Only certified and licensed techs should be working on your system, ask to see credentials upon arrival.
Entire system should be inspected before any work is started.
You should know exactly what the tech will be doing while in your home. All pricing should be discussed and agreed on before any work is started.
System must be placed under negative pressure to prevent the spread of contaminates.
Properly cleaning of HVAC systems requires removing the sources of contamination. Source removal begins with the use of a agitation device designed to loosen contaminants.
Coils and your blower play a crucial role in the cooling process having them cleaned regularly is vital to your systems performance.
Plenums bring in, distribute, and remove air from your home.
Duct work should be disinfected and sanitized immediately after your air ducts are cleaned. Only chemicals registered with the EPA should be used in your system. Always ask to see the safety data sheet for any chemical a tech is using in your system.
Often forgot during air duct cleaning but your outside unit is just as important as your indoor unit. Condensers are under harsh conditions and can have an impactful effect on your systems performance.
Under any circumstances should you ever pay for your air duct cleaning in advance. The primary method to verify the cleanliness of the ductwork is a visual inspection.