Buying guide for best rubber hot water bottles
In a digital culture dominated by smart devices and USB plugs, rubber hot water bottles might seem like relics from another age, but this old-school tool is more useful than you realize.
Rubber hot water bottles are thick, sturdy pouches that you fill with hot water and apply to your body to relieve pain or discomfort. People use them to soothe everything from sports injuries to menstrual cramps and winter evening chills. The bottles seal with a stopper to prevent leaks, so they won’t drench your bed, ruin your phone, or soak your favorite paperback.
Aside from the source used to heat your water, rubber hot water bottles use no energy whatsoever. This means, unlike a heating pad or electric blanket, they don’t tether you to an electrical outlet. This makes them safer for children to use, even in bed. Hot water bottles are portable, going from home to vehicle to work with ease.
Manufacturers have upgraded classic hot water bottles and taken them to the next level, with cutting-edge materials and cute, dual-purpose covers.
Key considerations
Materials
Most hot water bottles are made from two materials: classic rubber and modern thermoplastic. Either way, bottles constructed without seams are usually the most durable.
Rubber: These tried-and-true hot water bottles have been used for decades because they retain heat so well. Rubber bottles are often thicker than plastic, and so they may take slightly longer to start to transmit heat. They’re also opaque, so it can be challenging to gauge the water level. If you’re allergic to latex, using a rubber water bottle can be dangerous.
Thermoplastic: These hot water bottles are made from polymers that are soft and flexible when heated but solid when cool. Many thermoplastic water bottles are somewhat transparent, so you can easily check the water level. They often stay warm longer than rubber water bottles, and can be safely used by people who have latex allergies. However, some are thinner than rubber bottles and may be more prone to leaks and tears.
Metal: Some hot water bottles have metal fittings, which present certain problems. Some metal fittings may rust if they’re exposed to water, which is pretty much guaranteed in hot water bottles. Look for necks and fittings made with stainless steel or other rust-free options.
Some hot water bottles advertise that they can be heated in the microwave. However, for those with metal fittings, it’s out of the question. If you want to warm your hot water bottle in the microwave, be sure that the material can handle it and all the parts are free of metal.
Size
Hot water bottles come in different sizes, holding between 1 and 2 liters of water.
Standard: The standard size is about 2 liters (although you should never fill a water bottle to the brim). Most hot water bottles in this size measure about 11 inches long by 8 inches wide, about the size of a sheet of printer paper. They’re best used for soothing abdominal or menstrual cramps or resting on other large areas of the body.
Midsize: These hot water bottles are usually 1 to 1.75 liters and measure 8 to 10 inches long by 6 to 7 inches wide. They nestle better against smaller areas of the body and are more portable than standard hot water bottles.
Child: Any hot water bottles designated as less than 1 liter are intended for use by children. These are lighter and easier for a child to manage. These bottles also lose heat more quickly than larger bottles.
Expert Tip
Hot water bottles should be replaced about every two years to avoid leaks and tears.
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Features
Texture
The fun, funky patterns on some hot water bottles aren’t just for decoration. Different surface textures are there for a variety of purposes. Surfaces with a ribbed texture on one side diffuse the heat so one area doesn’t get too hot. Sides with flat surfaces provide more intense, targeted heat. A side patterned with a cross-hatch design can split the difference between the two effects.
If you use a hot water bottle with a textured design, monitor your skin for any overheating or burning. You should always use a barrier, whether it’s a fancy cover or a simple towel, between a smooth hot water bottle side and your skin. Doing so helps prevent injury in case of prolonged exposure to the heat. And it never hurts to use a barrier with a textured hot water bottle, either.
Cover
Hot water bottles are intended to soothe aches and pains, but improper use can cause even worse injuries. Leaving a hot water bottle in place longer than 15 minutes can burn your skin if the bottle is filled with piping-hot water. Fabric covers create a buffer between your skin and the hot rubber or plastic. Many covers attach with buttons, snaps, or zippers so that they don’t slide off the smooth surface. Many come with covers made in classic knit designs. Others may feature a cheerful pattern or resemble a cuddly animal. Keep your intended user in mind when considering cover options.
Mouth
Struggling with scalding water is downright dangerous. Look for a rubber hot water bottle that has a wide, funnel-shaped mouth to make it easy to fill.
Color
Once one person in your house starts enjoying a toasty hot water bottle, others will want one, too. Choose a bottle (and cover) in a color that’s uniquely your own, so you can tell them apart easily.
Caution
Never put boiling water inside a rubber hot water bottle. It can cause severe burns if the bottle leaks.
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Accessories
Electric kettle: Cuisinart PerfecTemp Cordless Electric Kettle
Heat the water for your new bottle in a flash with this cordless electric kettle. One cycle will heat more than enough to fill most water bottles to your perfect temperature level. And the kettle can hold a temperature for up to 30 minutes in case the water’s ready before you are.
Rubber hot water bottle prices
Rubber hot water bottles definitely cost less than bumping up the thermostat a few degrees. Most of the hot water bottles we found are of the 1.5-liter to 2-liter size.
Inexpensive: You can find quality hot water bottles starting at around $10. At this price, they are likely made from thermoplastic or thin rubber and may come with a thin knit cover. The bottles themselves likely have a smooth, untextured surface.
Mid-range: The next tier of hot water bottles costs $13 to $15. Hot water bottles in this price range are usually made of rubber or thicker thermoplastic and may have heat-diffusing texturing on at least one side. Some textured bottles may not come with a cover.
Expensive: The most expensive rubber hot water bottles cost $20 and up. These water bottles should be made from rubber or thick thermoplastic and have durable, quality texturing. If you’re paying this much, you’re often paying for a higher-quality cover rather than a higher-quality bottle.
Expert Tip
If you’re concerned your hot water bottle may have a leak, fill it with cold water and inspect it for drips.
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Tips
- Fill the hot water bottle about two-thirds full for the best results. Any more and it may be too bulky to stay in place.
- Look for a tethered stopper. You’ll be less likely to lose the stopper if it’s tethered to the hot water bottle.
- Never use a hot water bottle in bed with an electric blanket.
- Heat the water in a kettle. Bottles filled with hot water stay warmer longer than bottles filled with water that are then heated in the microwave.
FAQ
Q. What’s the safest way to fill a rubber hot water bottle?
A. Use water from an electric kettle or water heated on the stovetop in a tea kettle. Heat the water until it starts making noise in the pot, or feels warm if you wave a hand over the spout - around 110°F to 120°F. Empty the kettle into a heat-resistant container with a pour spout, and add cool water until you can dunk a hand in it without pain. Place your bottle in the sink, grip it near the top, and fill the water bottle two-thirds full. Position the bottle so it’s slightly angled, and lower it to the point where water is visible at the top to remove any trapped air. Close the bottle and feel the outside to ensure it’s not dangerously hot.
Q. Can I sleep with my hot water bottle to keep me warm?
A. Hot water bottles are safe to keep your toes warm when you’re in bed, but they should not be placed on your abdomen or torso. If you roll onto a hot water bottle in your sleep, you may apply too much pressure and cause it to rupture. This will create two unpleasant surprises — soaking your bed and ruining your hot water bottle! If you need to warm your upper body while you sleep, consider using an electric blanket.
Q. How do I keep the inside of my hot water bottle clean?
A. It’s important to drain your hot water bottle fully after each use. Once it’s empty, hang it upside down to drain thoroughly. Don’t clean it with soap or chemical cleansers. This can compromise the material. Just make sure it’s fully dry before storing it, without the plug, in an area that’s cool and out of direct sunlight.
