For hot lunches, buy a jar, not a bag

For hot lunches, the answer is a vacuum-insulated food jar like the Thermos Stainless King — not a soft lunch bag and not a plug-in electric box.

Soft lunch bags are passive insulation. They’ll keep a chilled sandwich cold-ish, but they don’t add heat. Anything hot goes in at 9am and by noon it’s lukewarm. The only thing that actually traps heat is a double-walled vacuum container.

The Thermos