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What Are Hot Water Bottles Made Of?

Updated: Jan 21, 2023


Hot water bottle icon types

There are many differents types of hot water bottles on the market today, made of different materials. Most hot water bottles produced nowadays are either made of rubber, PVC, or silicone.


In this article, we provide a description of these different types of hot water bottles, and how resistant these different materials are.


3 different types of hot water bottles

Red hot water bottle

1. Hot water bottles made of rubber

Hot water bottles made of rubber, also known as latex, are the most common ones in the market.


The rubber used for hot water bottles goes through an engineered chemical process making it extremely heat resistant (up to 300 degrees celsius depending on the chosen chemical engineering process).


One of the downsides of rubber hot water bottles is they may cause allergies for certain individuals allergic to latex. Opt for a PVC hot water bottle or a silicone hot water bottle if you're allergic to latex.


Rubber hot water bottle manufacturers advise consumers to replace their hot water bottles every 2 to 3 years. Just like PVC hot water bottles, changing them yearly may be a safer option, especially if you’re using them for children.



2. Hot water bottles made of PVC

PVC hot water bottles, also known as thermoplastic hot water bottles, are an alternative to those made of rubber. PVC stands for polyvinyl chloride, one of the most produced types of plastic. Hot water bottle manufacturers add another component to PVC to make it flexible, as hot water bottles typically are.


Opting for PVC hot water bottles may be better for people who are allergic to rubber.

One of the main differences between PVC and rubber hot water bottles is that the former can be transparent and aesthetically customizable.


PVC hot water bottle manufacturers advise users to replace their hot water bottles every 2 to 3 years. To be on the safe side, and depending on the quality of your hot water bottle, it may be better to change them yearly.


One of the downsides of thermoplastic hot water bottles is they are less resistant and more prone to leaks. On the other hand, they preserve heat longer than those made of rubber.


Red hot water bottle

3. Hot water bottles made of silicone

More recently, some manufacturers have introduced hot water bottles made of silicone into the market. These are said to be more resistant to damage from hot water in the long run, especially compared to rubber.


In addition, silicone hot water bottles are odourless and food safe as they don’t contain any chemicals (e.g: BPA, BPS, phthalates) usually added in the manufacturing process. Unlike those made of PVC and rubber, silicone hot water bottles can be heated in microwaves, in less than 3 minutes for most products on the market.


Like those made of rubber and PVC, silicone hot water bottles are recyclable.


Hot water bottle price range by type

Type of hot water bottle (without cover)

Rubber

PVC

Silicone

Price range

10 - 70 euros

13 - 70 euros

15 - 50 euros

Approximate price ranges from Google and Amazon, 2022


These price ranges are not set in stone and vary according to bottle sizes, brands, and quality. As you can see, each water bottle type can be purchased within similar price ranges.


How is a hot water bottle designed?

Hot water bottle design

The cap/stopper

The hot water bottle cap is the part you screw on and off when filling your hot water bottle. These caps are designed to completely seal the hot water bottle if screwed on correctly.


Make sure you double check you screwed the cap back on before use. As a test, turn your hot water bottle upside down above your sink and squeeze it gently to see if there are any leaks.


The mouth

The mouth of your hot water bottle is designed to prevent you from spilling water on your hands and fingers as you are pouring it into the hot water bottle.


Make sure you check no water stayed in the mouth after having filled your bottle, as even a few drops of hot water may burn you.


The neck and body

The neck is designed to make filling the hot bottle easier and more practical. The body is the part of the hot water bottle which stores the water and keeps it warm for a certain amount of hours.


How to check if your hot water bottle is safe for use (PVC, rubber, and silicone)

Pink hot water bottle

First of all, you must follow the instructions given by the hot water bottle brand you purchased your item from.


The manufacturer will indicate how long you can use your hot water bottle before replacing it. While the life span of a hot water bottle usually ranges between 2 and 3 years from the date of production, some governments and safety consultancies recommend you change your hot water bottle every year to prevent accidents.


Check the date of production

The date of production of your hot water bottle is indicated on a daisy wheel stamp, which you will find on the bottle's body.


Here’s how to read a daisy wheel:

Hot water bottle daisy wheel

1. The sections

Each daisy wheel has a wheel with 12 sections, 1 section for each month. Identify which section has one or more dots in it.


2. The dots

The number of dots in the section (the month), refers to the which week of the month the bottle was produced.

  • 1 dot: first week of the month

  • 2 dots: second week of the month

  • 3 dots: third week of the month

  • 4 dots: fourth week of the month

3. The year

You can identify the year your bottle was produced in look at the number in the centre of the wheel.


Examples:

  • 20: 2020

  • 21: 2021

  • 22: 2022

Remember to follow the manufacturer's instructions when it comes to your hot water bottle's longevity and use the daisy wheel to know how much time you can still use your hot water bottle safely.


Check for leaks before use

Checks your hot water bottle doesn’t have any leaks, especially if your item is past 1 year since the manufacturing date.


To check for leaks, you can:

  • Carefully and slowly squeeze your hot water bottle above your sink to see if any water comes through potential cracks

  • Fill your hot water bottle with air, close the cap, and squeeze the bottle under water: if you see bubbles coming up, you probably have a leak

  • If you even doubt having a leak, change your hot water bottle immediately to prevent any burns.

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