6. Some things to know about Furnace and air duct cleaning

by | Furnace and Air Ducts

Man Cleaning the Duct

During a Home Inspection, I inspect for broken heat register duct pipes with my snake camera, I also take note of the cleanliness of the air ducts. Although there is no conclusive proof that dirty air ducts contribute to health problems, is the fact that most of the dust and dirt in the air duct system adheres to the pipes surface and seldom enters the living space. Also, the air that is circulated through the heating pipes normally would have gone through a filter first. Most of the debris and dirt I find in the heating vents has come from the room where the heating vent is, such as small Lego blocks, bits or small particles of drywall and debris from the construction process, etc. and on one occasion I found a teddy bear, and another, a tennis ball. That being discovered, I have not met a homeowner yet that would approve of a pile of dirt and debris in their heating system, it only seems natural that they should be cleaned and have this debris removed. At this point in my inspection, I have already inspected the furnace for proper operation and cleanliness which includes the fan, cleaning the furnace fan is somewhat more complicated. The furnace fan is a barrel type cage fan, somewhat like that of a hamster wheel, this fan is designed with concave or slightly bent strips of metal commonly called veins between the two bearing points around its perimeter, they scoop the air from inside the spinning barrel fan and propel it off its surface into the heating Plenum systems. If I notice these concave veins are coated with caked on debris and dust, I recommend a cleaning soon. This furnace cleaning should also include the return air and heat distribution system, such as register vents and all the connection points to them. I have done several tests with my anemometer (air flow meter) of a before and after a filter change, and I have noticed approximately 200 ft. per minute greater airflow with new filters installed than with the old dirty filters. That is approximately 24 cubic feet per minute, (cfm) greater airflow, combine this with a clean fan, and there will be an improved increase in the performance of your furnace.

Apart from a dirty fan and dirty supply air plenums, if accessible I check in and around the humidifier, which is generally located on the furnace Plenum in the basement. The humidifier is a wet zone within the heating Plenum system. Small amounts of water particles are pulled into the air system through the air movement through the humidifier. Some of these water particles can accumulate within the first few feet of the humidifier. These water particles can dampen any dust or debris that is stuck within the Plenum system, and with the right conditions the potential for mould and other microbial growth increases. All components of the furnace system need to be methodically cleaned. If some components are not cleaned or overlooked, they can further contaminate a freshly cleaned system. Check with your furnace cleaning service provider to ensure that all components will be cleaned thoroughly. It is not advisable to allow the cleaning service provider to apply any chemical cleaning compounds, encapsulants, sealants, or Ozone treatment to the inside of the ductwork or other system components. You should thoroughly research any claims made on these above procedures, and you should disallow any procedures that are not first approved by the governing regulatory body.

You can find companies that provide duct cleaning services online, from there you can check out their qualifications and reviews. Better than that, talk to your neighbours and friends and get their feedback on any companies that they may have dealt with in the past. You should be wary of any cleaning companies that make claims about the health benefits of duct cleaning, such claims have not yet been substantiated. Also, you should be wary of any duct cleaning companies who recommend duct cleaning as a routine part of their yearly heating and cooling system maintenance. Duct cleaning should be on a “as required basis.” Do not allow anyone to suggest that the use of chemical biocide’s or treatments are required for a proper cleaning procedure. Always check the companies references and consumer reviews to ensure there was no problems with the heating system after the cleaning. Ask the service provider if they have any specialty licenses or certificates related to their cleaning profession. And, always make sure that the duct cleaning service provides you with a written agreement that outlines the total procedure and items to be cleaned along with the final cost for the job.

Air Duct in a Building

Once you have made your decision on a furnace cleaning company, there are procedures that would suggest
they are a professional service provider. Some of these are;

  1. Cover furnishings and carpeting in the furnace area.
  2. Do a general inspection before the cleaning procedure to ensure there are no asbestos containing materials in or around the heating system.
  3. All vacuum equipment should use high efficiency or HEPA filters and exhaust to the outside.
  4. Have a controlled cleaning method with a smooth approach as to not damage or disconnect any connection points within the duct system.
  5. Flex duct system used by the humidifier would be easier to replace than attempted cleaning.
  6. Care should be taken in re-insulating and sealing up any access points or holes that the service provider used or made during the cleaning process.

Once you have had your ducts and furnace thoroughly cleaned, a good preventative maintenance routine is
essential to keeping them clean and minimize any future ductwork contamination. Some procedures to achieve
this are:

  • Use the highest efficiency filters recommended by the furnace manufacturer.
  • Check and change the air filters on a regular basis.
  • Operate the humidifier as recommended by the manufacturer.
  • Ensure that the filter and filter holder are tight with no gaps.
  • Regular home vacuuming and maintenance will help.
  • Dust that is produced by construction or renovation work should be sealed off to that area only.

Good housekeeping procedures, and a well-maintained furnace with yearly maintenance checkups, and with
clean air filters will help to ensure that you are breathing clean air