If you are looking for a bottle warmer, look no further. We compared the top 13 warmers available today, putting them through extensive testing to help you choose. Since 2012, we have purchased more than 23 different warmers and used each to help you pick the right one for your family. We considered safety, warming temperatures and times, usability, and ease of cleaning. When you count the hours spent preparing a bottle while juggling a crying baby or multiples, having a warmer that performs great while fitting with your family budget can make a significant impact on your daily life. Our extensive testing and ratings can help.
The Tommee Tippee 3-in-1 Advanced is a warmer that heats bottles using a water bath. We prefer this method because we believe it is safer and more consistent than steam. The four-button interface is intuitive and straightforward and considers different variables, such as bottle type, milk temperature, and the contents' volume. The large inner chamber will accommodate most wide neck bottles, and the basket allows you to lift shorter containers without risking burned fingers. It earned the highest overall score in our testing and is a device we would gladly use in our own homes.
The large size of the 3-in-1 Advanced may not be ideal for those who have a small kitchen or would like to use it outside the home. The warm time of the Tommee Tippee is not as fast as some others, but we gladly accept a longer wait if it means getting a more consistent milk temperature. Overall, we love this Tommee Tippee product and highly recommend it as your primary warmer.
The Kiinde Kozii is an innovative warmer with an overall performance that helped it stand out from the crowd. With the second-highest score in our review, it quickly became a favorite at home, on the go, and at daycare. It has many notable qualities, including a simple, user-friendly design. It accommodates all bottle shapes and materials, a handy quick start guide, a small footprint, an auto shut-off feature, and a retractable water reservoir. We like the Kozii best because the SAFEHeat technology uses a warm, circulating water bath to heat bottle contents and reduce the risk of nutrient damage.
While not as speedy as steam heat technology nor as fast as much of the competition, the Kozii may not be everyone's first choice. However, even with these minor flaws, we think it is well worth the wait to take advantage of the other beneficial features. The ease of use, versatility, and safety make it a tester favorite.
The Chicco NaturalFit is a simple, straightforward warmer with a budget-friendly price. It is a safe, reliable way to heat your baby's bottle without the bells and whistles that make a product complicated or hard to use. This product uses water bath technology with a slow but consistent warmer. Its strengths lie in health and safety, ease of use, and cleaning. It is multifaceted, compatible with various bottle dimensions and materials, and has a small footprint and compact volume for easy and convenient travel.
This warmer is somewhat slow and could leave your little one fussy while you wait for a warm bottle. However, we believe the lower price and consistent warming temperature are significant and overshadow the downsides, making this wallet-friendly option excellent for most families.
The Tommee Tippee Travel Warmer is an innovative product made with on-the-go families in mind. The insulated flask stores warm water, and the extra-large beaker acts as a warming chamber that is big enough to hold most bottles, pouches, or baby food containers. To prep the warmer, all you need to do is boil water beforehand, and then all parts fit together in a self-contained unit that fits neatly in a diaper bag or stroller basket. A hot water bath brings milk to a temperature suitable for a baby without using an external warming source.
Unfortunately, the Travel Warmer's ultra-simplistic nature lacks safety features such as an auto-shutoff or end-of-cycle alarm. It also heats bottles slowly and somewhat inconsistently because there is no circulation. If you want movement in the water, you must swirl the beaker manually. Despite these drawbacks, if you are looking for a convenient way to warm up your baby's food while away from home, the Tommee Tippee Travel is a great potential contender.
Having researched more than 35 warmers over time, we've tested more than 23 contenders side-by-side. We measure multiple factors such as warming temperatures, warming times, ease of use, and cleaning ease. Our extensive and detailed testing took place over several months and in various settings, including in-house at BabyGearLab, tester's homes, and daycares. Our test process includes more that 15 individual tests for temperature accuracy, temperature changes over time, and monitoring of how temperatures change over time to simulate what happens if parents forget to remove the bottle. We think the extensive heat monitoring tests are imperative to finding a safe and easy-to-use warmer. All warmers are not created equal, especially when it comes to ensuring that your precious breastmilk is not overheated. We focused on metrics such as health and safety, ease of use, warming efficiency, and ease of cleaning to find the best during our extensive testing. Our scores reveal the performance of each warmer and the differences between each.
