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How Do Mini Fridges Work?

There’s one thing that dorm rooms, first apartments, man caves, home bars, and RVs all have in common. They just don’t have that much space. So you have to forgo many conveniences of an otherwise more spacious home. Keeping your food fresh and your drinks cold isn’t one of them.

Then again, you don’t really need to. You can simply buy a mini fridge. As the name suggests, mini fridges are small refrigerators that can keep your food fresh in a tight kitchen or cool your drinks on a game night.

My youngest cousin is a freshman in college. He rented an apartment with a couple of friends recently. Guess who ended up giving them tips on how to equip their (pretty tight) kitchen.

After hours of research, I became somewhat of a specialist on mini fridges. So in this post, I’m going to tell you everything I learned about them.

What is a mini fridge?

A mini fridge is a compact and freestanding refrigerator that you can fit in a tight space. It offers limited storage space for food on one or two drawers, as well as functional door storage for a small number of beverages.

Most mini fridges have a capacity of 1.7 to 4.5 cubic feet. The smallest models are cube-shaped and approx. 17 ½ inches wide, 18 ½ inches deep, and 20 ½  inches tall. Rectangular-shaped mini fridges with more capacity or a freezer compartment are also common.

The smallest 1.7 cubic-feet mini fridges allow you to refrigerate about 7-8 lb produce, 2-3 jars or cans (condiments, sauces, and beans), 2-3 milk cartons (16 fl oz), 2-3 beer cans (16 fl oz) and 1 soda bottle (50.7 fl oz).

Thinking about buying a mini fridge for your home garage or wet bar? The smallest, 1.7 cubic-feet mini fridges, will easily hold a case of 12 oz cans of beer. One case contains 24 cans. Most 2.6 cubic-feet mini fridges hold up to 2 cases of beer (2 cases x 24 cans x 12 oz).

How Do Mini Fridges Work?

Fridges, full- or mini-sized, work thanks to two indisputable facts of physics:

  1. First, when a liquid turns into vapor (evaporates), it absorbs heat. 
  2. Second, when a gas turns into a liquid (condenses), it releases heat.

A fridge is an insulated box for cooling food and beverages. The box contains a storage area surrounded by a closed-circuit system of coils that circulates refrigerant.

The system continuously absorbs heat from the inside of the unit and releases it to the outside. It consists of evaporator coils (on the inside of the fridge), condenser coils (on the back or, on some models, at the base), an expansion valve, a compressor, and the refrigerant fluid that travels through them.

The compressor moves the refrigerant through the system. It adds pressure to the warm fluid that flows through it, which heats it and it turns into vapor (evaporates it). The vapor escapes into the condenser coils on the back of the fridge.

The vapor travels through the condenser coils, cools down, and turns into a fluid again (condenses). The fluid passes through the expansion valve, which sprays it into the evaporator coils on the inside of the fridge.

As the refrigerant condenses, it absorbs heat from the inside of the fridge. As it evaporates, it releases that heat on the outside of the fridge. 

This continuous cycle is how all fridges work.

What to Look For In a Mini Fridge

Picking out a mini fridge? Here’s everything you need to look for:

To start with, the mini fridge needs to fit in the small space you have for it. Before buying one, no matter how compact it looks on the picture, measure the space where you plan to install it. It needs to be bigger than the dimensions of the unit.

Choose what storage capacity you’re looking for. Mini fridges come in all shapes and sizes. Most manufacturers sell mini fridges with a capacity from 1.4 to 4.4 cubic feet. Bigger fridges let you cool more food and drinks, but also take up more space.

Decide if you need a freezer compartment or not. If you eat mostly prepackaged foods (pizza, lasagna, microwavable meals) and frozen vegetables (peas, broccoli, veggie mixes), or you juice frozen fruit for smoothies often, you probably need a mini fridge with a freezer compartment.

Also, some food for thought and one thing to watch out below:

My best advice is to buy a mini fridge with a bigger capacity than you think if you have the space. The price difference is not that big (especially when you consider how many years you’re going to use it) and you’re probably going to need the extra space.

If you plan to put the mini fridge in your backyard or on the porch, buy one designed for outside use. Typically, units designed for outside use are made of stainless steel, have water-tight electrical components, and plastic that won’t warp when exposed to direct sunlight.

How to Install a Mini Fridge

Just like their regular-sized cousins, mini fridges work by pumping heat from inside the unit to coils on the back of the unit (or, on some models, in its base). To work, your mini fridge needs free-flowing air around it to continuously cool these heated coils down.

Your mini-fridge shouldn’t sit too close to the wall, especially if the coils are placed in its back (on most models, they are). Doing so will hinder airflow and keep the heated coils from cooling down. This will reduce the efficiency of your mini fridge and eventually cause it to break down.
While it may be tempting to want to hide your mini fridge for interior design reasons, don’t rush to put it inside an unmodified cupboard or kitchen cabinet. Without circulating air, the heat will build up around the mini fridge, cause it to not work, and most probably damage it.

Ideally, you’re looking to have about 3 inches of space between the back of your mini fridge and the wall.

