Best Electric Lunch Box for an Office Without a Microwave: 8 Plug-In Warmers Compared

If your office has no microwave, the best electric lunch box is a plug-in heated model with roughly 80W to 100W of heating, a capacity of about 1.5 to 1.8 liters and a household-voltage setting, and the DUPASU 1.8L at 100W is the best all-round fit among the corded listings while staying in the middle of the price range. One cordless, rechargeable model sits in a category of its own and is worth considering if the desk has no spare outlet. Before you buy any of them, plan on 30 to 45 minutes of warm-up time, and plan your food-safety habits around it.

Most of the listings below are marketed as much to truck drivers and road workers as to office staff, which is why their titles list 12V, 24V and 110V. For a desk, only the wall-power mode matters. The rest of the guide shows how to read those labels, how to estimate heating time, and what a safe routine looks like.

The short list, before the details

DUPASU Electric Lunch Box Food Warmer, 1.8L Heated Lunch Box for Adults | 100W Fast Heating, Portable Food Heater for Car, Truck, Office, Work, Travel, Construction Site, Gifts, 12/24V/110-230V

Included for 'Best Electric Lunch Box for an Office Without a Microwave: 8 Plug-In Warmers Compared' as a representative product in this roundup; selection reflects the product set returned for this topic.

View on Amazon →

SOHIDA 1.5L Electric Lunch Box Food Heater, 80W Heated Lunch Box (Green) | Portable Warmer for Car/Truck/Work, 12V/24V/110V Lonchera Eléctrica Portátil, Suitable for Ideal Driver/Work/Gift

Included for 'Best Electric Lunch Box for an Office Without a Microwave: 8 Plug-In Warmers Compared' as a representative product in this roundup; selection reflects the product set returned for this topic.

View on Amazon →

1.8L Heated Lunch Box for Men, Portable Food Warmer for Car/Truck/Office | Sohida 80W Electric Lunch Box for Adults: Leak-Proof and Dishwasher-Safe, 12V/24V/110V Lonchera Eléctrica Portátil for Worker

Included for 'Best Electric Lunch Box for an Office Without a Microwave: 8 Plug-In Warmers Compared' as a representative product in this roundup; selection reflects the product set returned for this topic.

View on Amazon →

TRAVELISIMO Electric Lunch Box for Adults 100W Heated Lunch Box For Men 1.5L Stainless Steel Portable Food Warmer, 12/24/110V for Travel & Work, Loncheras Electricas Para Calentar almuerzo

Included for 'Best Electric Lunch Box for an Office Without a Microwave: 8 Plug-In Warmers Compared' as a representative product in this roundup; selection reflects the product set returned for this topic.

View on Amazon →

Buddew Electric Heated Lunch Box, 100W Fast Heating, 1.5L Food-Grade 304 Stainless Steel, 12V/24V/110V Portable Food Warmer for Car Truck Office Adults, Lonchera Electrica Portatil (Green)

Included for 'Best Electric Lunch Box for an Office Without a Microwave: 8 Plug-In Warmers Compared' as a representative product in this roundup; selection reflects the product set returned for this topic.

View on Amazon →

LISHZEN Electric Lunch Box for Adults, 2.8L Double Layer Heated LunchBox | 100W Fast Heating Food Heater Warmer for Home Office Car Truck, Extra Large Lonchera Electrica Portátil 12/24V/110-230V,Black

Included for 'Best Electric Lunch Box for an Office Without a Microwave: 8 Plug-In Warmers Compared' as a representative product in this roundup; selection reflects the product set returned for this topic.

View on Amazon →

Electric Lunch Box Food Heater, 3 in 1 Ultra Quick Heated Lunch Boxes for Adults, 12V/24V/110V Portable Food Warmer for Car/Truck/Office With Fork Spoon and Insulated Carry Bag, White Elephant Gifts

Included for 'Best Electric Lunch Box for an Office Without a Microwave: 8 Plug-In Warmers Compared' as a representative product in this roundup; selection reflects the product set returned for this topic.

View on Amazon →

Cordless Electric Heated Lunch Box, 1.5L - 6.3 Cups 100W Rechargeable Smart Self-Heating Food Warmer with Removable Divider, Spoon, Fork, BPA Free, Portable Lunchbox for Car Travel Office Lake Green

Included for 'Best Electric Lunch Box for an Office Without a Microwave: 8 Plug-In Warmers Compared' as a representative product in this roundup; selection reflects the product set returned for this topic.