At BabyGearLab, we provide readers with the world's most scientific reviews of baby gear. Leading our team since 2012 is founder Dr. Juliet Spurrier, a board-certified pediatrician and mother of two. Using her knowledge of all things baby and experience as a medical practitioner, Dr. Spurrier selects products with safety and efficacy in mind to develop the important metrics included in testing. Also contributing to this review is Senior Review Editor, Abriah Wofford, as well as Senior Review Editor and mother of two, Wendy Schmitz, both testing and reviewing baby gear at BabyGearLab since 2015 and 2014, respectively.
Good To Know: It's important that you never use the microwave to heat baby's milk. The high microwave heat can create dangerous "hot spots" that can scald a baby's mouth. Additionally, overheating causes deterioration of the nutrients in breastmilk that are important for a baby's health and immunity.
Analysis and Test Results
While it isn't an absolute necessity, some parents may find having a bottle warmer is a welcome addition to the baby gear arsenal. If you have multiple babies or are only bottle-feeding, a simple, convenient, and safe option for heating your baby's meals could be a big time saver or a stress reducer. Think of it as an extra set of hands!
When preparing for a baby, costs add up quickly. Luckily, if you need a warmer, most of them are reasonably inexpensive compared to other baby gear items. The award winners in this group range in price from $35 for the Chicco Natural Fit to $70 for the Kiinde Kozii. The top-ranked warmer, the Tommee Tippee 3-in-1 Advanced, is $43. If you aren't sure how often you will use one or even if you need one, but you want to have one on hand just in case, the Chicco is your best bet at a wallet-friendly $35. It is hard to go wrong with the Chicco. It earned a higher rank and has a faster heat time than others.
Health and Safety
Health and safety should be the top priorities when choosing a bottle warmer. When warming a bottle, you should not overheat or unevenly heat the contents. Doing so can cause hot spots or alter breastmilk's nutritional or immunologic value. The best way to handle breastmilk, while upholding the nutrition, is to avoid exceeding a temperature of 104 F / 40 C. Ideally, milk stays at or below body temperature, 98.6 F / 37 C.
We quickly formed preferences for specific features during testing. We became partial to products with warm water bath technology over steam heat, mainly because they aren't as hot and have a reduced risk of a scalding injury to you and your baby. Bottles tend to come out of these warmers slightly cooler and more comfortable to handle. There is also a lower likelihood of overheating internal contents.
The Kiinde Kozii and the Tommee Tippee 3-in-1 Advanced earned satisfactory health and safety scores. Both products rank among the highest of any tested products, and both utilize a water bath warming method.
Overheating Breastmilk Results in Nutrient Loss
The ideal drinking temperature for a baby's bottle will match that of your body, 98.6F/37C or less. So it is essential to pay close attention to your warming process, especially regarding breastmilk. As a living substance, breastmilk includes an incredible array of beneficial nutrients, like enzymes and probiotics, immune factors (such as IgG and IgM antibodies and immunoglobulin A), complex growth factors, and hormones.
We did a comparative, controlled heating test to differentiate warmers in health and safety. We determined which options were more likely to heat to recommended temperatures and successfully maintain breastmilk nutrients. We measured maximum temperatures at the manufacturer's recommended settings and fully cranked the maximum settings to account for the worst-case scenario if a user doesn't follow instructions. We also left the bottle in the warmer for up to 12 minutes to see how warm milk gets if you forget to remove the bottle or can't get to it right away.
At recommended settings, we found that the Kiinde Kozii, Tommee Tippee 3-in-1 Advanced, and the Chicco NaturalFit stayed below 104 degrees for the most time while still being warm enough for a baby. The Kiinde was also the fastest to reach proper warming temperatures without overheating out of these three options. The Kiinde Kozii has the lowest temperature at shut-off, and the Tommee Tippee 3-in-1 Advanced is closest to body temperature at shut-off.
