"Not every high-deductible plan makes people eligible for an HSA," Ramthun said. The confusion about high-deductible plans can make it harder for people to embrace HSAs, he said.
That's unfortunate because HSAs can be a powerful retirement savings vehicle. Fidelity estimates that a 65-year-old couple retiring in 2016 would need roughly $260,000 to cover health-care costs during retirement. So if you have 22 years of retirement, that's roughly $985 per month. A well-funded HSA can cover that cost completely tax-free.
And if you're healthy enough to not have many health care costs in retirement, you can withdraw the money from your HSA without penalty and use it for anything you want when you are age 65 or older. However, you will pay income taxes on withdrawals if you don't use it for health care.
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Because of the triple-tax advantages, workers may need to revamp their retirement savings strategy. Jeanne Thompson, a senior vice president at Fidelity, recommends that people contribute to their retirement plans enough to receive matching contributions from their employer and then fund their HSAs because they have more tax advantages.
Keep in mind that HSAs have much lower contribution rates than workplace retirement plans. In 2017, you (and your employer) can contribute up to $3,400 to an HSA for individuals and $6,750 for families. Account holders age 55 and older can contribute an extra $1,000. For 401(k)s and other retirement plans, you can contribute up to $18,000 this year and $6,000 more if you are age 50 and older.
HSAs don't seem to crowd out 401(k) contributions and may actually be increasing overall retirement savings among workers.
Employees using both a 401(k) and HSA had a higher savings rate, 10.6 percent of their 2016 salary, compared with those saving in just a 401(k), which was 8.2 percent of salary, according to a recent analysis of the employee benefit programs Fidelity manages for more than 23,000 businesses. Fidelity found that 88 percent of people who opened an HSA maintained or increased their 401(k) savings after they enrolled in an HSA.
"It's almost like savings begets savings," Thompson said.