FAQs

If the ducts in your home have never been cleaned, it may be good to have it done. Even in new homes, there is often construction debris in the ductwork and fine particles like drywall dust that can affect your furnace and its performance. You may want to check your return ductwork since the returns pull air back to the furnace and this ductwork is frequently the dirtiest. The returns are usually larger and easier to access by removing the grill for inspection with a flashlight and a mirror. Other reasons to consider duct cleaning include: fire and water restoration, infestation of rodents or insects, installation of a new system, dust from a remodel, pet hair, odors and allergies or asthma.

A large specialized vacuum is attached to the system and special tools are used to dislodge dirt and debris inside the ductwork and push it towards the vacuum. Agitation devices should be used inside the ductwork to ensure debris is loosened from the walls of the ductwork. Access holes should be sealed according to industry standards. The entire system should be cleaned from where air enters through the return grilles to where the supply air comes out at the registers, including the air side surfaces of the furnace. The most effective way to clean air ducts is to use source removal, push-pull methods of cleaning, as defined by NADCA ACR 2006 Standards.

After thorough cleaning, the duct system should stay clean for 3 to 7 years if properly maintained with a high efficiency air filter. The filter should be changed regularly and should not have bypass air (air going around the filter). Some factors that influence frequency are living near a road that is sanded in the winter, living near fields or construction zones and having smokers or child care in the home. It is certainly not annual maintenance, and the EPA recommends duct cleaning on “as needed” basis rather than periodic.

Equipment does not clean ductwork…people do. The techniques and procedures used to clean the ducts are far more important than the type of equipment used. NADCA requires that a large, centralized vacuum be used to keep the entire system under constant negative air pressure while agitation devices (e.g., brushes, whips and air washers) loosen dirt and debris. The loosened debris is drawn out of the system by the vacuum. Ductwork cannot be cleaned properly using a small vacuum that pulls debris up through the registers and/or returns. Be leery of vacuum equipment that looks like it can fit in the trunk of a car.

In humid climates it is not uncommon for mold, fungus or bacteria to be present in ductwork. If mold or other contamination is present, it is important to first establish the cause and remediate it, or the contamination will likely return. Colorado has very dry air and it is very rare to see mold growing inside ductwork.

Applying sanitizers is not part of a routine air duct cleaning. If someone advises it, then have him/her show you why it is necessary. All chemicals have a safety data sheet (SDS) that can be found online. It provides details about the chemical, precautions, and any risks associated with it. The sheet must specifically state that it is approved for use in ventilation ductwork.

Unfortunately, many companies use sanitizer as a selling point. They often make sweeping health claims, maintaining that they are capable of removing mold, mildew, bacterial growth, etc. When unapproved chemicals get warm inside ductwork, they can turn into other toxic inhalants.

Due to growing concern over the use of sanitizer in ventilation ductwork, the Environmental Protection Agency (EPA) conducted a study and found that sanitizing ducts can cause serious health concerns and do not approve of its application within HVAC systems. The EPA has not registered any sanitizers for use in ductwork.

Price depends on factors such as the location of the system, the number of supply and return ducts and how many systems. Beware of companies offering whole-house specials for one low price. Air duct cleaning is not a regulated industry, so it is very easy for people to get into business using substandard equipment and inexperienced laborers and/or subcontractors. They often schedule as many jobs in one day as possible. Another unfortunate practice is known as bait and switch. A customer schedules whole house duct cleaning for an unbelievably low price (such as $99) and ends up with a $700 bill once the work is complete. They charge for things normally included in the service that should have been discussed prior to scheduling. The service provider should take time to explain the process and discuss any fluctuations in price.

The best way to determine whether system cleaning is effective is through visual inspection before and after cleaning. While you can perform an inspection with a mirror and flash light, a professional cleaner should be able to allow you better access to system components. In addition, NADCA offers this post-cleaning checklist.

Yes! Complete system cleaning can increase efficiency. According to Bob Baker and Ross Montgomery, who study air quality and energy efficiency for the American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASRAE), research shows dirty coils and blowers in commercial buildings can cut efficiency by as much as 40 percent.

According to NADCA Air Duct Cleaning Specialists (ASCS) Tom Harrington & Grant Shallcross, believe a typical modern building’s air conditioning system accounts for up to 50% of its total energy consumption.

The longer the vent, the more often it should be cleaned. Experts recommend yearly.

Signs that the dryer vent may need to be cleaned:

• Clothes taking longer to dry.
• Clothes are unusually hot to the touch when removed from dryer.
• The exterior vent flap does not open when operating the dryer.

Please see our dedicated dryer vent cleaning page for more information.