A HELOC and a second mortgage are different products, even though both let you borrow against your home's equity

A HELOC (home equity line of credit) and a second mortgage are not the same thing. Both use your home as collateral and both let you tap the equity you have built up. But they work differently, cost different amounts, and carry different risks.

The main difference: a second mortgage gives you a lump sum of money all at once, and you pay it back on a fixed schedule. A HELOC works like a credit card — you draw money as you need it, pay interest only on what you use, and can borrow again as you pay it down. A second mortgage is a closed loan. A HELOC is an open line.

Both are secured by your home, which means if you stop paying, the lender can foreclose. Both sit behind your first mortgage in the repayment order if your home is sold. But the way you access the money and the way you repay it are fundamentally different.

Key Takeaways

  • A second mortgage is a single lump-sum loan with a fixed repayment schedule; a HELOC is a revolving line of credit you draw from as needed.
  • Second mortgages typically have fixed interest rates and fixed monthly payments; HELOCs usually have variable rates and payments that change as you borrow and repay.
  • A HELOC charges interest only on the amount you actually borrow, while a second mortgage charges interest on the full loan amount from day one.
  • Both are secured by your home, so defaulting on either can result in foreclosure.

How a second mortgage works

A second mortgage is a traditional loan. You borrow a set amount — say $50,000 — and the lender gives you that money in one payment. You then repay it over a fixed term, usually 5 to 15 years, with a fixed interest rate and a fixed monthly payment.

Because it is a closed loan, you cannot borrow more once you have paid it down. If you pay off $10,000 of a $50,000 second mortgage, you do not get access to that $10,000 again unless you refinance or take out a new loan. The lender knows exactly how much you owe, when you will finish paying, and what your monthly obligation is.

Second mortgages are straightforward to budget for because your payment never changes. They are also faster to close — typically 2 to 4 weeks — because the lender is funding a fixed amount and the terms are set from the start.

How a HELOC works

A HELOC is a line of credit, not a loan. The lender approves you for a maximum amount — say $100,000 — but you do not have to use it all. You draw money when you need it, either by writing a check, using a debit card, or transferring funds online. You pay interest only on what you have actually borrowed.

As you pay down the balance, that money becomes available to borrow again. If you draw $20,000 and pay back $5,000, you can borrow another $5,000 without refinancing. This makes a HELOC useful for ongoing expenses or projects where you do not know the total cost upfront.

Most HELOCs have a draw period — usually 5 to 10 years — during which you can borrow and repay freely. After the draw period ends, the line closes and you enter a repayment period, typically 10 to 20 years, during which you can no longer borrow and must pay down the remaining balance.

Interest rates and monthly payments

Second mortgages almost always have a fixed interest rate. Your rate is locked in at closing and does not change for the life of the loan. Your monthly payment is also fixed and predictable.

HELOCs usually have variable interest rates tied to a market index like the prime rate. When the index moves, your rate moves with it. During the draw period, you may pay interest-only, so your payment is low and can fluctuate. Once the repayment period begins, your payment jumps because you are now paying down principal, and the payment amount can still change if rates move.

This difference matters for budgeting. A second mortgage payment is the same every month. A HELOC payment can rise or fall, and can rise significantly if interest rates climb or if you enter the repayment period.

Closing costs and fees

Both products charge closing costs, but the amounts differ. A second mortgage typically costs 2 to 5 percent of the loan amount in closing costs — appraisal, title search, underwriting, origination fees. On a $50,000 loan, that could be $1,000 to $2,500.

A HELOC usually has lower closing costs, often $0 to $500, because the lender is not funding a large sum upfront. However, some HELOCs charge annual maintenance fees or inactivity fees if you do not use the line.

Both products may charge prepayment penalties if you pay off the balance early, though this is less common now. Read the loan documents to know whether yours does.

Risk and foreclosure

Both a second mortgage and a HELOC are secured by your home. If you default on either one, the lender has the legal right to foreclose. However, the order matters: your first mortgage is paid first in a foreclosure. The second mortgage or HELOC holder is paid only if there is money left after the first mortgage is satisfied. This makes second mortgages and HELOCs riskier for lenders, which is why their interest rates are higher than first mortgage rates.

For you, the risk is the same: if you cannot pay, you can lose your home. This is true whether the debt is a second mortgage or a HELOC. Do not borrow against your home unless you are confident you can repay.

When to choose a second mortgage versus a HELOC

Choose a second mortgage if you need a specific amount of money now and want predictable, fixed payments. Second mortgages work well for a one-time expense like a home renovation, medical debt payoff, or education costs. You know the total cost, you want the money upfront, and you want to lock in your rate and payment.

Choose a HELOC if you need flexible access to money over time, do not know the total amount you will need, or want to pay interest only on what you use. HELOCs work well for ongoing home repairs, a business that needs working capital, or a situation where expenses will happen gradually. The trade-off is that your rate and payment can change.

Some homeowners use both: a second mortgage for a large, known expense and a HELOC as a backup line for emergencies or unexpected costs.

Frequently Asked Questions

Can I have a HELOC and a second mortgage at the same time?

Yes. Both are secured by your home and both sit behind your first mortgage. Lenders will look at your total debt and your income to decide whether you can carry both, but there is no rule against having them together. Your home's equity has to be large enough to support both loans.

What happens to my HELOC if interest rates go up?

Your interest rate will rise, which means your monthly payment will increase during the draw period. If you are in the repayment period, your payment will also rise. This is why HELOCs carry more payment risk than second mortgages — you cannot predict what you will owe in five years.

Can I pay off a second mortgage early without a penalty?

Most second mortgages allow early payoff, but some charge a prepayment penalty. Check your loan documents or call your lender to confirm. If there is a penalty, it is usually a percentage of the remaining balance or a set number of months of interest.

Is a HELOC easier to get than a second mortgage?

HELOCs often have slightly lower approval requirements because the lender is not funding a large sum upfront. However, both require a home appraisal, proof of income, and a credit check. Your credit score, income, and home equity matter for both.

What if I do not use my HELOC?

If you do not draw from your HELOC, you typically owe nothing. Some lenders charge an annual fee to keep the line open even if unused, but many do not. Read your agreement to know whether your HELOC has an inactivity fee.