Q: Will cleaning the inside of my heating and air conditioning ducts improve the air in my house and save energy?
A: Research showing energy savings from duct cleaning is lacking. There is some research suggesting that cleaning the blower and the coil, and cleaning or replacing the filter can improve efficiency and save energy, but duct cleaning seems less reliable, even though many websites make the claim. Duct cleaning services that include cleaning all of the other components of the system may be worth considering, but those claiming that duct cleaning alone will reduce energy bills should be avoided.
There is another issue as well. Most people who choose to have their ducts cleaned do so for health reasons. They expect cleaner air in their home as a result. Here are a few things to think about:
If the ducts are dirty, how did they get that way? There are three main ways this can happen:
- The registers and grilles were not covered during construction or remodeling, so sawdust, drywall dust, food and other debris ended up in the ductwork. This is not uncommon.
- The ducts were not sealed properly. Many duct systems were sealed with tape, which does a poor job and tends to deteriorate over time. Some contractors still use tape instead of duct mastic on the joints. If the ducts are leaky, dirt, dust, critters and other contaminants can get in.
- If there is not a working filter on the system, dirt can get in during normal course of living.
In some homes, all three of these possibilities can be identified. One problem with dust, dirt, etc. getting into your ductwork is that it is mold food. Organic matter plus a little moisture can lead to mold and other biological growth. This can be a real problem, especially for those with asthma or allergies.
The first thing to do is make sure the ducts are sealed and the filter is working well. There is no point spending money to clean the ducts if they will be contaminated again. Additionally, sealing the ducts is often a big energy saver.
If there is contamination in the ductwork – especially if someone has respiratory problems – cleaning the ducts is worth considering, particularly if you have metal ducts that are not lined with insulation on the inside. These ducts can be cleaned effectively. Ducts with insulation on the inside are more difficult to clean, and there is a risk of putting fiberglass into the airstream, which may be a health risk for some people. Similarly, if you have flex ducts, these too can be difficult to clean. Take care to avoid tearing up the inner liner, which would interfere with airflow and expose fiberglass to the airstream.
We have talked with people who are convinced that cleaning the ducts improved their health, and we have no reason to doubt them. However, it is unclear how much the other measures – sealing the ducts, cleaning the fan and coil, and replacing the filter – also contributed.
Overall, there is evidence that a comprehensive cleaning of the system, in conjunction with sealing all holes, cracks and joints, can have positive effects, but you can expect to pay more for this service.
This article was originally featured in Carolina Country magazine.