Is a heating pad treated differently than a chemical hand warmer?

No restriction either way — an electric heating pad is an ordinary appliance, and disposable chemical hand/body warmers are also allowed.

Heating Pad

Electric heating pads are allowed in carry-on and checked bags without restriction.

Carry-on

Allowed

Checked

Allowed

Allowed. An electric heating pad is a corded household appliance with no restriction.

Allowed. No restriction in checked baggage.

A disposable, single-use chemical heat pack (not electric) is also allowed — see the hand warmers entry for that type.

Is a heating pad treated differently than a chemical hand warmer?: No restriction either way — an electric heating pad is an ordinary appliance, and disposable chemical hand/body warmers are also allowed.