View on Amazon →

Tiers are relative to this set of eight. The cordless model is a different technology from the other seven, so its tier does not compare like with like.

Reading the voltage line like a purchasing manager

Seven of the eight listings advertise multi-voltage operation. Here is what each number means for an office worker:

• 12V: the nominal supply from a car’s cigarette-lighter socket. Irrelevant at a desk.
• 24V: typical of many trucks. Also irrelevant at a desk.
• 110V: the nominal household wall voltage in the US, as many listings describe it. This is the mode you will use. The unit should come with a wall cord or adapter; confirm in the listing which cord is included, because some products ship with only a car cord.
• 110-230V: appears in the DUPASU and LISHZEN titles and suggests a wider range for travelers. It does not change anything for a US desk.

Pay attention to cord and plug details, because using the wrong cord on the wrong supply is the most common way a multi-voltage device gets damaged. Follow the manufacturer’s manual, and if any listing does not show certification marks you recognize, such as a UL or ETL mark, ask the seller. The titles in this set do not mention safety certifications, so we cannot say whether any of these carry them.

Our eight picks

Each entry below sticks to what the title says. Anything not in the title, such as heating element design, cord length, certifications or battery runtime, is marked as something to confirm on the product page.

DUPASU Electric Lunch Box Food Warmer, 1.8L, 100W

The DUPASU title is a long list of claims: 1.8 liters, 100W fast heating, portable for car, truck, office, work, travel and construction site, gift-ready, and rated for 12V, 24V and 110-230V. It is the best fit for the reader who wants a roomy container and a 100W rating, the top wattage in this set, without stepping up to the pricier listings. At 1.8 liters, the capacity is enough for a serving of pasta plus a side or a generous bowl of rice and curry.

Wattage matters, but it is only half the story. A 100W element heats faster than an 80W one only if the heat reaches the food efficiently. We cannot tell from the title whether the container is stainless steel, aluminum or plastic, whether the lid seals, or how the element is arranged. Those details determine whether the bottom layer scorches while the top stays lukewarm. Look for photos of the inside and for buyer comments on uneven heating.

The multi-voltage claim is worth a close read of the included cords. A 100W draw at 12V is roughly 8 amps, which is an estimate from simple arithmetic, so it is a heavier load on a car socket than it sounds. At a desk, you will use the wall mode, where the draw works out to under one amp at household voltage (100W divided by 110V is about 0.9 amps, an estimate).

Pros

• 1.8L capacity and 100W heating on paper
• Voltage range extends to 230V for travel
• Mid-range price tier for a full-size unit

Cons

• Container material is not stated in the title
• Marketed heavily for vehicles and sites, so office-specific cord details need checking
• Larger footprint on a small desk

Who it’s for: an office worker who wants a large container and fast wattage and does not need a stainless-steel-only build.

SOHIDA 1.5L Electric Lunch Box Food Heater, 80W (Green)

This is one of the least expensive units in the set, and the title is specific: 1.5 liters, 80W, green finish, 12V, 24V and 110V. It positions itself for car, truck and work use. The 80W figure is the lowest in the set among the corded models with a stated wattage, so expect slower heating than the 100W units. Based on the arithmetic in our heating guide below, that could mean 30 to 40 minutes for a modest portion rather than 25 to 35, which is an estimate and not a measurement.

The 1.5L size is plenty for a single-person portion of soup, stew or a rice bowl, and it will fit more comfortably in a bag or a drawer than the 1.8L and 2.8L units. If you eat small or you normally pack a side separately, the capacity will not be a limitation. If you tend to bring a huge portion, you will find the container fills quickly.

What the title does not tell you is the material, the lid design or whether the heating base can sit on a desk without marking it. Check photos for rubber feet and for how the cord attaches. This listing is the cheapest way into the category, but being cheap is not the same as being the safest choice for every kitchen, so read the manual for the cord-care and cleaning instructions.

Pros

• One of the lowest listing prices in the set
• Compact 1.5L size
• Lowest wattage means lower power draw at the outlet (about 0.7 amps at 110V, an estimate)

Cons

• 80W will probably heat more slowly than 100W models
• Container material not given in the title
• Small capacity if you pack large portions

Who it’s for: someone who packs a single modest meal and wants the cheapest corded entry point.

