Frequently Asked Questions

Here are a few of the questions that come up most frequently. If your question isn’t addressed here, please don’t hesitate to call us at 1-800-200-8872.

Are there any health benefits that come from HVAC system cleaning?

Yes. Heating, ventilation, and air conditioning (HVAC) systems have been shown to act as a collection source for a variety of contaminants such as mold, fungi, bacteria, and very small particles of dust, all of which have the potential to affect health. The removal of these contaminants from your home’s HVAC system is one component in an overall plan to improve indoor air quality.

Will an HVAC system cleaning reduce our home energy bills?

Research by the U.S. Environmental Protection Agency (EPA) has demonstrated that HVAC system cleaning may allow systems to run more efficiently by removing debris from sensitive mechanical components. Clean, efficient HVAC systems are less likely to break down, have a longer life span, and generally operate more effectively than dirty systems.

How should a residential HVAC system be cleaned?

The most effective way to clean air ducts and ventilation systems is to employ Source Removal methods of cleaning. This requires a contractor to place the system under negative pressure, through the use of a powerful, specialized vacuum. While the vacuum draws air through the system, devices are inserted into the ducts to dislodge any debris that might be stuck to interior surfaces. The debris can then travel down the ducts to the vacuum, which removes it from the system and the home.

What kind of equipment is best for cleaning – truck mounted vacuums or portable vacuums?

NADCA does not endorse one kind of equipment over another. There are two main types of vacuum collection devices: (1) those mounted on trucks and trailers, and (2) portable units. Truck/trailer mounted equipment is generally more powerful than portable equipment. However, portable equipment can often be brought directly into a facility, allowing the vacuum source to be located closer to the ductwork.

Both types of equipment clean to NADCA standards. All vacuum units should be attached to a collection device for safe containment prior to disposal. Any vacuum collection device which exhausts indoors must be HEPA (high efficiency particulate arrestance) filtered. A vacuum collection device alone will not clean a HVAC system; rather, the use of methods and tools designed to agitate debris adhered to the surfaces within the system (for example: brushes, air whips, and “skipper balls”), in conjunction with the use of the vacuum collection device, is required to clean HVAC systems.

How often should residential HVAC systems be cleaned?

Frequency of cleaning depends on several factors, not the least of which is the preference of the home owner. Some of the things that may lead a home owner to consider more frequent cleaning include:

  • Smokers in the household
  • Pets that shed high amounts of hair and dander
  • Water contamination or damage to the home or HVAC system
  • Residents with allergies or asthma who might benefit from a reduction in the amount of indoor air pollutants in the home’s HVAC system
  • After home renovations or remodeling
  • Prior to occupancy of a new home

What exactly does a professional HVAC cleaning job include?

A professional HVAC or air duct cleaning job includes the furnace, furnace blower, air conditioning coils, registers, returns, air ducts and sanitation. Cleaning only part of the system is not effective. For example, a dirty furnace blower will re-contaminate the air duct system after cleaning. That’s why it’s important to make sure the entire system is cleaned and to ensure that the price quote includes your entire HVAC system. Unfortunately some companies will advertise a very low price and then charge extra for the furnace, sanitizing and other line items. Be cautious. An advertised price of $99 could easily turn into a $600 bill.

What is the normal price range for the air duct cleaning service?

The Environmental Protection Agency (EPA) says that “duct cleaning services typically – but not always – range in cost from $450 to $1000 per heating and cooling system, depending on the services offered, the size of the system to be cleaned, system accessibility, climactic region, level of contamination, and type of duct material.”

Consumers should beware of air duct cleaning companies who make sweeping claims about the health benefits of duct cleaning – such claims are unsubstantiated. Consumers should also beware of “blow-and-go” air duct cleaning companies. These companies often charge a nominal fee and do a poor job of cleaning the heating and cooling system. Representatives often show up in their own cars as opposed to company vehicles with nothing more than a vacuum unit similar to a shopvac. These companies may also persuade the consumer into unneeded services with or without their permission. (If you have knowledge of a practicing “blow-and-go” air duct cleaner, please contact your local Better Business Bureau to report the company.)

What criteria should I use in selecting an HVAC system cleaner?

Interview as many local contractors as possible. Ask them to come to your home and perform a system inspection and give you a price quotation. To narrow down your pool of potential contractors, use the following pre-qualifications:

  • Make sure the company is a member in good standing of the National Air Duct Cleaners Association (NADCA).
  • Verify that the company is certified by NADCA to perform HVAC system cleaning.
  • Always check the license status at or call 1-800-321-2752.
  • See if the company has been in business long enough to have adequate experience.
  • Inquire whether the company is in good standing with your local Better Business Bureau.
  • Get proof that the company is properly licensed and adequately insured.
  • Make sure that the company is going to clean and visually inspect all of the air ducts and related system components.
  • Avoid advertisements for “$99 whole house specials” and other sales gimmicks.
  • Ask if the company has the right equipment to effectively perform cleaning, and if the company has done work in homes similar to yours. Get references from neighbors if possible.

Why should I choose a NADCA member to have my air ducts cleaned?

NADCA Members have signed a code of ethics stating they will do everything possible to protect the consumer and follow NADCA Standards for cleaning to the best of their ability. Air duct cleaning companies must meet stringent requirements to become a NADCA Member. Among those requirements, all NADCA Members must have certified Air System Cleaning Specialists (ASCS) on staff who have taken and passed the NADCA certification examination. Passing the exam demonstrates extensive knowledge in HVAC design and cleaning methodologies. ASCS’s are also required to further their industry education by attending seminars in order to maintain their NADCA certification status.

What are sanitizers, and why do they need to be used?

Sanitizers are anti-microbial chemicals applied to the interior surface of the air ducts, designed to control microbial contamination. Before any sanitizers are used, the system should be thoroughly cleaned. It is critical that any anti-microbial treatment used in your system be EPA registered for the intended use in HVAC systems. Ask to see the chemical’s Material Safety Data Sheet (MSDS). If you are still concerned, call the EPA at 1-800-438-4318. It should be noted that there are no EPA registered anti-microbial products for use on porous system surfaces – such as fiberglass surfaces.

How long should it take to clean a typical residential HVAC system?

There are a variety of factors that could affect the time needed to clean a residential HVAC system, including the type of home, accessibility to the ductwork, and the number of workers on the project. A typical three or four bedroom home will require 2 to 4 hours for cleaning.

How can we determine if the HVAC system cleaning was effective?

The best way to determine if the HVAC system cleaning was effective is to perform a visual inspection of the system before and after cleaning. If any dust or debris can be seen during the visual inspection, the system should not be considered cleaned. While you can perform your own visual inspection using a flash light and mirror, a professional cleaning contractor should be able to allow you better access to system components and perhaps the use of specialized inspection tools. In addition, following this post-cleaning check list can help to ensure a top quality job.