Do a quick online search for carpet cleaning and you’ll find a variety of different methods. The two most common are hot water extraction — mostly known as steam cleaning — and hot carbonation, often referred to as dry chemical techniques.

So how do you decide which method is best? To start, check the paperwork that came with your carpet, with the carpet manufacturer themselves or with a reputable carpet cleaning company. The most widely accepted cleaning method is hot water extraction.

“The high temperature of the water kills bacteria and extracts the dirt out of the carpet,” said Tony Solis of All Points Carpet Care in Mooresville, N.C. “It’s a very deep cleaning compared to dry cleaning.

Solis uses truck-mounted equipment that injects water heated between 180 and 250 degrees into the carpet under pressure and then rinses out a pretreated solution he sprays onto the carpet.

Steam cleaning removes bacteria, dust mites and odors. The most common drawback is a long dry time. Done well, carpet should dry in just a few hours.

“Drying time on a carpet should be four hours, not 44 hours,” Solis added.

If inferior equipment is used for steam cleaning, dry times can take more than a day — resulting in a mildewy smell — and soap can be left behind, attracting more dirt.

“If the technician leaves soap in the carpeting, you can tell when a customer has that happen to them. It seems like, within a week or two, the carpet seems dirtier than before they had it cleaned.”

Though most carpet types can withstand both methods, always follow the cleaning recommendations of your carpet manufacturer to ensure you don’t void the carpet’s warranty.

Some companies charge by the room, others by the foot. However a company charges, you should know what the fee will be before the technicians begin the work. Ask for a written quote, if it’s not offered to you upfront.

Most carpet cleaning jobs start at about $79 to $99 for one or two rooms and go up from there. Look for a company with a good history and that carries workers compensation and liability insurance and has an affiliation with an industry trade association like the Institute of Inspection Cleaning and Restoration Certification (IICRC) or The Carpet and Rug Institute.

A common complaint, according to Angie’s List reports, is companies that offer a discount and then try to up-sell for additional services not covered in the discount once they get in the door.

“They should understand (what) their bill (is) before any work is done,” Patterson said. “I invite customers to do as much research as they can on carpet cleaning because there are huge differences on carpet cleaning. It’s not just about price.”

Angie Hicks is the founder of Angie’s List, a resource for local consumer reviews on everything from home repair to health care at www.angieslist.com/