This is the time of year to get your furnace cleaned, and the Michigan Department of Consumer & Industry Services (CIS) offers some sensible tips so that you don't get taken to the cleaners instead!

While most mechanical contractors are reputable, the furnace "scam artists" are on the move during the fall months. And unfortunately, hundreds of unsuspecting homeowners become victims of their fraudulent and unscrupulous activities.

In a recent case investigated by the CIS Bureau of Construction Codes, two mechanical contractors sold an elderly woman $30,000 worth of heating and cooling equipment. When they tried to sell her $7,000 more in unnecessary equipment, they were arrested, found guilty and given prison terms.

This and many similar stories could be avoided by knowing how to recognize questionable and potentially fraudulent contractors. Toward that end, the Bureau of Construction Codes offers the following tips:

Don't fall for phone solicitations that offer "low cost" or "free" furnace cleaning. Once in the dwelling, the worker will tell home owners their heating system has serious problems that require immediate attention.

Don't sign a contract just because the worker says you face possible illness or death if the furnace isn't replaced promptly. If told that your furnace threatens your health, ask for a written copy of the technician's test results and call your local gas company.

Don't hire someone who comes to your door with a Shop-Vac vacuum offering to clean your heating ducts. It won't do the job. A proper cleaning requires a high volume vacuum system and maybe even a steam process.

To get at least three independent written estimates from licensed local mechanical

contractors if a furnace repair or replacement is recommended. If you subsequently sign a

contract for work, make sure it stipulates that your final payment will be withheld pending the mandatory inspection by the local Building Department.

Do ask to see the mechanical contractor's license and write down the contractor listed on it. Verify the license by contacting the Mechanical Division of the Bureau of Construction Codes at (517) 241-9325.

Do maintain and prolong your furnace by cleaning air returns with a household vacuum cleaner and changing the filter at least three times during the heating season.

Do get your heating system thoroughly cleaned by a reputable, licensed, local mechanical contractor every two years.

Read more Michigan Department of Consumer & Industry Services press releases.