The Munchkin Speed earned the lowest score for health and safety in our tests. This unit is a steam product that can cause burns if the steam makes contact with your skin. Also, if it is accidentally left in the warmer, the Munchkin Speed overheats the bottle after shut-off. It definitely heats quickly, reaching 97F in about 2 minutes. But if you are distracted by a dirty diaper or crying infant, the bottle can quickly overheat, reaching up to 137 degrees in 5 minutes and 147 degrees in 12 minutes. Both are alarming temperatures.
Overheating is Possible at Maximum Settings
In a second test, we set them to the maximum heating setting (not the manufacturer's recommended setting) to see if the warmer's misuse could result in overheating breastmilk.
Once again, we were impressed with the Chicco Natural Fit, which consistently heats to safe temperatures that are neither scalding nor degrade breastmilk. Its performance in our basic test and the maximum settings test show consistency and less chance of error.
The Kiinde claims that they rely on a patent-pending SAFEHeat technology to prevent milk from overheating using a circulating warm water bath. However, we were able to get it to overheat in our maximum heating test. The Kiinde continued to warm at the highest setting, eventually reaching temperatures we consider to be too high. After 8:30 minutes, it crossed 104F. After 12 minutes, the milk temperature rose to 122F. We conclude that following Kiinde's recommended settings is crucial for best results.
The Munchkin Speed is the fastest and the most likely to overheat the bottle's contents. When used at maximum heating settings (not recommended), the steam heat warmer pushed temperatures up to a scalding 150 F. This is way too hot to warm anything baby will drink, which is a severe concern for us. Even though this test used settings outside of the manufacturer's recommendation, we suspect many parents could make this mistake for the sake of time or forget the bottle is in the warmer.
Always swirl a warmed bottle for about 30 seconds to remove potential hot spots. You MUST check the contents' warmth by putting a few drops on your inner wrist to ensure the temperature isn't too hot or too cold for your baby. The skin on your inner wrist is thin and sensitive to temperature. Milk warmed to body temperature will feel barely warm, not too warm, and definitely not hot.
Ease of Use
If your baby is exclusively bottle feeding, you may find yourself using a warmer every 2 or 3 hours. Having a simple, easy-to-use warmer with clear instructions can make it easier for you and other caregivers who may help you. We based our ease of use results on factors such as assembly out of the box, clear and specific instructions, quick set-up for each use, versatility, compatibility, portability, and useful elements like a water reservoir, timer, and auto shut-off.
The top-scoring warmers in the ease of use metric include the Tommee Tippee 3-in-1 Advanced and the Chicco NatrualFit. Both are simple in terms of setup and use. They don't require much prep or maintenance, and the user interface is intuitive and helpful to most people.
A warmer with an integrated or attached water reservoir, like those found in the Kiinde Kozii, Chicco NaturalFit, or Dr. Brown's Deluxe can save you time and effort. You don't need to add water with every use. Like the Boon Orb, Steam-based warmers require you to fill a small vial with a precise amount of water each time you use the unit. It's easy to spend almost as much time filling the vial as you do waiting for the bottle to warm, which can be a tedious process.
Setting Timer and Warming Charts
Most products include charts to help you set the timer for perfect warming. These charts can range from simplistic to frustrating. Many of the instructions give directions for different bottle sizes, materials, and temperatures. Having multiple directions can complicate matters, but it is essential to consider all the variables.
We found that some products need a bit of a fiddle factor to achieve the best results. Be aware that you will inevitably go through trial and error before you consistently reach the perfect setting for daily use. However, it shouldn't take more than a day or so of fiddling to get a working mojo going with your new warmer. We appreciate that the Kiinde Kozii timer setting displays minutes. The Chicco NaturalFit also has simple controls with a dial turned to either baby food or bottle warming. The Tommee Tippee 3-in-1 Advanced has a few more settings, but the snowflake and bottle icons make it simple to understand.
A few steam-based warmers like the Munchkin Speed and the Boon Orb include a lift-out "basket" to remove the bottle since it can become too hot to handle after a warming cycle.
