Dehumidification (air drying) in an air conditioning system is provided by the evaporator. Since the evaporator operates at a temperature below the dew point, moisture in the air condenses on the evaporator coil tubes. This moisture is collected at the bottom of the evaporator in a pan and removed by piping to a central drain or onto the ground outside.
Manufacturers of products marketed to coat and encapsulate duct surfaces claim that these sealants prevent dust and dirt particles inside air ducts from being released into the air. As with biocides, a sealant is often applied by spraying it into the operating duct system. Laboratory tests indicate that materials introduced in this manner tend not to completely coat the duct surface. Application of sealants may also affect the acoustical (noise) and fire retarding characteristics of fiber glass lined or constructed ducts and may invalidate the manufacturer's warranty.

Equipment used to clean ducts varies widely. The cheaper the equipment used the more you are just wasting money. This is why it's typically not worth doing. In some situations it may be beneficial, but only after determining and investigating the duct system. This should be done by a licensed HVAC contractor and not a duct cleaner that typically do not hold and HVAC license. (Duct cleaners aren't required to be licensed in HVAC in many areas.)
If the system is sealed air-tight and a really good filtering system is in place then you should NEVER have to clean your ductwork. Most dust people see in their homes (on beds furniture etc....) is broken down insulation that is being blown into the home from the attic (venturi effect) where the duct bucket (box etc...) is not sealed at the sheetrock ceiling. On the return side, ANY leaks in the ductwork will pull hot attic air and dust into the system, clogging up everything.
What if you move into a 20 year old house and find that the people who owned it previously NEVER replaced the filter? It was so dirty that the HVAC system did not work at all. For most people - duct cleaning is NOT a waste of time or money. You must not have allergies. I have very bad ones plus asthma. It makes it very hard for me if I don't get it done every few years. By the way - the ducts get dusty just sitting there - especially without air going through them. Dust settles on them just like it does the furniture.

If no one in your household suffers from allergies or unexplained symptoms or illnesses and if, after a visual inspection of the inside of the ducts, you see no indication that your air ducts are contaminated with large deposits of dust or mold (no musty odor or visible mold growth), having your air ducts cleaned is probably unnecessary. It is normal for the return registers to get dusty as dust-laden air is pulled through the grate. This does not indicate that your air ducts are contaminated with heavy deposits of dust or debris; the registers can be easily vacuumed or removed and cleaned.

HRV/ERV Ventilators: These whole-house ventilators exchange air. They are ideal for homes with what is called a “tight envelope,” homes where house wrap has been applied and airgaps in the attic, around windows, doors and outlets have been sealed. Air in these homes becomes stale and polluted, so exchanging the air is important to IAQ. Heat recovery ventilators (HRV) are designed for cold climates. Energy recovery ventilators (ERV) are best for warm climates.  Your cost for an installed HRV or ERV will range from about $2,000 to more than $5,000 based on its capacity and features.
Central, "all-air" air-conditioning systems (or package systems) with a combined outdoor condenser/evaporator unit are often installed in North American residences, offices, and public buildings, but are difficult to retrofit (install in a building that was not designed to receive it) because of the bulky air ducts required. (Minisplit ductless systems are used in these situations.) Outside of North America, packaged systems are only used in limited applications involving large indoor space such as stadiums, theatres or exhibition halls.
Well, I had the cleaning done. The handler is definitely much quieter. It was explained to me that with the coils clean, the condensation will be able to sweat off instead of sticking to the dust and dirt, therefore the humidity (lots of humidity in florida) will be removed better. I feel as if it was worth it, but, I will definitely change that filter every 3 weeks or so from now on. I don’t want to pay that cost again.
I called a company name “GREEN RHVAC” with their $29.00 one system air duck cleaning. When the guy came with a truck I asked him to tell me how much he will charge and he said that if he gave me price and I didn’t want the service then he would charge me $89 or he would tell me how much he charge me after he finished the work. I immoderately sense that I made mistake to call him to my house. To cut my lost I asked him to give me the price and it was $1600 for two systems house. I paid $100 to him for my lesson to learn and search online to find this site is very helpfully and I should do it before to call anyone for air duck cleaning.
I have lived in Calgary for quite some time now. When I first moved here I couldn’t stand the humidity levels. Its like a desert come winter. When I first moved into my new home, the house inspector insisted I have my furnace and ducts cleaned. I was very sceptical about duct cleaning to begin with. The company I hired came on time and were very respectable from the start. Before mentioning anything they asked me what my concerns were and what issues I was having. They were more concerned about addressing my issues then bringing anything non related up. I ended up going with this company and getting a humidifier installed a couple days later after the cleaning. Its been almost 4 years now that I have been here. The humidifier is working great and the difference is incredible. They took me around explained step by step what they were doing and the reasons they were doing it. With all those other companies out there, I am glad I found them at this site.

As a homeowner and an owner of rental property I can tell you that the air ducts sometimes need to be cleaned. If you have had pets or anyone smoking in your home (even a visitor) for any length of time, having the ducts cleaned is really good idea. I had a tenant who did not smoke, but got married to a smoker more than year after moving in. When I realized someone was smoking I had them move out, but the smell was awful. I had the ducts cleaned and sanitized (it was a bit extra). The ducts were shiny like new afterwards. I left the windows open for a few days and we cleaned the place super clean and then replaced the carpets. The duct cleaning was worth every penny because the house looked, smelled, and felt new afterward. I plan to have my own house ducts cleaned again this year as we have two cats. We had them cleaned about 12 years ago and they found building materials in the ducts! If you move into a house that has never had them cleaned, it is good to do it. If you have allergies, clean the ducts to see if it helps. You never know what is in your ducts if you have never had them cleaned.


I took off stars for two reasons. Minus one star for issues trying to use the $50 for $25 voucher I purchased through Yelp. Although there was no minimum stipulated, the office wouldn't take it for the initial $59 diagnostic fee. If I used the 10% off First service that they offer, then they won't let me use the voucher on the actual repair bill.  I was stuck with paying the full $59 diagnostic fee.
Reinstall the access panel and disconnect block. Turn on the circuit breaker and furnace switch. Then set the thermostat to a lower temperature and wait for the AC to start (see “Be Patient at Startup,” below). The compressor should run and the condenser fan should spin. If the compressor starts but the fan doesn't, the fan motor is most likely shot. Shut off the power and remove the screws around the condenser cover. Lift the cover and remove the fan blade and motor (Photo 7). Reinstall the blade and secure the cover. Then repower the unit and see if the fan starts. If it doesn't, you've given it your best shot—it's time to call a pro.
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