HVAC System Cleaning: 13 Things (2024) You Must Know

Worried about the air quality in your home?

Thinking about HVAC system cleaning?

You’re not the only one.

The Environmental Protection Agency (EPA) estimates that Americans spend about 90 percent of their time indoors.

And because indoors often features higher levels of pollutants than outdoors, you can be at higher risk for problems if you’re not monitoring your air quality.

This is why many homeowners consider an HVAC system cleaning so they can feel good about the air that’s being cycled in and out of their homes.

But before you put down the money, you do a bit of due diligence.

This service may not actually be needed.

Read on to learn more!

1. What is an HVAC system?

An HVAC system is a ventilation, heating, and cooling system.

It’s a combination system that heats a space in the winter and cools it in the summer.

An HVAC system also includes other systems such as heat pumps and air purifiers.

If you want everything in your home to work together, this is an incredibly convenient way to do it.

You’ll be able to control all systems with a single thermostat, even a smart thermostat if you’d like.

These units control humidity levels and improve air quality by capturing bacteria, spores, and virus-sized particles.

However, over time, these units do build up dust.

If you don’t clean them, then they won’t be able to perform their intended function.

That said, you don’t need to keep your air duct spotless, and below, we’ll talk about when it’s really necessary to clean your ducts because — spoiler alert — it isn’t always when an HVAC system cleaning company tells you it’s necessary.

2. What are the signs that your HVAC system needs to be cleaned?

It’s can be tricky to know whether to invest in an HVAC system cleaning.

Is a company just trying to sell a service to you, or is this really needed?

Since the EPA doesn’t recommend HVAC cleaning annually, you’ll want to look for signs that your system needs to be cleaned:

bulletThe external vents are covered in mold and mildew

bulletThe filter is covered in dust and dirt build-up

bulletThe system is blowing hot air when it should cold

bulletThe unit is rattling, wheezing, or huffing

bulletThe HVAC has a strong smell coming from it

3. What should you know about HVAC system cleaning?

If you’ve never lived in a space that requires HVAC system cleaning, you may not know anything about these systems or why they require you to maintain them.

Here are the basics about what you should know.

First, ducts get dusty.

This is normal and expected.

As they perform their function, they will begin to accumulate dust.

Yet, cleaning of this dust isn’t necessarily performed regularly.

Rather, “as-needed” cleaning is a better approach.

4. Why isn’t routine HVAC duct cleaning required?

It may seem a little counter-intuitive that HVAC system cleaning isn’t a regular event (like your dryer duct cleaning).

However, the EPA doesn’t recommend frequently cleaning the dust out of your HVAC system because it doesn’t necessarily provide better value for the system.

It appears that your HVAC performs about the same whether there’s dust in there or there isn’t.

So, no external/objective organization recommends regular cleaning for your HVAC system.

That said, you may get some companies (like the HVAC system cleaning companies) who will tell you it’s beneficial because it’s profitable for them, so keep that in mind.

They may even send you photos with “before” or “after” ducts, trying to scare you with images of what your ducts could look like after so many years without cleaning.

Yet, it’s unlikely that your ducts are that bad – and if they are, you should be cleaning the entire HVAC system (not just the ducts).

The EPA recommends cleaning your air ducts if and when you notice the following.

bulletYour ducts are filthy (not just dusty)

bulletYour ducts are infested with mice or other vermin

bulletYou see evidence of significant visible mold growth in the ducts or on the mechanical components of the HVAC system that comes in contact with air

5. Is air duct sanitizing worth it?

You may read a lot of articles on the internet pointing to air duct cleaning and sanitizing.

However, beware that duct cleaning and sanitizing have never been shown to prevent health problems.

Just because dust is present in your ducts doesn’t mean it’s doing harm to you.

The studies that have been conducted have shown that the dirt and dust in air ducts will adhere to the surfaces inside the ducts.

However, they don’t necessarily enter the living space, which means they often do not impact humans living there.

Unless you’re seeing mold, insects/rodents, or excessive filth or dirt coming from your vents, then you’re probably fine to leave them as they are.

6. How often should you clean your HVAC system?

So, if routine annual cleaning isn’t recommended, approximately how often should you be maintaining it with proper cleaning?

According to one company, the National Air Duct Cleaners Association (NADCA) recommends cleaning this system every 3 to 5 years.

However, this recommendation is very much household dependent.

If factors inside your household decrease air quality, then you may need to move up this timeline.

Factors that would decrease air quality include:

bulletHaving smokers present in the household

bulletHaving pets that shed hair frequently

bulletHaving people with sensitive allergies

7. How is HVAC duct cleaning performed?

HVAC duct cleaning is performed by certified technicians who use specialized tools to agitate and dislodge dirt.

Once all the dirt is loosened, the technician will vacuum it out of the duct.

In some cases, your technician may cut your air ducts so they can properly reach areas that would otherwise be unreachable.

This is something that only professionals should do.

After the cleaning is complete, the ducts will need to be properly resealed.

The final step of duct cleaning is a powerful vacuum system removing air duct contamination.

Air duct contamination is when the duct is filled with mold, bacteria, pollen, dust mites, chemical residue, and other household pollutants.

If your HVAC system doesn’t work properly, has ineffective air filters, has moisture buildup, or has improperly installed ductwork, then it’s at risk for air duct contamination.