Compatibility and Versatility
If your baby is attached to a particular bottle and you are shopping for a bottle warmer, you will need to be sure it is compatible with your preferred bottle's width, height, and material. Dr. Brown's Natural Flow Glass baby bottles are narrow and tall and fit well in a Dr. Brown's Deluxe warmer. However, don't expect this unit to accommodate a wide-mouth design bottle like the Tommee Tippee glass feeding bottle or the Comotomo. Some warmers are more versatile, which can be helpful if you need to switch bottle types at any point or plan to use breastmilk storage pouches.
If you are using glass bottles, make sure the bottle warmer you choose is glass compatible. For example, Boon Orb is a glass no-go as rapidly rising temperatures increase breakage risk.
If you are unsure what bottle your baby will prefer, go for a versatile warmer like the Tommee Tippee 3-in-1 Advanced, Kiinde Kozii, or Chicco NaturalFit. All three of these warmers are compatible with most bottle shapes, sizes, and materials, including breastmilk storage pouches.
Portability and Footprint
If you want to travel with a bottle warmer, have limited kitchen counter real estate, or want to fit your warmer inside a height-restricted area, a compact warmer is essential. The Chicco NaturalFit has a small footprint and doesn't have small parts that could get lost, so it is an excellent travel option. The Tommee Tippee Travel Warmer is explicitly made for an on-the-go scenario and is also one option that does not require electricity. If you worry about height, shy away from the Baby Brezza Safe and Smart, the Beaba BabyMilk, and the Dr. Brown's Deluxe, which are all taller than 10.5 inches. These warmers could struggle to fit under upper cabinets.
Warming efficiency is the ability to consistently heat a bottle's contents to a similar temperature at a similar rate each time. No cooling period or shorter wait time between heat cycles is beneficial, especially if you have multiples or are in a daycare setting.
The fastest warmers in our tests are the Dr. Brown's Deluxe and the Boon Orb. Not surprisingly, these particular warmers utilize steam heat technology, which helps them warm bottles quickly.
However, as mentioned earlier, steam heat has its drawbacks. For example, the Boon Orb's steam heat technology is incompatible with glass bottles due to breakage potential during rapid temperature changes. More importantly, steam warmers present a real risk of overheating milk if used at their maximum settings.
With the water bath warmers, the warming process takes significantly longer. The Kiinde Kozii was 80F at 5:30 minutes, and the Tommee Tippee 3-in-1 Advanced was almost 90F at 5:00 minutes. The Chicco NaturalFit took a little longer with 80F at around 8:30 minutes. We think these longer times are worth the wait so that the bottle contents aren't too hot, and the risk of steam-related injury isn't a concern.
We recommend thawing frozen breastmilk overnight in the refrigerator before use. Thawing will shorten warming time, which means you'll be able to get that hungry baby drinking faster.
Consecutive Warming Cycle Wait-Time
While some warmers allow you to run through two back-to-back cycles, others may have recommended wait times in between use. Immediately starting another warming cycle is helpful if two or more bottles are being heated one after another. It's also handy if the first cycle doesn't get the temperature high enough for the baby's liking, and you need to add more time. We found the longest wait time between use is around 30 minutes or when the warmer has thoroughly cooled. The Chicco NaturalFit is one of these, which is a deal-breaker for some families. The Tommee Tippee 3-in-1 Advanced has no listed wait time, while the Kiinde Kozii has instructions to take 30 seconds off the subsequent bottle's warming time if the machine is still warm.
Ease of Cleaning
Regular cleaning and maintenance are essential, but the frequency (every day vs. every use) depends on the unit. The external cleaning process typically involves a quick wipe with a dry cloth.
However, because warmers use water, mineral deposits can build up internally. These deposits mean you need to descale the units every few weeks, particularly in areas with hard water.
The descaling or demineralization process removes calcium and lime deposits that can build up on surfaces inside the warming chamber and the heating element after prolonged contact with water. Soaking the bottle warmer's internal surfaces in a vinegar solution, usually explained in manufacturer instructions, will remove deposits. The Kiinde Kozii has special instructions to soak the unit with a mild 1:50 bleach/water solution every few weeks. Some products require overnight soaking, like the Chicco NaturalFit. This wait time could be a deal-breaker if you rely on your warmer for every feeding.
We also considered how difficult it is to get things very clean. Some products have hard-to-reach nooks and crannies—the Dr. Brown's Deluxe has a narrow and deep warming chamber and a poorly designed water reservoir that makes it impossible to get inside for scrubbing.
