The requirement is not retroactive, so at-home tests purchased before January 15 do not qualify for reimbursement.
The move, which President Joe Biden announced last month, comes as Americans desperately seek testing amid a surge of the Omicron variant. Finding at-home tests is proving challenging in many parts of the country, even as retailers limit the number that can be purchased by one customer.
"The success of the Biden administration's requirement that insurers pay for at-home Covid tests will depend, of course, on being able to snag those valuable tests to begin with," tweeted Larry Levitt, executive vice president for health policy at the Kaiser Family Foundation, on Monday.
The administration also is purchasing 500 million at-home tests to be distributed for free. The first tests will start arriving for distribution "early next week," the White House said Monday.
It is setting up a website and hotline where Americans can request the tests. More details should be available later this week, the White House said.
Health insurers will implement the guidance as quickly as possible and seek to limit consumers' confusion and challenges, Matt Eyles, CEO of America's Health Insurance Plans, known as AHIP, said in a statement.
"While there will likely be some hiccups in early days, we will work with the administration to swiftly address issues as they arise," Eyles said, while reinforcing the importance of vaccines to fight the coronavirus.
Another major insurer industry group noted the short deadline to launch the program.
"We are concerned that the policy does not solve for the limited supply of tests in the country and could cause additional consumer friction as insurers stand up a program in just four days' time," said Kim Keck, CEO of the Blue Cross Blue Shield Association.
Medicaid and the Children's Health Insurance Program, known as CHIP, already cover at-home tests with no cost-sharing. Medicare covers at no charge Covid-19 testing done in a lab when ordered by a medical professional. Those enrolled in Medicare Advantage plans should check with their insurers to see if at-home tests will be paid for, HHS said.