Yes, a cooler works fine for keeping food warm.

With a little prep. The trick is preheating the cooler itself — pour in hot tap water, close the lid for 10 minutes, dump it out, then line the bottom with towels. Put your hot food in (in covered dishes), fill any empty space with more towels or crumpled newspaper, and close the lid tight. It holds temp for a couple hours easily.

You can also toss in a few hot water bottles or bricks heated in the oven to extend the time. Just don’t use this for food that needs to stay above 140°F for more than two hours — a good insulated cooler will keep things hot, but it’s not a slow cooker. Use a thermometer if you’re nervous.

It’s a cheap alternative to a hot box, and it works better than you’d expect.