Air duct cleaning is done by heating, ventilation and air conditioning (HVAC) professionals. The pros use industrial-strength, truck-mounted vacuums and powerful brushes and hoses to clean inside the metal ducts that make up your forced air heating and cooling system. The Environmental Protection Agency recommends duct cleaning if there is “substantial visible mold growth inside hard surface ducts, ducts that are infested with vermin such as rodents or insects, or ducts that are clogged with excessive amounts of dust and debris and/or particles are actually released into the home from your supply registers.”

You should also have air ducts cleaned after recent water contamination or water damage to prevent mold; after renovations or remodeling to ensure debris and dust didn’t settle in the vents and ducts; if you are having problems with allergies or asthma; or when you are moving into a newly purchased home, especially if the previous owners smoked or had pets. The National Air Duct Cleaners Association (NADCA) recommends getting your air ducts cleaned every three to five years, or every two to three years in regions where homeowners use their air conditioning and heater for many months of the year, while the EPA suggests homeowners have duct cleaning done as needed.

How often you should clean your air ducts depends on your situation. If you or someone in the home has asthma or is acutely allergic to certain airborne materials or pollen, regular duct cleaning may be helpful. The Environmental Protection Agency doesn’t have an official position on the necessity of air duct cleaning unless the ducts have been contaminated by rodents, insects or mold, or you are aware of particles blowing out through the vents. The EPA recommends you have your air ducts cleaned on an as-needed basis. The National Air Duct Cleaners Association (NADCA) suggests having air ducts cleaned every three to five years.

Be cautious with companies that offer “whole house air duct cleaning,” urges the NADCA. The company may be using unscrupulous tactics to upsell you once they get started. Before any work begins, always clarify in writing what the job entails and what the cost will be. To protect yourself against fraud, read customer reviews and verify that your HVAC cleaning service has applicable licenses and certifications.

If your air ducts have been damaged, you’ll need to replace them. The national average air duct replacement cost is $150-$280, which may not include materials. Factors such as duct material, labor, location of ducts and linear feet of ductwork will all affect your final costs. Labor costs will vary based on how accessible the ducts are and what material your ducts are made of. The least expensive duct material is a flexible, non-metallic ducting that costs approximately $1-$2 per linear foot. Flexible aluminum is generally more expensive and stronger than non-metallic ducting. Stainless steel ducting is the strongest, the least flexible (meaning installing it typically has higher labor rates), and usually the most expensive. An average price for air duct replacement could range between $35 and $55 per linear foot, including basic materials and labor. A typical single-family home has 6-10 duct runs; replacing or installing one duct run could average $150-$250 for labor.

If you’re concerned about dust, allergens or mold, it may be time to have your air ducts cleaned. The national average cost for air duct cleaning ranges from $190 to $250. Air duct cleaning costs will vary based on a number of factors such as your location in the country, the age and condition of your air ducts, the number of linear feet to be cleaned, and any repairs your ducts may need. HVAC cleaning companies should clearly outline what is included in their services and at what rate, so always make sure you understand and have a written agreement before work begins. Here are some examples of average air duct cleaning costs:

• Tiered pricing for different levels of service:
• Standard cleaning: $100, which may include truck-mounted industrial vacuums, high-pressure air wands and air snakes to clean all supply and return vents, branch lines, and main trunk lines.
• Advanced cleaning: $200, which may include standard cleaning services, plus rotobrush or viper clean sweep in the main trunk lines.
• Ultimate cleaning: $400, which may include advanced cleaning, plus insertion of a viper microline into all vents to force debris down the branch lines and into the main trunk lines, to be handled by the viper clean sweep. Typically, all ductwork surface is contacted, before-and-after photos are provided, and the furnace is cleaned.
• A flat rate for unlimited vents: $289.
• Additional fees for larger houses: $20 for each additional 500 square feet over 2,500.

The amount of time air duct cleaning takes can depend on how extensive your duct system is, how old your air ducts are, and whether they have ever been cleaned. On average, expect a standard size home (between 2,000 and 3,000 square feet) to take 2-5 hours for one to two technicians to clean. Here are the proper protocol and equipment you should expect from a professional duct cleaning service, as recommended by the Environmental Protection Agency:

• All doors and access ports opened to ensure the entire duct system is inspected and cleaned.
• Thorough system inspection prior to cleaning to identify possible asbestos-containing materials. If asbestos is present, specially trained and equipped contractors must do the removal.
• Use of approved vacuum equipment that exhausts particles outside of your house. If the vacuum exhausts inside your home, it must be HEPA equipment.
• Furnishings and carpet covered and protected.
• Soft-bristled brushes only on fiberglass duct board and sheet metal ducts internally lined with fiberglass.
• Ductwork properly protected.
• Adherence to guidelines and practices set down by the National Air Duct Cleaners Association.