Since my first-mortgage rate is very low, should I use a second lien/HELOC instead of a full refinance?
Often a second lien makes sense when your current rate is well below today's rates, because it lets you borrow against your equity without giving up that low rate. A cash-out refinance replaces the whole mortgage at today's rate; a second lien prices only the new money. Which costs less overall depends on your rate, the amount you need, your credit and your closing costs.
Last updated September 29, 2026How is a second lien different from a refinance?
A second lien, like a HELOC or home equity loan, is a separate loan with its own rate and payment. It sits behind your first mortgage, which is why it's also called a junior lien. A cash-out refinance pays off your mortgage and replaces it with one new, larger loan at a new rate. A second lien leaves your existing loan exactly as it is.
Does a second lien change my first mortgage?
No. Your first mortgage's rate, term and payment stay the same. The lender does look at it in two ways: its payment counts in your debt-to-income ratio, and its balance counts toward your combined loan-to-value, which sets how much equity you can borrow against.
Which option costs less?
It depends on three things:
- Rates: second liens usually carry higher rates than first mortgages, and HELOCs are usually variable. But the refinance applies today's rate to your whole balance, while a second lien applies its rate only to the new money.
- Closing costs: a second lien's costs apply to a smaller loan, so they're usually lower in dollars, and some lenders offer no-closing-cost HELOCs at a slightly higher rate. A refinance's costs apply to the whole new balance.
- Valuation: second liens more often use an automated value; a cash-out refinance more often needs a full appraisal.
It depends on your situation:
- Your rate is well below today's and you need a modest amount: a second lien keeps your low rate in place.
- You need a lot, or today's rates are close to yours: one cash-out refinance can cost less overall, even though you give up the old rate.
- Your credit is strong and you have equity room: a second lien is more likely to work.
- Your credit is fair, or equity is tight: a cash-out refinance may be the only option that works.
- You'll carry the money a short time: lower closing costs favor a second lien; a longer hold favors the lower rate of a first mortgage.
| Does my first mortgage change? | No |
|---|---|
| How the lender uses it | Its payment counts in debt-to-income; its balance counts in combined loan-to-value |
| Rate on a second lien | Usually higher than a first mortgage, often variable |
| Closing costs | Lower in dollars on a second lien, since the loan is smaller |
| Valuation | Second liens more often use an automated value |
Related questions
Sources
- https://www.consumerfinance.gov/ask-cfpb/what-is-the-difference-between-a-home-equity-loan-and-a-home-equity-line-of-credit-heloc-en-247/
- https://www.consumerfinance.gov/ask-cfpb/what-is-a-second-mortgage-loan-or-junior-lien-en-105/
- https://homebuyer.com/guidelines/freddie-mac/monthly-debt-payment-to-income-dti-ratio-5401-2
- https://homebuyer.com/guidelines/fannie-mae/combined-loan-to-value-cltv-ratios-b2-1-2-02
- https://www.lower.com/mortgages/heloc-vs-cash-out-when-you-have-a-low-mortgage-rate
- https://www.rocketmortgage.com/learn/cash-out-refinance-vs-heloc
- https://www.freedommortgage.com/learn/refinancing/cash-out-or-heloc
- https://www.bankrate.com/home-equity/heloc-rates
- https://www.wsj.com/buyside/personal-finance/mortgage/home-equity-loan-rates
- https://www.rocketmortgage.com/learn/home-equity-loan-closing-costs
- https://www.refi.com/learn/heloc-appraisal
- https://selling-guide.fanniemae.com/sel/b5-4.1-01/texas-section-50a6-loans
Sourced from licensed loan officers and brokers in the FreeRateUpdate network.
Educational information only, not individualized financial or legal advice. Program details and rates change; verify current terms with a licensed loan officer before making a decision.