Air Conditioning (HVAC) Ducting Explained - A Complete Guide For Any Air Conditioning Buyer

There are heaps of different types of air conditioning ducting available on the market. Below is a list of the most common forms of ducting with a description of what they are used for.

Reverse Cycle Air Conditioning Ducting

Reverse cycle (refrigerative) air conditioners use duct that should be insulated with at least 2 inches of material surrounding the core. Speak with you air conditioning salesman to ensure this is the case. Duct insulated with less than 2 inches will lose it's cool/heat quicker.

Evaporative Air Conditioning Ducting

Evaporative ducted systems usually use duct with only 1 inch of insulation surrounding the core. This is because the air in an evaporative air conditioner is extremely fast moving and therefore there is little time for the heating/cooling effect to be removed. Evaporative ducting is generally bigger in diameter than reverse cycle ducting.

Acoustic / Whispaflex Air Conditioner Ducting

Acoustic ducting (or whispaflex as it is also known) is often used in the return air of a ducted reverse cycle system. The inner core of acoustic ducting contains many tiny holes that reduce the noise inside the ducting. The return air grille on a reverse cycle system can be quite noisy so this ducting helps reduce that noise. Once again it pays to ask the salesman to see if this ducting will be included in your system. If it is not included in your quote and noise is a major concern for you, consider asking for acoustic ducting to be included.

Air Conditioning Ducting Insulation Types

Air conditioning ducting can be insulated using a few different materials. These days polyester is a standard insulation material. Polyester is the same fiber as used in many people's pillows so it is quite a safe product. Fiberglass was also a common duct insulation type but less and less people are using it these days due to the high cost and the increased safety precautions needed to handle fiberglass products. All in all both types of insulation are more than adequate for residential duct work.

Air Conditioning Ducting Fire Retardancy

All ductwork should come with documents describing the products fire rating. In general most insulation acts as a fire retardant. Ask your air conditioning salesman for the documents to make sure that the duct you are buying conforms to the fire laws in your local area.

Warranties and Life Spans For Air Conditioning Ducting

Most ductwork will have a warranty aging from 5-10 years. Be wary of any manufacturer that does not offer this. After around 10 years ductwork starts to become quite aged. If you were to go up in your roof after this period, you would find the ductwork has become quite cracked and brittle. However, as long as you are still getting adequate airflow and the ducts are clean and unbroken you can still use the system. The biggest danger to ductwork is rodents like mice and rats who sometimes eat away the insulation and leave their waste in your ductwork.

Ductwork can also be a major source of illness. Bacteria can build up in ductwork over time that can make you and your family ill over long periods of time. There are products available however that you can place in your ducting to disinfect the system. You can also manually clean the inside of your ducting but this would be a long and arduous task. Perhaps consider simply replacing the ductwork around every 7-8 years if your health is a major concern.

So now you know the different types of air conditioning duct and what to look out for. Be sure to ask your air conditioning salesman what types of duct you will be getting with your air conditioning system.