SOHIDA 1.8L Heated Lunch Box for Men, 80W, Leak-Proof and Dishwasher-Safe

The same brand’s larger sibling shares the 80W rating but adds capacity (1.8 liters) and two features in the title: leak-proof and dishwasher-safe. For an office without a microwave, the leak-proof claim matters most on the commute, when a loose lid can ruin a bag. The dishwasher-safe claim matters on the back end, when the cleaning routine decides whether you keep using the thing. Do not assume that claim covers the heating base. No manufacturer would normally describe a plugged-in heating element as dishwasher-safe, so confirm which part, almost certainly the removable food container, can go in the machine.

Because the wattage is the same as the 1.5L version but the container is larger, heating a full 1.8L container will take longer than heating a half-full 1.5L one. That is simple physics: more food needs more energy. If you fill the larger unit to the brim, our estimate pushes toward the upper end of the 30 to 45 minute window, possibly beyond it. Stir halfway through, and use a thermometer if you are unsure whether the center has reached a safe temperature.

The title says “for Men,” which is marketing language and does not change the product. Ignore it. What is more useful is that the price tier is only slightly above the 1.5L model, so you are paying a step up for more space and the washability. Neither the capacity nor the cleaning claim changes the wattage, so the larger size is the thing to weigh against your patience at lunchtime.

Pros

• Larger 1.8L capacity at 80W
• Leak-proof and dishwasher-safe per the title (check which parts)
• Mid-range price tier

Cons

• 80W is slow for a large portion
• Dishwasher claim probably applies to the container only
• Near-duplicate of the 1.5L listing from the same brand, so compare the details carefully

Who it’s for: an office worker who wants more room and easy cleanup and is patient about warm-up time.

TRAVELISIMO Electric Lunch Box for Adults, 100W, 1.5L Stainless Steel

The TRAVELISIMO listing is the second most expensive in the set, and the title gives you three concrete reasons: 100W, 1.5 liters, and stainless steel. Stainless steel is a common choice for the food container because it does not hold odors the way some plastics do and is generally straightforward to wash. The title does not say which grade or whether the steel covers only the inner container, so check the product page.

It lists 12V, 24V and 110V and says it is for travel and work, with Spanish keywords in the title for the same product type. In the context of an office, what you are buying is a metal-bodied 100W container with a mid-sized capacity. If the lid and body are well built, it should survive daily commuting better than a thinner plastic design. That is a hypothesis, not something we have verified, and the premium tier should come with better materials in return, not just better branding.

Compared with the Buddew unit, which has a similar spec list at a lower price, the main reasons to choose this one would be differences in finish, lid design or cord details that you can see in the photos. If those details are not obvious, the cheaper stainless listing may offer similar value. Ask whether the listing’s pictures show a locking lid and a removable container.

Pros

• Stainless steel build named in the title
• 100W heating and 1.5L capacity
• Voltage options for home, office and vehicle use

Cons

• Premium price tier for a spec list similar to cheaper models
• Title does not specify whether the whole container is steel
• No cutlery or bag mentioned in the title

Who it’s for: buyers who prioritize a metal container and are willing to pay more, provided the build quality shows in the photos.

Buddew Electric Heated Lunch Box, 100W, 1.5L 304 Stainless Steel

Buddew’s title is the most material-specific in the set: food-grade 304 stainless steel, 1.5 liters, 100W fast heating, 12V, 24V and 110V. The “304” refers to a common stainless steel grade used in food contact applications, and the “food-grade” wording is the seller’s. It is a useful signal, but we have not verified it, and a listing title does not substitute for the documentation you would need to confirm material composition.

For an office, the combination of 100W and 1.5L is a sensible one. The capacity is enough for a single serving, and the wattage should bring cold leftovers up to temperature in the 30-to-40-minute range under our assumptions. It sits in the budget tier, which makes it the cheapest listing in this set with both 100W and stainless steel in the title. That makes it a natural comparison point for the more expensive TRAVELISIMO.

The main questions it leaves open are lid design and cord length. A short cord can force you to use an extension, and extension cords and power strips are best avoided for heating appliances unless the manual explicitly allows them. Look at the product photos for the cord, and consider where your desk outlet is before ordering. It is also worth reading buyer comments for any mention of the lid, since a 304 stainless body only helps if the lid closes firmly and the gasket can be removed for washing.

