CHICAGO (CBS) — With colder weather approaching, it’s time to think about heating your home.

The Citizens Utility Board has a warning if you’re thinking of switching to one of the alternative natural gas suppliers.

CUB’s Jim Chilsen says you might want to think twice before going with an alternative gas company.

He says CUB’s Gas Market Monitor looked at 9,000 plans and found 94 percent of them were “money losers.”

Chilsen says, “Chicago area utility prices [for People’s Gas, North Shore Gas and NiCor], right now this month, are at their lowest point in nearly 15 years.

“So CUB’s analysis clearly shows that, shopping for a gas supplier in the Chicago region is a gamble that you’re likely to lose.”

Chilsen calls those findings, “startling.”

If you are approached by an alternative natural gas company, Chilsen suggests you read the fine print before going with it.

Customers need to to know whether the company charges a fee for leaving before the plan’s termination date.

Also, don’t give to representatives of alternative natural gas companies copies of your gas bill or your account number.

Those are sometimes used by unscrupulous companies to switch your account to them without you realizing it or approving it.