Turning home-equity debt into credit-card debt sounds like a dumb move. After all, it s conventional wisdom that you should do the reverse: Consolidate credit-card debt into a home-equity loan, because home-equity debt is generally cheaper than credit-card debt, especially when you factor in the tax deduction you get for home-equity interest.

But under the right set of circumstances, transferring home-equity debt to a credit card however contrarian can save homeowners big money. When the numbers are right, meaning the interest rate is lower on a credit card than on a home-equity loan and you can afford the credit-card payments (more on that below), carrying credit-card debt is in fact safer than owing money to your mortgage lender, says credit expert Gerri Detweiler, author of The Ultimate Credit Handbook. "If you're delinquent, a lender could move to foreclose with a home loan," she says. "With a credit card, it would move to collections and, yes, you could be sued, but they can't take your house."

That said, such maneuvers aren't for everybody. You have to play by the rules and be aware of the potential traps. Here's what you need to know.

Be ready to make higher payments

Turning your home-equity loan or line of credit into credit-card debt will quickly backfire if you can't afford the new payments. And they will be higher. That's because home-equity loans or lines of credit are typically amortized over 10 or 15 years, while credit-card minimum payments use a shorter horizon.

Say, for example, you have a $10,000 home-equity loan. Assuming it's a 10-year loan, your monthly payment will be $101. (We crunched the numbers in our mortgage calculator.) But if you transfer the balance to a credit card that requires a 4% minimum payment, your first monthly payment would be $400. (As you pay down the balance, those minimum payments will go down.) So before you sign up for a balance transfer, call the card company and ask them what your first payment would be.

Pick the right offer

First things first: If you're going to hand a massive balance over to a credit-card company, it's best you do it with a balance-transfer offer that promises a fixed rate for the life of the balance. Temporary ultralow-APR offers may look tempting, but be careful. Those typically last for only six to 12 months. Once the promotional rate expires, you'll be hit with the card's regular interest rate, which can run 18% or higher.

Also pay attention to the credit-card limit. Aim for at least twice the balance on your home loan, Detweiler recommends. This way, your credit score isn't likely to drop because of high utilization. (One of the factors that can bring your credit score down is to carry balances that are close to your available credit limits. More on this here.)

Comparison-shop

When comparing different balance-transfer offers, look for one that has no balance-transfer fee or a flat-rate fee. In some cases, fees can run as high as 3% or 4% of the transferred balance, with no limit. In other words, you could pay $300 or $400 on a $10,000 balance transfer. (For more on this, read our story. To see how that fee will affect your actual interest rate, crunch the numbers in our calculator.)

And don't forget the tax break when comparing the interest rate on a credit card to that of your home-equity loan or line of credit. If your loan rate is 6.5%, for example, and you're in the 25% tax bracket, you're essentially paying 5.04%. (Crunch your numbers here.)

Don't be late

Once the loan is transferred, make timeliness your biggest virtue. Even one late payment will trigger a rate hike to the credit card's regular interest rate or, worse yet, its penalty rate. Your best bet: Set up an automatic online payment schedule through your credit card or bank. If you had a HELOC, don't close the line of credit after you pay it off. This way, if your rate spikes up, you can always transfer the debt back into your home, Detweiler says. (You can't do that with a home-equity loan, though.)

Retire the card

Assuming you are using a new credit card, put it in a drawer and forget about it as soon as the transfer is done. (If using an existing card, make sure any previous balance is paid off before transferring a new one.) That's because if you use that card for purchases, those will start accruing interest at the regular rate. The reason: Banks apply all payments to the balance that carries the lower rate first. You may end up handing over whatever you saved on that balance transfer right back to the company that made it possible.