Pros

• 304 stainless steel and 100W at a budget tier price
• 1.5L is a practical single-serving size
• Multi-voltage listing

Cons

• Cord length and lid details are not in the title
• No cutlery or carry bag named
• The “food-grade” label is a seller claim

Who it’s for: a cost-conscious office worker who wants stainless steel and 100W without paying the premium tier.

LISHZEN Electric Lunch Box, 2.8L Double Layer, 100W

At 2.8 liters and double layered, this is the biggest unit in the set by a wide margin. The “double layer” wording suggests two stacked compartments, which is useful if you want to keep a main and a side separate, but the title does not explain how the heating reaches each layer. Check the photos and the description carefully before assuming both layers heat at the same rate.

The 100W rating is the same as the smaller units, which is the main catch. Heating nearly twice the food with the same power draw takes longer. By the same simple energy arithmetic as in our heating section, a fully loaded 2.8L unit could need considerably more than 45 minutes, a figure that is an estimate and depends on how you pack it. If your meal is cold from the fridge and you stack two portions, plan to plug in well before lunch, and stir where you can.

The title lists 12V, 24V and 110-230V, and includes “home office car truck” use. The unit is bulky, so it is a better fit for a desk with space than for a shared cubicle. It is also a poor choice if your bag is small. For a large appetite, a shared lunch, or a separate soup-and-solid arrangement, it is the only option here that offers that much room. Weigh that against the realities of a shared office: a big unit in a communal area takes up space, and it is a good idea to label it so nobody mistakes it for a spare appliance.

Pros

• 2.8L capacity, the largest in the set
• Double layer design for separate foods
• Mid-range price tier

Cons

• 100W for a much larger volume means slower heating
• Bulky to carry and store
• Unclear from the title how each layer heats

Who it’s for: big eaters or people who want a main and a side kept apart, with a desk that has room for a large container.

Herrfilk Electric Lunch Box Food Heater, 3 in 1, with Fork, Spoon and Insulated Bag

The Herrfilk title is the only one in the set that promises accessories: a fork, a spoon and an insulated carry bag. It also lists 12V, 24V and 110V and calls itself an “ultra quick” heater. What the title leaves out is the wattage and the capacity, two numbers that matter more than the accessories. Look at the full listing for them. If wattage is missing from the description, ask the seller before buying, because the wattage determines how fast the unit works and how large a load it puts on the outlet.

The “3 in 1” wording most likely refers to the three-way power options (12V, 24V and 110V), but this is an inference, not a statement from the title. The insulated bag is a real convenience, because you can carry the food container without a separate bag. The cutlery is a smaller convenience, since many offices have forks, and metal cutlery can scratch some inner coatings.

The listing price is the second-lowest in the set, so you are getting a lot of extras for the money. The trade-off is information: with unspecified wattage and size, you are less able to predict heating time than with the other listings. Without a wattage figure you also cannot work out the outlet load or compare it with the 80W and 100W models. A sensible approach is to open the product page, look for the power label in the photos, and message the seller if it still is not shown. If the answer is vague, one of the better-documented models above is the safer buy.

Pros

• Includes fork, spoon and insulated carry bag per the title
• Budget price tier
• 12V, 24V and 110V options

Cons

• No wattage or capacity in the title
• Container material not stated
• Extras may matter less than heating performance

Who it’s for: a buyer who wants a bag and cutlery included and will check the full listing for the missing specs.

EDCREATY Cordless Electric Heated Lunch Box, 1.5L, 100W Rechargeable

This listing is the odd one out and the only one that does not depend on a nearby outlet. It is described as cordless, rechargeable and self-heating, with a 1.5 liter capacity (6.3 cups), a removable divider, a spoon, a fork and BPA-free construction. For an office with no free outlet at your seat, or for a workday that moves around, a battery-powered unit solves a real problem. It is also the most expensive listing here by a clear margin.

The same arithmetic that applies to the corded units applies here, and the battery is the bottleneck. By our estimate in the heating section, bringing a 400 gram portion from fridge-cold to steaming needs on the order of 45 watt-hours delivered into the box. Whether the battery can supply that for a full load, and how many days it holds that charge, is not in the title. Look for a watt-hour or milliamp-hour figure and for user comments on the number of heating cycles per charge.

Battery products also bring their own cautions. Charge only with the supplied charger, do not charge it unattended on a soft surface or near flammables, and stop using it if it swells, smells or overheats. Follow the manual, and do not take it apart. A lithium battery that is damaged can be a fire risk, and that is a good reason to read the manufacturer’s instructions closely.

