Short answer: Grandfathered plans are exempt from several ACA consumer protections. They do not have to cover preventive care at no cost, guarantee your right to appeal a coverage decision, protect your choice of doctors and emergency-room access, or follow rate review. They must still honor others, like no lifetime limits, coverage of adult children to age 26, and a Summary of Benefits and Coverage.
A grandfathered plan is one that existed on March 23, 2010 and has not made major changes that cut benefits or raise costs. If you have a grandfathered plan, you may not get some rights and protections that other plans offer under the Affordable Care Act, and your insurer must tell you the plan is grandfathered.
By regulation, being a grandfathered health plan means your plan may not include certain consumer protections of the Affordable Care Act that apply to other plans, for example, the requirement for the provision of preventive health services without any cost sharing. Grandfathered plans also do not have to provide the internal and external appeals process or protect your choice of doctors. They do, however, still have to end lifetime and yearly dollar limits, cover adult children to age 26, and provide a Summary of Benefits and Coverage. If these gaps matter to you, you can switch to a Marketplace plan during Open Enrollment, or through a Special Enrollment Period when the grandfathered plan ends.