The units that scored well in this metric had fewer parts and accessories and easy-to-access water reservoirs. The Tommee Tippee Travel Warmer is simple to clean and does not require descaling at all. Another is the Boon Orb, while the rest of the units finished slightly lower with similar instructions and effort levels for good descaling. Our least favorite to clean and the one most likely to accumulate residue or mildew build-up even with regular cleaning is the Dr. Brown's Deluxe.
In our ongoing process of testing the most popular bottle warmers over the last eight years, we've gathered a lot of information we'd like to share about essential qualities and features you'll want to look for when making a purchase.
Why Purchase a Bottle Warmer?
While not necessary, you may find it convenient to have a warmer if you're warming more than one or two bottles a day or your baby prefers milk to be at a specific temperature every time.
The bottom line is that while it can be a convenient time-saver, a bottle warmer is not a must-have baby product. So, let's look at the alternatives side-by-side to help you assess whether the cost justifies the convenience.
Avoid Overheating Breastmilk
Breastmilk starts degrading in nutritional and immunological value at 104 F/40 C, but deterioration accelerates as temperatures climb higher than 113F/45C. You should aim to warm the baby's milk to approximately 98.6 F/37 C (body temperature) or less.
Three Ways to Warm a Baby Bottle
It's the middle of the night. Baby is hungry, and it's your turn to feed him. Time for the midnight shuffle. Do you grab the baby and then go warm the bottle or vice versa? It depends on how you plan to heat the milk.
Good options for warming the bottle include:
Stand at the sink while swirling the bottle under warm tap water (not too hot)
Put the bottle into a bowl of warm water with intermittent swirling (again, not too hot)
Use a bottle warmer
The first two options require constant attention, asking a lot from a half-asleep parent with a hungry, crying baby. The advantage of a dedicated warmer is that your hands are free, and you can focus on your baby's other needs, like a diaper change or cuddle time while you wait.
Is it worth it? That's a personal decision, but many parents find the convenience worth the cost, especially if you plan to bottle feed or share night duties with your partner. There is less room for error, it is more efficient, and we think it is well worth it to catch up on some valuable sleep.
No Microwave, No Boiling Water
You should never use the microwave to heat your baby's meal, not for formula, breastmilk, or purees. High, focused heat generated by a microwave oven can result in dangerous "hot spots" in liquids and solids. If not thoroughly mixed and checked, these hot spots can result in scalding injury to the baby. Also, the unpredictable heat of a microwave is likely to raise at least some, if not all, of the breast milk above temps of 104 F/40 C, the temperature at which beneficial enzymes, nutrients, and antibodies begin to degrade, reducing healthful benefits for the baby.
Furthermore, putting a bottle in a pan of boiling water or recently boiled water can also lead to overheating or potential damage to glass and plastic bottles.
Selecting the Right Product
Apart from offering a hands-free method for heating milk, a great bottle warmer should deliver on the following five factors:
Health & Safety — Avoiding the risk of burn injury and providing nutritionally whole breast milk at an appropriate temperature for the baby is essential. Generally, a good rule of thumb is to heat as close as possible to an average body temperature of 98.6F/37C and not much higher. Below, we discuss how to preserve the total nutritional value of breast milk.
Warming Efficiency — Ability to warm contents quickly and consistently
Ease of Use — Easy to operate and maintain
Versatility — Accepts different shaped bottles of any material
Portability and Footprint — Easy to transport and fits in your kitchen
Preserving Breastmilk Nutrition
As we describe in our breastmilk storage advice, your breastmilk is "liquid gold." Its nutritional content is invaluable for your baby, but it requires special care, or overheating can degrade the nutrients by overheating.
Once you warm breast milk to temperatures higher than 104 F/40 C, its nutritional and immunological value begins to deteriorate, both of which are crucial to a baby's health. However, degradation does not become severe until temperatures rise above 113F/45C. For example, in a study conducted by the University of Manchester, breastmilk heated for 10 minutes at 113 F/45 C showed a 10% loss of essential nutritional activated enzymes. And just 1 minute at 131 F/55 C results in a 50% loss of activated enzymes, but no significant damage occurred after 20 minutes at 104 F/40 C (or lower temps). Even if the milk does not feel too hot for the baby, there are still some risks of overheating.
