The Best Bottle Warmers

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.

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.

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:

Happy baby! Nothing's better than a warm meal in the belly.

Credit: Lindsay Ellis

• 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.

Some warmers have a removable basket, like this one on the Dr. Browns, that can help you avoid contact with hot water or steam.

Credit: Abriah Wofford

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.

Water Bath

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.

The Speed has a few different parts including a basket and ring that can be cleaned in the dishwasher. The chamber isn't too hard to clean but you will need to do regular descaling.

Credit: Abriah Wofford

Steam Heat

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.

The Tommee Tippee will fit the widest of bottles with ease.

Credit: Abriah Wofford

Versatility

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.

The Fast has a single dial with multiple setting options and an LED indicator light to tell you when it is warming versus when the cycle is over.

Credit: Abriah Wofford

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.

Dr. Brown's Deluxe is a steam style bottle warmer with a side reservoir.

Credit: Abriah Wofford

Water Reservoir

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.

The Chicco is a slow warmer on par with most water baths with an auto shut off of 5:30 minutes and a content temperature of 80F.

Credit: Abriah Wofford

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.

With three buttons and easy to identify icons the Tommee Tippee is easy to set without the aid of a chart or manual.

Credit: Abriah Wofford

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.

The Kiinde timer knob is straightforward and a no-brainer once you "dial-in" the right time for your bottle and content temperature.

Credit: Abriah Wofford

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.

The water bath technology of the Kiinde is safer than steam bath warmers.

Credit: Abriah Wofford

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.

Credit: Abriah Wofford

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.

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.

Boon Orb Warming Guide

Credit: BabyGearLab Staff

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.

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.

The small graduated tube is difficult to measure due to very small increments so pouring out and starting over happened a lot.

Credit: Ruth and Ben Traxler

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.

Warming Efficiency

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.

Chicco NaturalFit's warming instructions specify that the device needs to be fully cooled before subsequent use (see bottom sentence); in our experience, this took between 15-30 minutes.

Credit: BabyGearLab Staff

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.

The Chicco NaturalFit bottle warmer includes a removable basket insert to help ease the placing and removing of containers.

Credit: Abriah Wofford

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.