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Can You Microwave Hot Water Bottles?

Updated: Jan 21, 2023


Hot water bottle and microwave icons

You shouldn’t microwave your hot water bottle unless the manufacturer indicates the hot water bottle is microwave safe. While hot water bottles made of rubber and PVC are not suited for microwave use, more recently commercialized silicone hot water bottles can be heated in microwave ovens.


How to know whether my hot water bottle is microwave safe?


If your hot water bottle is made of rubber or PVC, it’s likely it won’t be suited for microwaves. You can check this on the hot water bottle itself or on the instructions you received with the packaging.


If you haven’t kept the instructions, refer to the brand’s website or customer service and indicate the exact hot water bottle model you own - and the material it is made of - so they can assist you.


In doubt, do not heat your hot water bottle in the microwave and fill it with warm water from the tap or your kettle. If you use your kettle, remember not to pour boiling water into your hot water bottle as it may damage the inside of it.


Microwave

Types of hot water bottles that are microwave safe

Hot water bottles made of food-grade silicone are microwave safe, as they can resist extreme heat temperatures, preventing them from melting. In addition, they do not contain toxic chemicals such as BPA, BPS, or phthalates.


Hot water bottles made of silicone can usually be heated within 3 minutes in a microwave.


What can happen if I heat my hot water bottle in a microwave?

Hot water bottle in bed sheets

As previously mentioned, do not use a microwave to heat your hot water bottle if you’re not sure of its suitability.


BPA release

If your hot water bottle is made of rubber or thermoplastic, it may contain BPA (Bisphenol A). Heating such hot water may lead to the release of this harmful toxin, in addition to others. This typically happens when you heat certain types of plastic.


To be safe, your hot water bottle needs to be BPA-free, which is usually the case with silicone hot water bottles, made of food-grade plastic.


Plastic melting

For some types of hot water bottles made of rubber, for instance, heating your item in a microwave may lead to the outside part of the hot water bottle melting.


In addition to releasing toxins, this is also a burn hazard and may lead the severe injuries when you take the hot water bottle out of the microwave.


Other ways to heat your hot water bottle

If your hot water bottle is not suitable for microwave use, heat it the traditional way, as outlined below.


Fill it with water from your kettle

One of the most common ways to fill a hot water bottle is to use water from the kettle. This takes a bit more time, is less energy-friendly and has a higher cost for you and the environment.


Heat water in your kettle and let it cool down for approximately 5 to 10 minutes to make sure the water is not boiling anymore. Carefully pour water into the hot water bottle while placing it over the sink to prevent hot water from accidentally dripping on your feet and legs.


A common mistake is to pour boiling water into your hot water bottle. Do not do this as it might damage your hot water bottle from the inside and lead to leaks, making your hot water bottle dangerous to use.


Hot water bottle filled with kettle

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