Register vents cleaning is $15-$19. We connected our vacuum machine to the access panel above the furnace. Than close every vent in the house and leave open just one what have to clean. Like that we have a vacuum but instead of pulling of air it blows inside vents into our vacuum machine. Then vacuuming, brushing and clean the vent area and the vent. Then use rotor brush to clean inside the duct all way long. After that blow dust with special pressure. Like that all dust and dirt gets to our vacuum machine. The cost of clean every event is $15 if in the house is 20 or more. And $19 if less than 20 vents.