What is Steam Cleaning?

The following is a direct copy of information from an INDEPENDENT CONSUMER ADVICE ORGANISATION, ( Choice ) 

Hot water extraction

Hot water extraction (also known as steam cleaning) is what the Australian standard refers to as 'periodic or corrective cleaning,' and is suitable for most carpets. It can be done with a truck-mounted or portable machine. The former is more powerful and will do a more thorough job. 
Manufacturers recommend hot water extraction as the preferred method of carpet cleaning to invigorate and prolong the life of the carpet. 

In the steam cleaning process:
  • The carpet is vacuumed.
  • A chemical is sprayed on and left to bond with the soil.
  • Afterwards water is injected into the carpet with a high-pressure jet spray.
  • Finally the water is vacuumed out.

Dry cleaning

'Dry' cleaning (some water is used though less than in steam cleaning), is what the standard refers to as a 'surface cleaning.' It's handy for areas that receive a lot of traffic and need a fast drying time. Dry cleaning can be used as a maintenance clean but it's still best to have hot water extraction done from time to time. 

Bonnet cleaning is the most-commonly used form of dry cleaning. In this process:
  • The carpet is vacuumed.
  • A cleaning agent is applied to the cleaner and sometimes the carpet and then they go over the carpet with the cleaner. The cleaner has a pad (the bonnet), which rubs the carpet, transferring the dirt onto the pad.
  • Finally the carpet is vacuumed