor lights, which are only on when needed.

The goal isn’t to eliminate outdoor lighting but to manage it strategically. This way, you maintain the benefits of outdoor lighting while reducing its attractiveness to critters.

  • Use Pest-Repelling Plants

Planting pest-repelling plants around your home and near your HVAC units is a natural and aesthetically pleasing way to deter critters. Certain plants produce fragrances or compounds that pests find disagreeable, making them an excellent organic pest control strategy.

For example, marigolds and chrysanthemums repel insects, while lavender and rosemary can deter rabbits and deer. Lemongrass, a plant that contains citronella, is well-known for its mosquito-repelling properties. So you can opt for any of these plants to keep your home pest-free organically.

However, you should position these plants correctly, as planting them too close to your HVAC units can block airflow and provide a hiding spot for critters – the exact scenario you’re trying to avoid. It’s best to plant these plants at a safe distance where their pest-repelling properties can be effective without interfering with your HVAC system.

Final Words On Keeping Your Home Critter-Free

Besides being a nuisance, critters are also potential destroyers of your precious HVAC system. But the good thing is you implement many smart tricks to overcome this problem and keep your home free of these annoying creatures. 

Planting pest-repelling flora, duct cleaning, and professional pest control are steps to support your commitment to showing critters the way. 

While it might take a bit of work, the peace of mind you get from knowing that your HVAC system is critter-free is worth it. And when things seem hard to control on your own, get expert AC maintenance services so these bugs can’t mess with your mental peace. 


How often should I clean my HVAC ducts to keep critters away?

While this can vary depending on your circumstances, a general guideline is to have your ducts professionally cleaned every three to five years. Regular cleaning helps remove debris and nesting materials, making the ducts less attractive to critters.

Should I cover my outdoor HVAC units to keep critters out?

Yes, covering your outdoor units, particularly during the off-season, can help deter critters. However, covers should be breathable to prevent moisture build-up.

Can professional pest control services help with critters in my HVAC system?

Pest control professionals have the experience and tools to effectively handle critters in your HVAC system. They can also provide valuable advice on preventative measures tailored to your home and region.