Luke Warm, Not Hot
Keep in mind that the ideal breast milk temperature is around body temperature, 98.6 F / 37 C, or less, which feels lukewarm.
Options and Features
Bottle warmers come in all shapes and sizes and utilize one of two methods to prepare your baby's meal. The options include a warm water bath or steam heat. A few products offer both.
A water bath gently warms your baby's meal by circulating warm water around the bottle. They tend to heat slower but provide more consistency without the high temperatures required to produce steam. We recommend a bottle warmer that uses water bath technology for a few different reasons. The benefits include a gentle warming process that helps breastmilk retain maximum nutrients, maternal antibodies, and other potential health-promoting agents. We also consider it safer as warm water is not nearly as hot as potentially scalding steam. Of the products we tested, the majority are water bath warmers.
To warm a bottle using steam, water inside a reservoir comes into contact with an internal heating element (such as a hot plate), generating steam and raising the temperature inside the mostly enclosed warming chamber. While this method is often faster than a water bath, the hot water and scalding steam can rise to extremely high temperatures. The result? The bottle's exterior is often wicked hot after a heat cycle and may need to cool down for a bit before being serviceable, and if the warmer contents were to spill, there is a potential risk of burn injury. Steam does not heat evenly, resulting in potentially significant temperature variations throughout the contents of a heated bottle. Hot spots are also a risk without thoroughly mixing and then checking the temperature. In our opinion, the high temperatures that come with steam carry unnecessary hazards.
Lastly, because steam heat more easily generates high temperatures, there is an increased potential for temperatures to exceed 104F/40C and cause a nutritional degradation disaster. A few of the steam units we tested make it much too easy to overheat breastmilk, resulting in a significant nutrition loss. The warmers in our review with steam heat technology are the Munchkin Speed, Dr. Brown's Deluxe, Beaba BabyMilk, Baby Brezza Safe and Smart, and the Boon Orb.
Baby bottles can be narrow, wide, short, or tall, and not all shapes fit inside the warming chamber of every machine. Also, material limitations may mean that a certain warmer isn't compatible with a particular baby bottle. For example, you cannot use glass bottles in the Boon Orb. Also, some machines (usually steamers) only accept plastic or shatter-resistant glass because the quick heating process may cause the weaker glass to break from temperature shock.
Suppose you are uncertain which bottle type and nipple your baby prefers (i.e., they haven't been born yet). In that case, we recommend choosing a bottle warmer that accommodates a wide variety of bottle sizes and materials. The Kiinde Kozii and the Tommee Tippee 3-in-1 Advanced are both excellent choices that fit every bottle and pouch we tried. The Chicco NaturalFit is suitable for many different bottle types but is not compatible with breastmilk storage pouches.
Auto Shut-Off Feature with Timer
We highly recommend buying a bottle warmer with an automatic shut-off feature. Many warmers have either a timer or a temperature reading indicating the cycle's end. The timer-based auto shut-offs are reliable, easy to use, and simple to read in our testing. They also allow for some personal adjustments, and once you've found the time setting that matches your baby's preferences, it's easy to remember for the following uses. Plus, it's nice to know how much longer you'll need to wait before the bottle is ready. The warmers in our review that do not include this feature are the Philips Avent Fast, the Grownsy, the Tommee Tippee Easi-Warm, and the Tommee Tippee Travel Warmer.
In theory, a temperature-based shut-off is ideal. However, we found that this method doesn't always work very well in practice. It often leaves you with under-heated bottles and the possibility of overheating incidents. The one exception is the Chicco NaturalFit, which consistently heats to an adequate temperature without going over 100F/37.8C.
End of Cycle Signal
An audible beep at auto shut-off is one of our favorite features to keep parents on track. It is so easy to get distracted and lose track of time while a bottle is warming. Many warmers in our tests continue to heat the milk even after the auto shut-off if the bottle is not promptly removed. Because breastmilk nutrients begin to degrade significantly at temperatures above 113F/40C, preventing it from overheating is imperative.
