All of you have dentists, you have doctors, you have preachers, you have mechanics. You don’t have to know everything about everything but you have to have people in your life that you can trust. Don’t just open up the phone book and pick a mechanical (HVAC) contractor. Call your friends and family and ask for referrals. There are no black and white (scam or not a scam) answers here.
I am a service technician [since '92].....and as to double filtering.....I have never recommended it. Granted.....it would be noticeably helpful if the fiberglass filters are the main ones used [which I also never recommend.....as long as system can deliver appropriate air flow with a pleated cotton filter...and any decent service tech can check the air flow for proper cfm]. Any particles small enough to pass through a pleated cotton filter are going to pass through a second filter as well....unless the second filters are so tight that the system is starving for air flow. Has anybody ever accidentally put two filters in their automatic drip coffee maker? What if cars used two fuel filters or air filters? I have told some homeowners to try using second filters at each register [the black thin filter material cut-to-fit....same type used in many window air conditioners].....but I only suggest this when I know they will still get at least 400 cfm per ton of air flow [350 absolute minimum]......as some homeowners know others who say it has helped and it gives them a peace of mind knowing they are doing something to help contribute to a solution, so it HAS to help [even though I think it falls in the "one-born-every-minute" category.....similar to duct cleaning].

A thorough visual inspection is the best way to verify the cleanliness of your heating and cooling system. Some service providers use remote photography to document conditions inside ducts. All portions of the system should be visibly clean; you should not be able to detect any debris with the naked eye. Show the Post-Cleaning Consumer Checklist to the service provider before the work begins. After completing the job, ask the service provider to show you each component of your system to verify that the job was performed satisfactorily.
On the other hand, if a service provider fails to follow proper duct cleaning procedures, duct cleaning can cause indoor air problems. For example, an inadequate vacuum collection system can release more dust, dirt and other contaminants than if you had left the ducts alone. A careless or inadequately trained service provider can damage your ducts or heating and cooling system, possibly increasing your heating and air conditioning costs or forcing you to undertake difficult and costly repairs or replacements.
yes get a good company and pay the price, I found so much dust and dirt and wood and paint chips and bugs and even bottle caps in my ductwork. I hired a major plumbing company who cleaned ductwork and i will say they did an excellent job cleaning my vent. they did miss one point in my ductwork because i still started to see dust all over my furniture and i realized that my retunduct work that was connected with a piece of sheet metal beam which was 16" across , the contractor that built my condo used a 16" wide sheet of sheet metal to connect the vent system to my return for the air to return back into my condo. The contractor should have built a 8" x16" square duct by 6 feet long to connect my intake to my return instead of using a sheet of sheet metal 16" wide by using two 3' sections by 16 inches wide. That was a shor cut which caused a major problem fir me.
2. If air quality is so important and duct cleaniliness is so uncertain, why not adopt doubling filtering; that is, in addition to the existing main furnace filter, add a filter at each air outlet. I understand replacing so many filters would be a burden, but air outlets can be designed for easy filter replacement. The builders and home design engineers should bear responsibility to provide good and low maintenance homes, rather than prioritizing on fancy or costly featuers for homes.
I did the $49.00 Groupon they just left. Basiclly all they did was stick a shop vac type hose into the vent supply and one return. I also had the dryer done. the person in charge pointed to the main return inside my humidifier and said it needed cleaning. I explained that I was in facility maintaince and would deal with it myself. After that they finished the vac and didn’t try any other sales pitch. I should have read the reviews before I bought this wast of money and time.
I thought the price advertised at 129.95 for duct cleaning was great and called to clean our ducts. When they came in to do the the job I could not be home and my wife dealt with them. My wife ended up paying 954.00. They convinced my wife that there was 1.5 inches of mold built up on the Evaporators and coils. It is not the money, my wife could not go to the basement to witness the mold build up or the coil fouling. We have not cleaned our ducts for at least 10 years. The last price we paid for our duct cleaning was 150.00. My concern is that they told my wife not to turn on the heat for 2 hours due the strong chemicals they used to kill the mold. Are these chemicals approved as safe?
I to had an odd layer of white'ish dust building up especially during seasonal periods when the HVAC ran a a lot. I carefully swept up the fine dust into a small pile and had it analyzed. Turns out it was very fine fiberglass powder dust. It turns out it is the insulation form the attic! (My attic has blown in insulation). Turns out if you (I) had small gaps around my HVAC registers in the ceiling whee the airs blows into the room. What occurred in my case was that the exiting air at that seam creates a vacuum effect at the grate vent cover and draws and then blows fine insulation dust from the attic into the house. Removing each register grate and sealing each tin outlet gap with calking between the dry wall ceiling and tin fixed the issue. A couple were so bad with bowed gaps I had to screw down the bowed tin to the attaching stud better. Checking the very same glass top desk that catches and shows any dust accumulation now shows only very small amounts of normal house dust build up over several weeks. A big, big improvement. You might have a look by simply removing a couple vent covers yourself.
2. If air quality is so important and duct cleaniliness is so uncertain, why not adopt doubling filtering; that is, in addition to the existing main furnace filter, add a filter at each air outlet. I understand replacing so many filters would be a burden, but air outlets can be designed for easy filter replacement. The builders and home design engineers should bear responsibility to provide good and low maintenance homes, rather than prioritizing on fancy or costly featuers for homes.

I just had my blower module replaced because my AC coil was frozen over. The underside of my coils had a thick mat of dust because I had never had it cleaned. I cleaned it myself by using a soft brush attachement on a shop vac. The inside of the blower appears to have a white/green growth, and I am sure the ductwork of my 30 year old house can’t be in good condition.

Demonstrate visible evidence of microbial growth in your duct work. Some service providers may attempt to convince you that your air ducts are contaminated by demonstrating that the microorganisms found in your home grow on a settling plate (i.e., petri dish). This is inappropriate. Some microorganisms are always present in the air, and some growth on a settling plate is normal. As noted earlier, only an expert can positively identify a substance as biological growth and lab analysis may be required for final confirmation. Other testing methods are not reliable.


I’m having my duct work cleaned this Saturday. Have a coupon for $49 through Amazon. Job normally $249. Had my basement remodeled about 18 months ago. The contractors were very thorough at blocking the vents, as far as I can tell. The offer is for HVAC and dryer vent cleaning. My house is 11 years old. I figured, $49 is not much. I appreciate your tips on not getting talked into any additional service, not to use solvents to clean, the certification information and before and after pictures. Very useful and I’ll be sure that all I spend is the $49 for the voucher.
On the other hand, if a service provider fails to follow proper duct cleaning procedures, duct cleaning can cause indoor air problems. For example, an inadequate vacuum collection system can release more dust, dirt and other contaminants than if you had left the ducts alone. A careless or inadequately trained service provider can damage your ducts or heating and cooling system, possibly increasing your heating and air conditioning costs or forcing you to undertake difficult and costly repairs or replacements.
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