The second most important thing when installing a mini fridge is to make sure it’s leveled. If you skip this step, your mini fridge will have to work overtime to keep your food and drinks cold, and its door may not open and close properly.

Your mini fridge should come with adjustable legs on each side that allow you to level it by hand. All you need is a carpenter’s level (the kind that you can buy in Home Depot) or a level app on your phone. If you have an iPhone, use the level feature on Apple’s built-in Measure app.

Make sure your mini fridge is perfectly leveled left to right. The front should be tilted about ¼ inches higher than the rear.

Fridges shouldn’t be perfectly leveled. Most units should lean back by approx. ¼ inches, which helps the door to stay shut and keeps water from leaking inside them from the evaporator.

Surprisingly, this is not something that most manufacturers make obvious in their installation guides. But ask any fridge expert—and they’ll go on for hours telling you stories of problems that not tilting your fridge up could create for you.

Will a Mini Fridge Increase Your Electricity Bill?

On average, a mini fridge will add $3.29 per month or $39.49 per year to your electricity bill. The electricity cost will vary with the brand, model, and installation of your unit, as well as with your state, season, and time of day.

Assuming that you’ll leave your mini fridge on 24/7 and that it will run ⅓ of the time, here’s how much it’s going to add to your electricity bill at 13.19¢/kWh (the average cost of electricity in the U.S. in December 2020).

(8 h/day, 30 days)
Monthly CostYearly Cost
70 W16.632 kWh$2.19$26.33
80 W19.008 kWh$2.51$30.09
90 W21.384 kWh$2.82$33.85
100 W23.76 kWh$3.13$37.61
110 W26.136 kWh$3.45$41.37
120 W28.512 kWh$3.76$45.13
130 W30.888 kWh$4.07$48.89
140 W33.264 kWh$4.39$52.65

To estimate the cost of owning a running and mini fridge more accurately, look up the average electricity cost for residential customers on this page in the U.S. Energy Information Administration’s website.

The cost of electricity is listed in U.S. cents per kilowatt-hour (¢/kWh). One kilowatt-hour (kWh) equals 1,000 watt-hours (Wh). Here’s what you need to do to calculate your number:

Determine the power (in watts) of your mini fridge. For example, let’s say that your unit runs on 100W. 

Assume the mini fridge is plugged in 24/7, but works only ⅓ of the time. Since the interior of the fridge is insulated, it doesn’t need to run all of the time.

Your fridge is going to work for 8 hours a day, 30 days per month, 12 months for one year. To get the monthly consumption, multiply the power by 8, then by 30. To get the yearly consumption, multiply the monthly consumption by 12.

  • Monthly consumption = 100W * 8 hours/day * 30 days = 24,000 Wh
  • Yearly consumption = 288,000 Wh

Before you can estimate the cost, you need to convert watt-hours (Wh) to kilowatt-hours (kWh) by dividing the number by 1,000.

  • Monthly consumption = 24,000 Wh / 1,000 = 24 kWh
  • Yearly consumption = 288,000 Wh / 1,000 = 288 kWh

To estimate the cost, multiply the consumption by the figure for your state. If you live in New York, that figure is 19.28 ¢/kWh.

  • Monthly cost = 24 * 19.28 ¢/kWh = $4.62
  • Yearly cost = 288 * 19.28 ¢/kWh = $55.53

Remember that this is simply a ballpark estimate. Though the actual consumption and cost of running your mini fridge should be somewhere there, it also depends on multiple factors.

Do Mini Fridges Make Noise?

Most mini fridges generate low-level noise when running. This background noise is considered normal and usually comes from the compressor. On most makes and models, it is somewhere in the range of 36-43Db. For comparison, the loudness of a whisper is approx. 30-35Db and the background noise coming from a household fan is approx. 35-40Db.

If you’re concerned about background noise, you’re probably considering putting a mini fridge for your dorm room, bedroom, or home office. Some manufacturers sell “quiet” fridges purposefully designed to generate less noise, but they tend to come at a higher price tag.

The best thing to do here is to make your own decision based on your sensitivity to noise. The same level of noise can be barely noticeable to some—and a big nuisance for others.

Will a Mini Fridge Heat Up a Room?

Mini fridges give off heat. All fridges work by continuously transferring warmth from the inside of the unit and dissipating it on the outside. This is done using a closed system of coils, powered by a compressor, that circulates refrigerant fluid.

Contrary to popular belief, you can’t cool a room by leaving the refrigerator open for a long period of time. The fridge will end up generating more heat as its heat-pump system tries to cool its interior.

Are Mini Fridges Safe?

A mini fridge is as safe to use as a regular fridge. Most mini fridge owners put theirs in the kitchen, living room, home office, bedroom, garage, or RV.

As with any appliance, choose a mini fridge from a manufacturer that you can trust and buy it from a reputable retailer. When buying online, check other customers’ reviews.

Register your unit with the manufacturer, especially if they offer an extended warranty. Doing so ensures that you will also be contacted by them in the case of product recalls.

Install the mini fridge correctly. Follow all the instructions in the installation and usage guide provided to you by its manufacturer.

Don’t put the mini fridge near sources of heat, like your stove or a ground-level air conditioning unit. 

