Rosie on the House: How often should ductwork be cleaned?

Answer: In a properly maintained HVAC system, duct cleaning probably isn’t necessary more than every seven to 10 years. What is important is changing the filter monthly. Generally, a one-inch paper pleated filter is safe for all systems.

Q: When should I have my ductwork professionally cleaned?

A: Temperature Control Inc., a Rosie-Certified Partner, explains that the ductwork is responsible for delivering conditioned air to the rooms of your home. If there’s any buildup of debris restricting airflow, the HVAC system needs to work that much harder and longer. Equipment wear and tear, the greater chance of malfunction, greatly reduced air quality, and higher utility bills are just some of the consequences.

The EPA suggests having the ducts cleaned under these conditions:

• There is substantial visible mold growth inside hard surface (e.g., sheet metal) ducts or on other components of your heating and cooling system.

• Ducts are infested with vermin, e.g. (rodents or insects).

• Ducts are clogged with excessive amounts of dust and debris and/or particles are actually released into the home from your supply registers.

Additionally, if you have recently remodeled, you may want to consider having your ducts cleaned or repaired. Dust and debris may have built up around your air vents.

Q: What is involved in ductwork cleaning?

A: Duct cleaning is only one component of a proper system cleaning. It is extremely important that the return air ducts and/or plenum (a box that connects to the HVAC system that brings in, distributes, and removes air) are thoroughly cleaned and checked for air leaks. By the way, I can’t remember ever inspecting an air conditioning system that didn’t have some leaking. Yours probably does, too. It is not unusual to find 20% leakage or more. We like to see leakage under 5%. If there are unrepaired leaks, a good cleaning is pointless.

The company doing the work should be using an 8-inch diameter vacuum hose and a duct scrubbing device. A semi-rigid air hose that uses approximately 200 psi pressure and a multi-directional pressure tip is a good scrubber. The high-pressure air dislodges the dirt from the inside walls of your ductwork and is vacuumed to a large vacuum unit that is usually mounted on a truck. Handheld units are not adequate and should only be used in areas of limited access.

After sealing and cleaning the return air components, the evaporative coils in your air handler must be thoroughly cleaned. Some disassembly of your air conditioning unit is usually required and should only be completed by a licensed air conditioning specialist. Make sure they use a non-toxic cleaner. Remember, whatever they use will be released into the air after they restart the system.

A knowledgeable technician will be able to tell if you are using the wrong air filter and will recommend the right one.

For most people, duct cleaning has no benefit unless it’s part of a thorough cleaning of your entire air conditioning system by a licensed technician. Without a good cleaning of the air handler cabinet and coils, duct cleaning alone won’t make your air conditioner work better or reduce the dust in your house.

Pro Solutions Air Conditioning & Heating LLC, a Rosie-Certified Partner explains, “Some duct cleaners like to clean the A-coil inside and other parts of the HVAC system, calling it part of the duct cleaning. While it is good to have these things cleaned when the ducts are being cleaned, the coils can only be cleaned by ROC-licensed contractors who are fully knowledgeable about the workings of the entire HVAC unit. This is for your protection, to prevent damage caused by someone who is not fully HVAC educated.”

Q: Is there anything I should be concerned about when having the ductwork cleaned?

A: Yes. Coming in at No. 6 in my “Top 10 Things Homeowner Do Wrong,” is air duct cleaning.

Homeowners waste money getting their air ducts cleaned — improperly.

For example, some discount duct cleaning companies tend to pull up to your home at 10 a.m. The “technicians” remove the air conditioning supply registers in your home (usually eight to 12) and use a brush-headed vacuum system to clean as much of the ducts as they can see and reach. Approximately two hours later, they have packed up, cleaned up, collected their fee, and are headed to the next of four or five similar jobs that day. Nothing has been done to improve your home’s indoor air quality and you have just wasted as much as $250. You could have purchased a shop vacuum and done the job yourself, though your ducts wouldn’t be any cleaner or dirtier. The upside is at least you’d have a good shop vac.

A thorough cleaning and sealing of your return air, evaporative coils, air handler cabinet and supply registers should take two technicians at least half a day on an average-size home with one air conditioning system. Hence, the cost is at least twice what you see advertised by the discount duct cleaning “specialists.”

Duct cleaning is a common scam. Just because it is dusty Arizona, it doesn’t mean that you need an annual duct cleaning. You don’t.

However, when the time comes and you do need them cleaned, it is important that you hire an ROC-licensed HVAC company. Take it a step further and hire a certified air conditioning specialist. One poorly done “cleaning” could cost you a new HVAC system.

Hiring the right people for the job, when you actually need it will allow you to breathe a bit easier.