Pros

• No outlet required once charged
• Removable divider, spoon and fork included per the title
• BPA free per the title

Cons

• Highest listing price in the set
• Battery capacity and runtime are not in the title
• Battery charging adds its own safety considerations

Who it’s for: someone whose workplace seating has no convenient outlet and who accepts the extra cost and the battery care.

How we picked these

The Editorial team compiled this list from published specifications, manufacturer documentation and buyer reviews. Nobody on the team used or measured these units, so none of the heating times below come from a thermometer or a stopwatch. They come from a simple energy calculation with assumptions stated in the next section.

We asked four questions of each listing. Does the title tell you the wattage and capacity? Does it show a material for the food container? Is there any indication of how the unit is powered at a desk, as opposed to in a vehicle? And are there accessories that change how you would use it day to day? Products that left several of these blank were not removed, but they are flagged, and their descriptions are more cautious.

The set also contains two near-duplicates, the SOHIDA 1.5L and 1.8L, which share a brand, wattage and voltage list but differ in capacity and in the extra features named in the title. The cordless EDCREATY is a separate type and should be judged against a different checklist.

A heating-time estimate you can adjust

You can estimate warm-up time with a few steps. These are the assumptions, and you can change them for your own meals.

1. Portion: 400 grams of leftover pasta or rice and sauce, straight from a 4°C (about 40°F) fridge.
2. Target: 74°C (165°F), the temperature food safety agencies such as the USDA recommend for reheated leftovers.
3. Specific heat: about 3.5 joules per gram per degree Celsius for a moist, mixed meal. This is a rough figure.
4. Energy needed: 400 g × 3.5 × 70°C change = about 98,000 joules, or roughly 27 watt-hours.
5. Efficiency: assume 60 percent of the electrical power ends up in the food, with the rest warming the container, lid and surrounding air. That makes the electrical input about 45 watt-hours.
6. Time: 45 Wh at 100W is about 27 minutes. At 80W it is about 34 minutes.

In practice, add margin for a cold container, a loose lid or dense food. A realistic planning range is 30 to 45 minutes, and a full 2.8L unit could take longer. Stir once halfway. Check the middle of the food with a clean utensil or a food thermometer, since a hot rim can hide a cold center.

The electricity cost is tiny. At 45 watt-hours and an assumed rate of 17 cents per kilowatt-hour, a heating cycle costs less than one cent. The expense of these devices is the purchase price, not the power.

The 12V arithmetic for the commute

If you also plan to use the unit in a vehicle, watch the current. Power equals voltage times current, so 100W at 12V is about 8.3 amps, and 80W is about 6.7 amps. Those are estimates. Many vehicle sockets are fused somewhere between 10 and 20 amps, but the figure varies, so check the owner’s manual. Running a heater on a parked car with the engine off can drain the battery. For an office-only buyer this does not matter; for a delivery driver it is the main safety consideration.

Food safety at the desk

The point of a heated lunch box is to warm food that has been kept cold. It is not a way to keep food warm for hours. Keep the container in a fridge or a cooler bag with an ice pack until you are ready to heat it. Heat it until it is steaming throughout, eat it, and do not let it sit in a lukewarm box. Agencies such as the USDA advise that perishable food should not remain in the temperature danger zone of roughly 40 to 140 degrees Fahrenheit for more than two hours in total, or one hour if the room is above 90 degrees.

Avoid putting raw meat or raw eggs in a lunch box and expecting the heater to cook them safely. These devices are intended to reheat cooked food. If you batch cook on weekends, our guide to the best electric pressure cooker covers a tool that makes the cooking side easier, and then the lunch box handles the reheating.

If you have a health condition that makes you more sensitive to foodborne illness, or you are pregnant, ask your doctor about specific reheating guidance for your situation.

Electrical safety and office etiquette

• Ask first. Many workplaces have policies on personal heating appliances. Check with facilities or your manager.
• Plug straight into the wall. Avoid extension cords and crowded power strips unless the manual allows them, since heating appliances draw a steady load.
• Never immerse the base or cord in water. Wipe it with a damp cloth when it is unplugged and cool.
• Protect the cord. Keep it from sharp edges, drawers, chair wheels and anywhere people walk. Stop using the unit if the cord or plug is damaged.
• Do not cover vents or place the unit on paper, fabric or other flammable surfaces while it is heating.
• Do not leave it running unattended for long periods, and unplug it when done.
• Stop at the first sign of trouble. A warm outlet, a burning smell, sparks or a tripped breaker mean you should unplug it and ask a qualified electrician or your building’s facilities team.