This is yet another step that should be done properly because it can cause more harm than good if it’s not executed correctly.

8. What is the difference between HVAC system cleaning and duct cleaning?

Duct cleaning and HVAC system cleaning are not the same processes.

If you’re going to clean your ducts, you really you need to clean the entire HVAC system.

The NADCA recommends all the following for HVAC system cleaning:

bulletDuct cleaning

bulletCleaning and replacing the air filter

bulletCleaning grilles and diffusers

bulletChecking drain pans and drain lines for proper drainage

bulletChecking the heat exchanger, cooling coils, grills, furnace air plenum, blower motor, etc.

9. How do you minimize risk if you’re having your HVAC system cleaned?

The best way to minimize risk is by hiring a qualified contractor.

Do your due diligence and research who you’re hiring to do this job.

It may seem worth it to save some extra money and go with the company that sends you a coupon in the mail.

However, these companies can cause damage or scam you. So, watch out!

You want to hire someone who is trained and certified by the NADCA.

They understand what needs to be done and will do it safely.

10. If I’m hiring an HVAC company, what should be included in the duct cleaning service?

If you didn’t even know this type of service should be performed on your HVAC system, you may not know what to ask the company.

At a minimum, the NADCA advises that you ensure that the following items are covered.

bulletHVAC Ducts

When you think of an HVAC system cleaning, you probably primarily think of your HVAC ducts.

This is what most companies will target when they’re trying to get your business.

This is a core part of the cleaning, but it isn’t the entirety of the process.

To clean your HVAC ducts, you’ll need to address the main supply duct, branch distribution ducts, and return air ducts.

You’ll also need to seal all installation access panels in ducts per NADCA standards.

bulletGrills and Diffusers

The grills cover the air vents, and the diffusers ventilate conditioned air.

These pieces must be removed and visibly cleaned during the process.

bulletFurnace Plenums

The furnace plenum is a box that connects to the HVAC system and brings in the air to distribute it (as well as remove it).

Both the supply air plenum and the return air plenum must be cleaned.

bulletFurnace Components

There are a variety of components in the furnace that must be addressed to ensure it continues to work correctly.

These components include the furnace heat exchanger; blower motor as well as its housing and assembly; humidifier media and drain pan; and evaporator coil, drain, and pan drain.

All these items should be checked, cleaned, and dried properly.

bulletFurnace Air Filter

You’ll also need to replace your furnace air filter or wash the permanent media air filter depending on what you have.

11. How much does it cost for HVAC system cleaning?

It’s around $500 to $1,000 for a professional HVAC cleaning service.

This is a significant sum, and it could vary depending on a variety of factors including the location of the home, the size of the home, and the scope of what is cleaned.

However, it’s worth paying more for a professional technician to do it right than risk being scammed or having your system ruined.

12. How long does cleaning take?

If you have two technicians come to clean your HVAC system in its entirety, then it’ll usually take around 3 to 5 hours for both the ducts and the system itself.

13. What are the pros and cons of HVAC system cleaning?


When done properly, here are the pros of performing HVAC system cleaning.

  1. Increases the efficiency and lifespan of your HVAC
  2. Eliminates the risk of dangerous diseases
  3. Creates a hygienic environment without allergens
  4. Gets rid of unpleasant odors
  5. Prevents you from spending unnecessary money every year


An HVAC system cleaning can open up a whole new can of worms.

Once a professional technician sees what’s happening in your ducts, they may suggest repair or replacement of parts.

This can get expensive.

In some ways, it is inevitable.

You can’t put off repairing something that is necessary, but it’s never fun to hear about an expensive repair or replacement in your home.

Beware of HVAC System Cleaning Scams!

As with many services nowadays, there are dust-cleaning scams that are becoming issues for homeowners.

Not only are there companies that are selling cheap services, but there are also companies that are not properly performing the dust cleaning.

If you encounter a cleaner that advertises a $50 “whole house special,” then you should be on your guard.

This can be a scam.

One tell-tale sign that it may be a con is featuring a certification by the EPA.

The EPA doesn’t provide or recommend duct cleaning.

Companies will sometimes try to attempt to use a government agency with authority to gain people’s trust. Be wary of this!

Another common tactic is when companies send “coupons” for a service at a cheap price.

The starting price may be $50, but they’ll attempt to sell you add-on services or upgrades that end up making it much more expensive than you would’ve expected.

The low price may draw you in, but these companies are questionable.

It’s much better to hire a qualified service technician armed with proper equipment to perform HVAC system cleaning.

Final Thoughts

HVAC system cleaning is necessary only when it’s necessary.

Helpful, right?

This type of cleaning isn’t the type that you should add to an annual spring-cleaning list, and you shouldn’t let any company try to convince and sell you on that.

Rather, you should conduct periodic checks on your HVAC system and if your HVAC is filthy — so dirty you’re worried about its proper functioning — then you should hire a professionally certified technician with the proper equipment to help clean the entire system (not just the ducts).

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Erika Gokce Capital

Disclaimer: we are not lawyers, accountants or financial advisors and the information in this article is for informational purposes only. This article is based on our own research and experience and we do our best to keep it accurate and up-to-date, but it may contain errors. Please be sure to consult a legal or financial professional before making any investment decisions.


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