By Gene and Katie Hamilton
Before You Begin
A licensed duct specialist inserts a power-driven rotary brush that works itself all the way from the heat registers to the main trunk line. You can do a partial cleaning using a shop vacuum. But you can only clean as far as the vacuum hose can reach, so it's not nearly as effective as having a professional do the job.
Step 1 : Remove registers
Carefully remove registers by lifting the metal edges away from the wall or floor and pull them out and away. Some may be held in place with screws so a screwdriver is needed to remove them.
Step 2 : Remove duct screws
The hose of a standard shop vacuum is not long enough to reach all parts of the dust system. To gain access to sections that can't be reached remove the sheet metal screws near a convenient joint of the ducting and pull the joint apart.
Step 3 : Clean out the interior
Use a chimney brush to scour the inner surface or the ducts and remove the debris with a shop vacuum. The crevice tool will be the most effective attachment to use.
Step 4 : Reach into panned-off returns
The heaviest accumulation of dirt and dust is in the return air ducts or panned-off returns
that are joist spaces covered with sheet metal. To access these ducts remove the staples or tacks holding the sheet metal to the wood joists and peel it back so you can clean the area. When finished, reattach the sheet metal and close any gaps with foil tape.
Step 5 : Repair any holes
If you find any gaps or holes in the ducting, repair them by applying duct tape to the open joints and cracks.
Step 6 : Change the filter
Change the furnace filter at least four times a year, more if you have pets or if someone in the house has allergies.