Follow the manufacturer’s manual for any specifics, including whether any part is dishwasher safe and how to clean the base.

What to look for in an electric lunch box

Wattage

Wattage is the rate at which electricity becomes heat. Between 80W and 100W, the difference in warm-up time is modest, about 7 minutes in our worked example. A bigger factor is how well the container holds the heat in.

Capacity

Capacity ranges from 1.5 to 2.8 liters in this set. A liter of dense food weighs roughly a kilogram, so a container filled to the brim would hold several pounds, far more than a normal lunch. Most people fill a unit to a third or a half, which means a 1.5L box already handles a 400 gram portion with room for stirring. A bigger container is not better if you never fill it, because empty space and extra metal take heat that should be going into the food.

Material and cleaning

Stainless steel is easy to wash and holds up to scrubbing; plastic parts should be BPA-free if that matters to you, and a removable container is easier to clean than a fixed one. Look for a lid gasket you can remove and dry.

Cord and plug

A cord long enough to reach the outlet without stretching, a firmly fitting plug and strain relief at the entry point are all signs of a well-made appliance. They are rarely in titles, so scan the photos.

Mistakes buyers make

1. Assuming the vehicle cord is the wall cord. Confirm the cord that comes in the box.
2. Loading the container with frozen food. These units are meant for reheating chilled, cooked food. Frozen blocks heat unevenly and slowly.
3. Sealing the lid so tightly that steam has nowhere to go, if the manual says to vent. Read the lid instructions.
4. Letting food sit warm for hours. It is a food-safety problem.
5. Using extension cords. Heating appliances are a poor match for long, thin cords.
6. Buying on wattage alone. A well-insulated 80W unit can match a leaky 100W one.

Verdict

For most office workers, the DUPASU 1.8L at 100W offers the best balance of capacity, wattage and price tier among the corded models. The Buddew 1.5L is the better pick if you want 304 stainless steel at a budget tier price. The SOHIDA 1.5L is the cheapest way in, provided you accept slower heating. If you have no free outlet and a decent budget, the EDCREATY cordless unit is the only real option, though you should confirm battery details first. Whichever you choose, treat it as a reheater, plan on 30 to 45 minutes, and follow the manual and your workplace’s rules.

Related guides

• Flat Bottom Carbon Steel Wok For Induction
• Belgian Waffle Maker With Removable Plates
• Electric Griddle For Pancakes And Bacon

Frequently asked questions

Can I use an electric lunch box at my desk?

Usually yes on the electrical side, because the listings here list 110V operation and include a standard plug in their descriptions, but your workplace may have its own rules about personal heating appliances. Ask facilities or your manager before plugging in. Use a wall outlet if you can, keep the cord out of walkways, and never leave it running unattended for long periods. If an outlet feels warm or trips a breaker, stop and report it.

How long does an electric lunch box take to heat food?

Expect roughly 30 to 45 minutes for a cold, fridge-temperature portion of around 400 grams in an 80W to 100W unit. That is an estimate from a simple energy calculation with stated assumptions, not a measured result, and it shifts with portion size, how dense the food is and how well the lid seals. Stirring once halfway helps even heating. Check the temperature before eating.

Is it safe to leave food in a heated lunch box all morning?

No. Food safety guidance from agencies such as the USDA says perishable food should not sit in the temperature danger zone, roughly 40 to 140 degrees Fahrenheit, for more than two hours in total. Keep the food cold until you plug the unit in, heat it so that it is steaming hot throughout, then eat it. A lunch box warms food; it is not a slow cooker or a safe holding device.

What does 12V, 24V and 110V mean on the listing?

These are the supply voltages the unit says it can run from. 12V suits a car cigarette-lighter socket, 24V is for many trucks, and 110V is the nominal household wall voltage in the US. For an office you will use the wall setting or cord. Some listings add 230V for other regions. Always use the correct cord for the supply, and read the manual before you plug anything in.

How do I clean an electric lunch box safely?

Unplug it and let it cool first. Never immerse the heating base or cord in water. Wipe the base with a damp cloth, and wash only the removable food container or parts that the manufacturer says are washable, then dry everything before reassembly. A listing that says dishwasher safe may refer to only some parts, so check which. Replace the unit if the cord or plug is damaged.