Winter is a popular time for home improvements as leaks, drafty windows and water in basements become noticeable. Unfortunately, home repairs are among the most common sources of customer dissatisfaction, according to the Consumer Federation of America.

A few simple procedures will help in avoiding common problems, said Lou Morsberger, CEO of ValueStar, which tracks customer satisfaction for businesses in the San Francisco area.

The first step is to find out how long the business has been in operation by asking for a copy of its operating license. Home-improvement contractors survive on the merit of their work, so older firms are less risky. "The rule of thumb is the longer they've been in business the better," said Morsberger. "But look for at least two years in operation."

ValueStar also researches contractors' financial status to make sure they have the financial resources to finish the job and any follow up work. "You want to make sure that a contractor's going to be around for at least the next 12 months in case more time is required for the work or for additional services," said Morsberger.

Morsberger also recommends asking for three to five references from past projects. These should include information on the contractor's ability to meet project deadlines and estimates, without sacrificing quality.

If the references are positive, then ask for a detailed estimate of the work to be performed including materials needed, the completion date and possible reasons why more money might be needed.

"The customer needs to sign off on any changes that require more money and materials than what was in the original quote," said Morsberger. "And never pay in full until the work is completed according to the original specifications."

Finally, make sure that the contractor has proper insurance. Without workers compensation, the homeowner is liable for injuries on the job. ValueStar also recommends that contractors have at least $1 million in general liability to cover any damages that results from accidents.

"You don't want to be on the hook if the contractor breaks a pipe while working and floods your house," said Morsberger. "Make sure they have the insurance they need to clean up any accidents, or else it falls to you to deal with the problem."