Avoid putting your mini fridge in a hot room. It will consume significantly more energy to cool your food and drinks. The average room temperature is 68-72°F (20-22°C).

Do Mini Fridges Use Freon?

Until the mid-1990s, most manufacturers used to add Freon as a refrigerant for their units. Freon is a family of halocarbon products and a trademark of The Chemours Company (ex-DuPont). 

As of January 1, 2020, the production and import of the principal component of Freon, also known as R-22, has been banned by the Environmental Protection Agency (EPA) in the U.S. 

The agency’s ban comes after strong scientific evidence that R-22 damages the Earth’s ozone layer (and therefore contributes to global warming).

Based on the make and model, your mini fridge may use an R-22 refrigerant. As a home appliance owner, the ban doesn’t require you to replace your fridge or its refrigerant fluid.

The chance, according to the EPA, is slim. “Most refrigerators and freezers manufactured since 1995,” the agency says, “contain ozone-friendly hydrofluorocarbon (HFC) refrigerants.”

R-22 is mostly found in HVAC equipment, like AC units and heat pumps. Most manufacturers have changed the design of their systems to use R410A, a chlorine-free refrigerant.

Will a Mini Fridge Work Outside?

Not all mini fridges are fit for use in your backyard or deck. Some units are designed to work only indoors, whereas others are capable of working outdoors.

Outdoor refrigerators tend to have waterproof electrical components, sunlight-protected plastics, and are made from stainless steel so that they don’t catch corrosion and rust.

They are slightly more powerful than indoor refrigerators, which makes them fit for use in warmer climates and starker contrasts of temperature from day to night.

The best place to place an outdoor refrigerator is in an insulated area, like an outside bar, and away from direct sunlight.

Will a Mini Fridge Work on Its Side?

Don’t tilt your mini fridge on its side. It’s best to keep it in an upright position when moving and installing it. Tilting a mini fridge can cause damage to its compressor. The compressor is filled with machine oil that’s held in place by gravity.

Your mini fridge contains a number of fluids in its heat-pump system. When tilted, these fluids can move around to devices and parts where they shouldn’t be—causing damage to the unit’s inner workings.

Why Is My Mini Fridge Freezing Everything?

If your mini fridge is freezing the food inside it, the most common cause is in the temperature dial. Check the temperature dial on your unit and, if possible, set it to a warmer setting. On models that allow you to configure the exact temperature, set it to 40°F (4.4°C).

Another cause could be that the condenser coils on the back of the fridge have caught too much dust. In general, it’s a good idea to pull the fridge away from the wall and vacuum the dust from the pipes every 6 months.

If you’ve tried setting the temperature dial to the correct setting and cleaning dust off the condenser coils, but nothing seems to work, the thermostat could be broken. The thermostat is the device that monitors the temperature and controls it by turning the compressor on and off.

Do Mini Fridges Leak?

Your mini fridge could be leaking water because it’s not properly leveled. Check if your unit is leveled (using a carpenter’s level or a measuring app on your phone), adjust it, and give it 2-3 days to determine if you’ve managed to eliminate the cause for the leak.

A clogged drain pipe can be another reason why your mini fridge is leaking. Use the owner’s manual to determine where the drain hose is located (it’s usually at the back of the fridge). 

Unplug the mini fridge, pull it away from the wall, and find the drain hose. Push a small plastic tube through the tubes to remove any parts of food or packaging that might be stuck.

If you keep the mini fridge in an unheated garage or outside, you could also have condensation problems. As heat from the compressor comes into contact with the cold metal of the fridge, it will condense and turn into water, dripping onto the floor.

Can Mini Fridges Be Recycled?

So far, so good. We covered what to look for when buying a mini fridge. But what if you want to get rid of an old one?

To find out the answer, I consulted with Justin Havre, Team Leader of Justin Havre & Associates. Havre and his team had published a comprehensive guide about the parts of a home that can be recycled.

“If you are trying to upgrade your appliances or downsize, you should consider recycling,” he tells Home Cook World readers. “Mini-refrigerators can be recycled but it’s important to keep a few things in mind when you do.”

“First and foremost, do not attempt to remove the components of a mini-fridge by yourself. This can be dangerous. Do not leave your mini-fridge sitting by the curb, as components and chemicals within can leak out and cause a small environmental catastrophe,” Havre adds.

Instead, he recommends to take it to an EPA-compliant or Environment Canada-compliant facility.

“In America, check with the EPA’s Responsible Appliance Disposal program, or if in Canada, check out the Refrigerant Management Canada program. It is important to be assured that your old mini-fridge will be properly recycled and not lead to an issue.”


Mini fridges: they’re compact, don’t consume that much electricity, and keep your drinks and food cool—even if you live in a dorm room, have a tiny kitchen, or limited space in your wet bar or home office.

Before you buy a mini fridge, make sure it fits the space you have available for it. Ideally, there should be 2-3 inches of space between the back of the fridge and the wall, allowing it to dissipate heat so that it can work well.

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Written by

Jim is the former editor of Home Cook World. He is a career food writer who's been cooking and baking at home ever since he could see over the counter and put a chair by the stove.