Imagine that you had a credit card that allowed you to charge large amounts — we’re talking four or five figures — but only required you to pay back minimal amounts each month for a decade.

A dream, right? No, that’s roughly what an interest-only HELOC is like. You specify a particular repayment plan when opening this home equity line of credit, which means that for the first several years you only have to pay interest on the money borrowed and not the principal.

HELOCs aren’t interest-only forever, however. While this approach can make borrowing quite affordable initially, it can set you up for a shock later on, when you do have to start paying principal. So it’s important to understand what you’re signing on for.

What is an interest-only HELOC?

A home equity line of credit, or HELOC, is a revolving line of credit secured by the equity in your home (the portion of your home you own outright, clear of your mortgage).You can borrow against this ownership stake, to fund home improvements, pay bills or even make investments. Because HELOCs are secured (backed) by your home, they typically offer lower interest rates than other forms of financing.

The HELOC offers a revolving balance, like a credit card; but unlike a credit card, it doesn’t exist indefinitely – it has a set timespan, like a regular loan. “Interest-only HELOC” is essentially a phrase that refers to the line of credit during its first several years. This phase is called the draw period — you’re free to take funds from the line of credit and simply make interest-only payments in return. The draw period is normally five, 10, or 15 years, with 10 being the most common.

When the draw period ends, the HELOC repayment period begins and continues for typically, 10 to 20 years more. You can no longer borrow money; instead, you have to repay what you owe, as on a mortgage.The minimum monthly payment then includes principal and interest, and the payments are large enough to cover the remaining interest and pay off the loan by the end of the loan term.

Nowadays, there are still some HELOCs that require both principal and interest payments right away. Some lenders don’t like to offer them, or they may limit them to borrowers with stronger credit profiles. Bu these are few: Interest-only has gotten to be a standard option.

How does an interest-only HELOC work?

With an interest-only HELOC, you’ll push off making payments on your principal until after your draw period expires. All you’ll be paying is the interest. To calculate your monthly payment, use this formula:

Let’s say you’ve drawn $15,000 against your credit line, and your annualized interest rate is 8 percent. Your monthly payment would be $100 a month ($15,000 x .08 ÷ 12).

But all good things come to an end. If you have an interest-only home equity line of credit with a 20-year term and a 10-year draw, for example, then the loan becomes self-amortizing after 10 years. Over the remaining 10-year repayment period, you can no longer draw against the line of credit, only make repayments.

By going interest-only, you’re essentially shortening your repayment term — the amount of time you have to pay off the amount borrowed. That means your HELOC monthly payments will increase once your draw expires in order to pay off the loan in time. By a lot.

Also, be mindful of your HELOC’s variable interest rates. If they rise just as you enter the repayment period, your monthly obligation could really skyrocket.

Pros and cons of an interest-only HELOC

There are benefits and drawbacks to using these lines of credit.

Pros:

• Lower payments initially: Since you’re only paying off the interest at first instead of principal and interest, you have a lower monthly payment.
• Flexible borrowing: You take out as much or as little as needed during your draw.
• Cheaper financing: Your interest rate could be lower with an interest-only HELOC relative to credit cards.
• Tax benefit: You can deduct interest payments made to your HELOC on your tax return.

Cons:

• Adjustable rates: Your monthly payment can fluctuate based on market conditions.
• Lack of availability: Not all lenders offer interest-only HELOC loans, making them more difficult to come by.
• Higher payments down the road: Once your draw expires, you have to repay the principal too, resulting in higher monthly payments in the latter half of the loan repayment.
• Your house is at risk: If you default on your loan, the lender can foreclose on your home.

When does an interest-only HELOC make sense?

Going the interest-only route with HELOCS works if you:

• are strapped now, but expect to increase your household income in the future
• have a considerable amount of home equity built up
• think interest rates are trending down long-term
• plan to move before the draw period runs out (somewhat akin to the strategy of an adjustable-rate mortgage). You’ll have to settle up when you sell, but presumably your proceeds will cover the balance due.

When should you avoid taking out an interest-only HELOC?

An interest-only HELOC won’t make sense in some situations and could even be a risky decision if you are not financially prepared for the repayment structure. Here are some of the scenarios in which an interest-only HELOC may not be right for you.

Limited home equity

If you don’t have a lot of equity in your home, it won’t be an option for you. Any type of HELOC is primarily dependent on your home’s equity. Percentages vary by lender, but most will only let you borrow up to 80 or 90 percent of your home’s value.

Low credit score

Another reason to avoid an interest-only HELOC is if your credit score is low. You may still be able to get a home equity line of credit with less than perfect credit, but the interest rates will be higher. This means that you’ll have to pay hundreds if not thousands of dollars more over the course of the loan.

Repayment concerns

You should also avoid an interest-only HELOC if you aren’t confident you can make larger payments once the repayment period arrives or if the interest rate — which is variable — rises. Know how long your loan’s draw period is and make plans for how you’ll continue paying off the HELOC once your monthly payment increases. This might be several years down the line, depending on the terms of your HELOC, and requires careful financial planning.

What are alternatives to an interest-only HELOC?

Not everyone is comfortable taking out a HELOC. After all, failure to make the payments can result in a foreclosure on your house. Here are some alternatives.

Home equity loan

A home equity loan is similar to a HELOC in that you are borrowing against the equity in your house. But instead of getting a line of credit that you can draw against and reuse as you repay it, you get a lump sum. Your rate is fixed and so are your monthly payments. Rates on home equity loans tend to be a little lower than they are for HELOCs.

Personal loan

You can take out a personal loan from your bank or credit union or an online lender. Your credit score largely determines what your interest rate will be. If you can get a loan with a low interest rate, it can be a good alternative to borrowing against your house because it doesn’t come with the risk of foreclosure. If the interest rate on your personal loan is much higher than the rate you could get with a HELOC, a personal loan might not be a great option.

Mortgage refinance

Refinancing your mortgage replaces it with one that carries a better rate or payment terms. Your monthly payments will even go down if you’re able to secure a lower interest rate. Just keep in mind that you’ll be extending the number of years you have to pay a mortgage. A mortgage refinance usually won’t get you any money upfront but can give you more money each month.

Cash-out refinance loan

With a cash-out refinance, your new mortgage will be a bigger sum than your current mortgage, and you’ll receive the difference in cash. This can be a good option if you’re looking to get a lump sum upfront. And if you’re refinancing with a lower interest rate, your monthly payments may not even go up.

What should I do when my HELOC draw period ends?

Here’s a step-by-step guide for what to do when your HELOC draw period is closing:

1. A few months before your HELOC draw period ends, look at the balance on your line of credit. Determine how much your monthly payments will be and how you’ll need to adjust your budget to account for that.
2. Once your draw period ends, update your monthly payment to the new amount.
3. If the new (higher) monthly payment is a financial burden, it’s better to reach out to your lender than to stop making payments. Your lender may offer options like increasing the amortization length, which will lower the monthly payment.
4. You could consider refinancing your mortgage, getting a personal loan or getting cash out from your home equity.

The bottom line on interest-only HELOCs

During the initial draw period of an interest-only HELOC, your monthly payments are relatively low because you’re only paying interest. Once your HELOC draw period ends, you’ll be required to start paying down the principal as well. This means that your monthly payments will go up, possibly significantly.

An interest-only HELOC can make borrowing more affordable initially. But remember, those minimal payments don’t last forever. When the draw period ends, you will be responsible for repaying principal and interest. Before proceeding, be sure your budget can accommodate this type of repayment plan.