Health care expenses can be a huge drain on retirement wealth. A 2017 Fidelity report estimates that the typical 65-year-old couple retiring now will spend $275,000 on health care in their later years, not including long-term care.

There’s a better alternative to tapping your retirement accounts to cover future health care expenses – health savings accounts. HSAs come with a triple tax break: a deduction for contributions, tax-free growth and tax-free withdrawals for qualified health care spending.

Too many HSA savers, though, aren’t using their plans to their full advantage. According to the Employee Benefit Research Institute, 96 percent of HSA owners keep their accounts in cash. Although it can provide security in a volatile market, cash may be undercutting your HSA’s growth potential. A better use of an HSA is as a long-term savings vehicle, with investments like those found in an individual retirement account, while still retaining just enough cash for short-term expenses.

What you don’t know can hurt you. Several factors hold investors back from investing in their HSA. First, “there’s a general lack of awareness that people have the option to invest,” says Josh Jalinski, president of Jalinski Advisory Group and CEO of Wealth Quarterback in Toms River, New Jersey. “It’s not that they don’t want to take any risk with the account; it’s that they don’t know they can.”

Jalinski says HSA providers often give little guidance about what account holders can invest in or how to purchase investments. Companies that frequently change HSA providers only adds to the confusion. “Even if someone knew investing was an option, they may not be able to act on their desire, given the regular turnover of providers.”

A reluctance to invest through an HSA reflects a common mindset many investors have about these accounts. “Most people view HSAs as a short-term funding vehicle for health care expenses,” says Jamie Hopkins, co-director of the Center for Retirement Income at the American College of Financial Services in Bryn Mawr, Pennsylvania. “For someone who doesn’t have a lot of savings or flexibility in budgeting, that can be an effective strategy.”

But if you can afford to invest for the long run, tax-free growth is the best feature of HSAs. Passing on that growth allows inflation to chip away at those funds, says Robert Baltzell, president of RLB Financial in Los Angeles. “By putting money into a cash savings account, you can consider yourself safely going broke.”

Weigh the growth effect. Even modest returns from an HSA can add substantially to your overall retirement wealth. For example, consider an HSA owner who contributes $3,450 – the maximum allowed for an individual in 2018 – to the account each year for 30 years. “They’d accumulate just over $100,000 in contributions, and assuming a 4 percent return, that would double over that time horizon to more than $200,000,” says Michelle Herd, senior client advisor at TFC Financial Management in Boston.

At age 55, HSA owners can make catch-up contributions, similar to a 401(k) or IRA. Assuming you stay healthy and max out your plan contributions each year, you could have a sizable amount of money in reserve to pay for health care in retirement.

That’s particularly important for combating the effects of rising health care prices. “Inflation on health care costs is higher than the normal consumer price index – almost 70 percent higher,” says Megan Gorman, managing partner at Chequers Financial Management in San Francisco. Equities are necessary for keeping pace with inflation, and “if you stay in cash, you’re really eroding your principal to handle health costs.”

One thing people often don’t realize is that HSA funds can be tapped for other expenses in retirement. “You can take money out of an HSA after age 65 for non-medical expenses without a penalty,” says Tony D’Amico, CEO and senior wealth advisor at Fidato Wealth in Strongsville, Ohio. You still pay income tax on the distribution, but in essence, “your HSA ends up being like an IRA.”

Gorman says it may be more efficient to fund an HSA versus an IRA, to some degree. She points to the higher annual contribution limit allowed for family HSA coverage: $6,900, compared to the $5,500 allowed for traditional and Roth IRAs. There is one thing you have to watch out for, however. “If you take funds out prior to age 65 for non-medical expenses, you’ll owe income tax and a 20 percent penalty on the withdrawal,” Gorman says.

Consider your timeline for the money. If you’re ready to trade some of your cash holdings for stocks, mutual funds, exchange-traded funds or other investments, think about the timing. “It’s important to consider your short, medium and long-term needs from the account and your risk tolerance before choosing specific investments,” Herd says. Any money that you think you may need in the next few months to a year should be left in cash. The rest can be invested according to your risk and diversification preferences.

Market timing is another consideration when investing in and withdrawing from an HSA, says Joe Heider, president of Cirrus Wealth Management in Cleveland. “It’s a mistake to put in equity when the market is hitting all-time highs and have to pull it out when the market is down.”

D’Amico says investors should think about specific uses for HSA funds when choosing investments. For example, you may plan to use HSA money to pay for Medicare premiums. Or, you may be earmarking it for long-term care. “Estimating your time horizon for your HSA should center around health considerations, as well as when you intend to use those funds.”

Like any investment, review the fees involved, including the expense ratio and the portfolio and management fees. Baltzell says that’s especially important if you’re investing in low-return products. “If you’re in a less risky bond portfolio and fees are high, you’re losing money.”

Finally, Jalinski says to consider how a fund manages risk in downturns. He says investors typically look at the three, five and 10-year averages but in a strong market, it helps to take a slightly broader view of performance. Reviewing how an investment behaved in a downturn, such as the most recent one from 2007 to 2009 can “help fight the false sense of security that a bull market can provide.”