Using a home equity line of credit to pay down credit card debt seems like a no-brainer: Pay 20 percent interest on the Visa balance, or slightly less than half that to the mortgage company, with the likely added benefit of tax deductible interest.

But experts caution that for most people there's a reason the debt got there in the first place. And for those who can't resist the temptation of a $0 balance on their credit card, or $40,000 in spending power, a home equity line may just make matters worse.

Quick fix can be fast trouble
"They can be a tool, if they lower your interest rate and you do get some tax credit for it," says Renee Rupe, education director in the Consumer Credit Counseling Service's Denver office. "But there is a whole population of people out there that ... because home equity loans are easy and accessible, they use that as a quick fix and then get into trouble again."

Rupe laments: "This is our credit counseling dilemma."

From a purely financial standpoint, the benefits of moving credit card debt to a home equity line are clear. In a nutshell, someone with a $10,000 balance on a credit card and an annual percentage rate of 18 percent would have to pay about $1,750 in interest over the course of one year, assuming monthly payments of $200. The same customer making $200 payments on a $10,000 home equity line at the 8.5 percent prime rate would end up paying slightly less than $800 in interest during the year.

Add in the tax deduction, and "there's just a huge differential," says Debralee Nelson, a vice president and senior retirement planner for Harris Bank in Chicago. "It's a great use of a home line."

Debt consolidation most popular use of home equity
Consumers have certainly caught on to those benefits too, according to a recent study from the Consumer Bankers Association. An overwhelming 40 percent of home equity line borrowers cited debt consolidation as their No. 1 reason for getting the loan, with home improvement running a distant second at 23 percent.

But problems arise swiftly for those who aren't careful, says Nelson.

"Lots of times, when people take out a home line, they see that they have a large amount of available credit," she says. "Their credit card debt is $10,000, and they are able to get a home line of $30,000, so the danger is that they'll say, 'That wasn't so bad,' and they'll run their credit cards up again."

Consumers should guard against the trap by cutting up and canceling all but one credit card after moving debt to the lower rate equity loan, says Rupe of the Consumer Credit Counseling Service. Or, to keep from having a problem at all, Rupe's group recommends limiting overall debt payments to no more than 20 percent of a person's after-tax income in any given month, not including what goes toward mortgage or rent payments.