Some warmers require that you add water before each use. Others have a built-in reservoir that monitors water levels for you and lasts through several cycles. Kiinde Kozii, Chicco NaturalFit, and Dr. Brown's Deluxe can all run multiple rounds without a refill, saving you valuable time and effort or at least some late-night frustration.
Making Your Selection
One of the first steps in narrowing down your options is considering each product's various features and abilities. Although they are often overlooked, small perks can make the difference between two otherwise very similar contenders.
Consider Warming Efficiency
Since a bottle warmer's primary purpose is to provide your baby with a tasty meal, warming efficiency is a top priority. Ideally, you can toss in a bottle, tend to the baby, and return to a perfect bottle every time; no re-dos, no accidents. Some warmers can produce consistent results every time, while other warmers vary from cycle to cycle, leaving you with an overly hot or still lukewarm bottle. Because time is precious, a consistent warmer like the Chicco NaturalFit is greatly appreciated; it heats reliably close to the ideal temperature of 99 degrees each time. The Kiinde Kozi also warms consistently but has a lower final temperature.
Is It Easy to Use?
Before a bottle warmer can fit seamlessly into your routine, you have to learn how to use it, and some units have a steeper learning curve than others. The warmers in this review vary in the number of parts they include. Some are a single part with no accessories, like the Kiinde Kozii. Others have many extra components, such as adapters, bottle baskets, or measuring devices. Other ease-of-use factors to consider are the setting options and the clarity of heating charts. How hard are they to master? No matter what, your operation should be as close to the instructions as possible.
You will go through some trial and error before finding the perfect setting that gives you consistent results for your bottle type and starting milk temperature. However, it shouldn't take more than a day or so of fiddling to get your machine working correctly; after that, it should be a piece of cake. The Kiinde Kozii, the Tommee Tippee 3-in-1 Advanced, and the Chicco NaturalFit are the easiest to use warmers.
What's Your Bottle Style?
Before choosing a warmer, think about the type of bottle you'll be using. As we mentioned above, some warmers don't fit extra-wide mouth bottles like the Tommee Tippee. Some warmers, such as the Boon Orb, have available adapters for different bottle sizes. The Kiinde Kozii, Tommee Tippee 3-in-1 Advanced, and the Chicco NaturalFit work well with all bottle types, and the first two are compatible with breastmilk storage bags.
Do You Have Multiples?
If you have twins or two babies that are close in age, you'll want to know if a warmer has a required wait time between running cycles. Starting consecutive warming cycles is vital if you need to heat two or more bottles in a row. It's also handy if the first cycle doesn't quite get the milk warm enough and you need to add more time. The longest wait time we found between uses was close to 30 minutes (or until the unit cools down) for the Chicco NaturalFit, while the Tommee Tippee doesn't list a wait time at all.
Can You Keep it Clean?
This metric is pretty self-explanatory but something you'll want to consider. Although manufacturers don't always require daily cleaning, basic maintenance is essential to keeping your product running correctly. We found that you can usually reduce cleaning to a simple wipe-down. Since all of the machines we test use water in some form or another, the most common issue lies in formingmineral deposits. This accumulation typically happens in the warming chamber or directly on the heating element.
Every warmer we tested instructs you to use either a descaling agent or a vinegar solution for an occasional deep clean. This process, called descaling, gets rid of these deposits. We also find that warmers with a reservoir system carry a higher risk of building mold and mildew, so they should be cleaned more frequently.
Our main objective while testing bottle warmers is to assess the safety and see if each could warm a bottle of milk consistently and efficiently without overheating or damaging the contents' nutritional value. Secondary factors include ease of use and cleaning. We test each warmer extensively and perform hours of research to ensure we include the best products on the market.
Health and Safety
We perform two different controlled tests using the same protocol for each warmer. We pour 4 ounces of milk into a 4-ounce Lifefactory Glass Bottle with a silicone sleeve. Each test starts with milk between 42 F/5.6 C to 45 F/7.2 C. We then place a professional-grade digital thermometer directly in the center of the bottle for a temperature reading every 30 seconds.
