Most insulated food thermoses are designed to keep food hot for 5 to 10 hours, depending on the brand, size, and how you pack them. For school lunches, I look for a container that keeps food hot from when I pack it in the morning until my kids are ready to eat. Below, I’ve compared popular thermos containers and shared what makes the biggest difference in keeping food hot.
How long does a thermos keep food hot?
If you pack lunch at 7 a.m. and your child eats at noon, you need a thermos that can keep food hot for at least 5 hours. Some containers are rated for longer than others, so it’s worth checking before you buy. Here’s how popular brands compare.
| Brand | Hours Hot (advertised) | Approx. Price |
|---|---|---|
| Thermoflask | up to 7 | $25-$30 |
| Hydrapeak | up to 10 | $20 |
| Funtainer | up to 6 | $20 |
| Lunchbots | up to 6 | $30 |
| YETI | up to 8 | $50 |
| Omiebox | up to 5 | $45 |
| Amazon Basics Thermos | up to 8 | $14 |
How to keep food hot in a thermos for lunch
The two things that make the biggest difference are heating the food thoroughly and preheating the thermos before filling it. A cold container immediately pulls heat from the food, which means lunch cools down faster. I show you exactly how to preheat a thermos so the food stays hot longer.
Is it safe to keep food warm in a thermos?
Yes, you can safely pack hot food in a thermos, but keeping it warm and keeping it at a food-safe temperature aren’t the same thing. Hot perishable foods should stay at 140F or above. How long that lasts depends on the thermos, how hot the food was when you packed it, and how long it sits before lunch.
If you’re unsure whether your container keeps food hot enough, test it at home with a food thermometer at the time your child would normally eat.
How to Pack Hot and Cold Lunch Together
When choosing a thermos for school lunches, I look at three things: how long it keeps food hot, how much food it holds, and whether my kids can open it without help.
Another option for younger kids is the OmieBox, an all-in-one lunchbox with a built-in thermos that keeps food hot for up to 4 hours. I like that you can pack a hot main dish and cold sides in separate compartments without needing multiple containers.
Best Hot Food Thermoses
When choosing a thermos for school lunches, I look at three things: how long it keeps food hot, how much food it holds, and whether my kids can open it without help. I’ve tested many containers over the years, and you can see my favorite thermos containers for kids to find one that works for your child’s age and appetite.
Still wondering what to pack?
Download my Printable Lunchbox Builder to turn the ingredients you already have into lunch ideas in minutes, or browse hundreds more kid-approved lunch recipes here.
Sunetra says
Should I still use cold packs inside the lunch box while packing a hot lunch in a thermos?
MOMables says
Yes. a thermos keeps the temperature hot inside. the icepacks are for the rest of the food (when needed)
Erica munden says
Hi
I would like to know if any one has any suggestions on a food box or something to keep food hot, I,m going to do a food service driving round before I buy a jiffy van,
Ericaxx
MOMables says
I’m sorry, I don’t know. perhaps you can go on amazon and look for those big delivery bags that the pizza people use?
Kelly says
The catering company my daughter worked for used regular coolers like igloo. They heated the food in foil serving dishes and stacked them in the coolers.
Jorge says
Hello,
Does anybody has any experience using Mr. Or Ms Bento container kits?
MOMables says
No, I’m sorry. I prefer thermos containers or those made of stainless steel specifically for hot items
Ann Marie says
This may be a silly question, but his do you heat up the thermos? Is it microwave safe? The one I own has a metal interior.
Thanks
Ann Marie says
I did see your post on how to heat up the thermos, thanks!!
Nikki says
I am looking for a good container for my husband that will hold plenty of food for him and keep it warm for quite a while. I was checking out the Stanley you shared about above and while reading reviews some people was saying that this was great at first and then lost its seal and wasn’t keeping the food hot for long, after only a month or so. I was wondering if you have experienced this at all? Thanks soo much, just found your site today (from 100 days of real food) and already love it!
http://www.amazon.com/Stanley-17oz-Classic-Vacuum-Black/dp/B0019D7AGE/ref=lh_ni_t?ie=UTF8&psc=1&smid=ATVPDKIKX0DER
MOMables says
Hi Nikki! Thanks for visiting us! I love that Stanley thermos. That’s the one my husband takes to work. The seal might of come off for other people if they wash and dry the lid in the dishwasher. I only wash the bottom of it, the top by hand. The “seal” is a rubber gasket/band and can come loose with high temperatures. I’ve had mine for over a year with 2-3x week use and no issues. :)
brittany says
Why no onions??
MOMables says
they tend to stink the lunchbox, often make other foods soggy..etc.
Amie says
You have mentioned heating up the thermos but most are stainless steel so can’t go in the microwave. How do you recommend heating them up properly?
MOMables says
Amie, check this post.
Kimberly says
Thank you for this informative post! I love your site, and your newsletters. It is nice to follow you on Pinterest, as well, to see specific articles like this one on mornings when it seems like I need the advice the most! Your efforts for this experiment will help many, many Moms out there to pack great hot lunches! I do have one question – when I pack a Thermos with hot lunch for my kids I often don’t know what else to include with the entree. I am so used to packing items with a cold pack that I don’t know what accoutrements I can send with a hot Thermos full of, for example, ravioli with sauce. What items do you suggest?
MOMables says
Kimberly, pack anything else you would normally send. the thermos containers don’t absorb heat or cold from the outside. I send fruit, veggies and dip, some of the bars in our recipe section… a thermos is just a container… send the same items you would normally pack in another container.
Kimberly says
Thanks for your response! Do you still use a cold pack to keep the other foods chilled?
MaryB says
I use a Packit for my kid’s lunches and we put the Thermos inside with the rest of the food. The food inside the Thermos stays hot just fine. We use the Funtainers.
Rashelle says
So thorough, thank you for the great advice.
Debbie W says
Excellent advice. I have the 10 oz. Thermos brand stainless containers plus another bigger stainless container that I don’t remember the name of. I always preheated the container by pouring boiling water in it. After dumping the hot water, I then added the hot soup. My daughter had no problems at all when she was young with this. Especially since she’s my soup kid. From when she was tiny to today, at 21, she will still eat soup before most other things.