Provided below is a combined step by step description breakdown of what you can expect from a professional air duct cleaning company.
Step 1: Marked Vehicles
Technicians should arrive at your home with a clearly marked truck. The company vehicle can be of several different sizes depending on the type of negative pressure (vacuum) that will be used.
The reason you want them showing up in a marked truck is that in this industry there are many dishonest individuals that use a reputable companies name and pretend to clean under their name.
Step 2: Certified Technicians
The service provider should send individuals who are trained as ASCS (Air Systems Cleaning Specialist) by NADCA (National Air Duct Cleaners Association). This ensures that you’ll receive the best possible service in the industry.
You can still get a professional cleaning from someone that is NOT an ASCS. However, most certified ASCS technicians are more knowledgeable in the industry giving you greater peace of mind.
Step 3: Pre-Cleaning Assessment
The technicians should complete a walk-thru of your home as part of the pre-cleaning assessment. This will be the best time for your questions or specific needs.
This is your best chance to turn the company around if you don’t feel comfortable with their equipment or confidence in completing the work professionally.
Step 4: Equipment Entry
In almost all cases a door or window will need to be left open to allow the hoses entry into the home. Protective drop clothes and corner guards should be placed under all vacuum hoses and equipment.
Some companies use a truck-mount vacuum where a door or window needs to be open at least 8 inches in diameter. If they have a portable unit it would just be a few inches the door remains open.
Step 5: Turning Furnace/Unit Off
The furnace should be cycled prior to the start of the cleaning. Once the system is confirmed to be working properly, power should be shut off.
It could happen to you that after a complete cleaning (including the furnace blower and motor) that the system doesn’t operate as normal. This is why it’s best to test with the technician to confirm everything is working before they start. Once confirmed all in well they should turn off the breaker to protect the machine and themselves.
Step 6: Access Panels
Access openings must be created to allow the extraction of dirt and debris to the vacuum. These openings will need to be cut to size, most openings are 8 -12 inches in diameter.
This will be different from one company to another. Some use rectangles (old style and don’t recommend). While most use circles, the very minimum in size should be 8 inches. A diameter smaller than 8 inches will not create enough negative pressure.
Step 7: Cover Vents
Supply and return vents should be covered or blocked. This action will increase negative pressure and prevent possible blow back’s from occurring.
Make sure the company you hire does this step! It’s often overlooked and a short cut for them without the client knowing the difference.
Step 8: Cleaning Branches
They should be starting from the highest level of the home working downwards. Once they are ready to clean, it’s important each grill/cover gets removed. Once the vent branch is exposed they should send a high powered whip or brush through each vent. The cover needs to be restored to maintain pressure before advancing.
The supply branches usually self-clean themselves (That’s why we have dust in our home) so just high-pressure air would be sufficient in most cases. However, for the maximum cleaning of the supply vent, a whip or brush should be used.
Regarding the return branches, a whip or brush is always required.
Step 9: Cleaning Main Lines
Once all supply and return branches have been properly cleaned, most of the dirt has already been extracted. However, the main lines now require cleaning to finish the process. The procedure is similar to the cleaning of branches where whips and brushes should be used to dislodge all remaining dirt and debris.
This is where most air duct cleaners can do a decent job, but a homeowner needs to verify that they got them all. It’s common for the quick cleaners to skip other important main ducts located in the bulkheads or at the split of the main channels. Lastly, make sure they didn’t contaminate your furnace during the process, they should have used a zone bag which insolated the furnace.
Step 10: Verification
Once all cleaning steps have been performed, a visual inspection of the system should be taken to verify all dirt and debris have been removed. Most companies will use a mirror and flashlight, while it’s becoming increasingly common to use a smartphone.
I would recommend if you ask to see the “before and after” the mirror and flashlight is the best option. You are able to move the mirror around and see all the angles. If the flashlight is strong enough you could see 40-50 feet with a decent size mirror. The coverage on a smartphone is very limited.
Step 11: Disinfection (Optional)
First check the biocide label, which will describe its range of approved uses. If you decide to permit the use of a biocide, the service provider should apply the biocide only to un-insulated areas of the duct system after proper cleaning. To apply the product it should be administered with a pressurized fogger to the supply/return plenum.
We recommend skipping this service unless excess amounts of dirt and debris have been found inside your ventilation system. If you trust your techininan ask their option based on your air ducts.
Step 12: Access Panels – Closure
All Openings are sealed with semi-permanent enclosures that can be used for future cleaning. These sheet metal plates come in many different sizes depending on the access opening required.
These access doors should be zipped screwed and sealed with aluminum tape. We don’t recommend them using duct tape, which will dry and peel off within a few months. Aside from the access door, other smaller holes are created for cleaning and should be closed off with 1 inch-2 inch rubber plugs.
Step 13: Turning Furnace/Unit On
The final step would be to turn the system back on to make sure everything is functioning properly.
Should they have professionally cleaned your blower and motor it would of been removed, it’s best to make sure everything is running normal before the company leaves.