We anticipate that bottles may be forgotten and left in the unit longer than the recommended time, so they continue heating. To recreate this scenario, we keep the bottle inside the warmer and measure temperatures every 30 seconds for a full 12 minutes.
In our tests, we use a glass bottle with a silicone sleeve. Silicone is an insulator, so it takes longer to conduct heat than glass alone or plastic. Therefore, our milk temperature measurements are likely low side when compared to a plastic bottle. However, the times are still accurate relative to one another and give an objective indication of which warmers heat faster than others.
Manufacturer Warming Recommendations
Closely following the manufacturer's instructions for the recommended warming cycle, we record milk temperatures every 30 seconds in each warmer. We note the temperature at the time of auto-shutoff, and if there is no auto-shutoff feature, we let the warmer run for a total of 12 minutes, then take a final reading.
Maximum Heat Settings
In addition to recommended usage, we also test each product by cranking a room temperature warmer to its maximum settings, using the same setup of 4 ounces of refrigerated milk in a Lifefactory glass bottle and the included sleeve. We record temperatures every 30 seconds for a maximum of 12 minutes.
Why did we do this?
We don't condone stepping outside the manufacturer's instructions, but let's face it, not everyone is going to play by the rules. We suspect some parents will attempt to heat the bottle as fast as possible when faced with a crying baby, potentially disregarding manufacturer recommendations. We test how high the temperatures ascend when the warmer runs at full throttle for 12 minutes to assess the potential damage.
Ease of Use
When assessing ease of use, we consider how simple it is to get the product ready for its first use right out of the box, the number of pieces to assemble, ease of day-to-day operation, and the clarity of instructions. We carefully read the directions, review the initial assembly, and note how easy it is to use daily or nightly. Over several months, we found that elements such as the warming chart's clarity and the ease of adding water make a difference in obtaining consistent results. We appreciate simple units for a caregiver to use without significant coaching.
We use 99℉ as our ideal standard milk temperature to evaluate warming efficiency. Reason? That is roughly the temperature of milk coming straight from the breast, and we assume your baby prefers this warmth. Warmers that bring the milk closer to 99℉ receive higher scores for this metric. We also consider auto shut-off features and warming wait time during our warming tests.
Manufacturer Recommendations: Auto Shut-Off Time & Temperature
Following each manufacturer's warming recommendations, we record the time and temperature at auto shut-off.
Consecutive Warming Wait Time
The last factor in warming efficiency is the consecutive warming wait time. We took a look at how quickly you can restart the warmer to heat a second or third bottle. This info is crucial if you have more than one infant to feed, if a baby is still hungry after one bottle, or are using the warmer in a daycare setting. Some products require you to let the machine cool completely before starting a new warming cycle, while others ask that you reduce the next bottle's warm time. Allowing the warmer to completely cool before using it can take a while and may not be ideal if you've got more than one hungry baby on your hands.
Ease of Cleaning
The manufacturer recommends using a damp cloth for each product we tested to wipe all surfaces (inside and out) at least every other day. They all require occasional descaling for the removal of hard mineral deposits to keep in good working order. Descaling frequency is different for every warmer and depends heavily on the water hardness in your home. It can range anywhere from once a week to once a month.
You might feel that a bottle warmer is a "nice-to-have" instead of a "need-to-have." However, it can help create simplicity and efficiency to any feeding routine, formula, or breastmilk. The perks are arguably well worth finding a great warmer for busy parents, especially if they have multiples. To help you find the best bottle warmer for your needs, we put each product through extensive testing. We evaluate each option's safety, warming efficiency, and ease of use and gauge its functionality in the real world. We now can confidently single out the top performers and make trustworthy recommendations for every family, no matter your needs or budget.
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BabyGearLab was founded by a Pediatrician Mom with a mission to provide a reliable, independent, source of information to new parents. Our experts have tested thousands of baby and kids products to share key performance, health, and safety findings. We spend tens of thousands of dollars crash testing car seats to inform our ratings. And, we combine our review work with gobs of expert parenting advice. To assure complete independence, we buy all the products we test ourselves. No sponsored content. No ads. Just real, honest, side-by-side testing by people who care.