Did you know that how long a hot water bottle [hwb] will stay warm for depends on various product factors and the surrounding environment the hwb is being used in; for example if you are sitting outside your hwb will not keep warm for as long compared with if you were sitting inside a warm room under blankets!
Having supplied [and used!] hwbs for nearly 50 years we are able to explain the factors affecting how long your hwb stays warm!
Product factors that will affect how long your hot water bottle will stay warm for:
1. The percentage of rubber the hwb is made from: rubber is a good insulator of heat. At THWBCo. all our hwbs contain 55% natural rubber which is the highest amount of rubber which can be used in production - the percentage of rubber used in hwbs can vary from brand to brand. Read more about how rubber content in a hwb can affect the quality of a HWB here.
2. How thick the walls of your hwb are. All hwbs should meet a minimum standard of 1.4mm for wall thickness to comply with the voluntary British Standard 1970:2012. Our hwbs have a minimum wall thickness of 1.6mm. it might not be much but everything counts!
3. The style of hwb: Is is plain sided, ribbed on one side or both. Ribs on a hwb help trap heat and keep the hwb warmer for longer, therefore a hwb that is ribbed on both sides will keep warmer for longer than a plain sided hwb.
4. The style of cover used. How thick your cover is, the quality and type of the material will all affect how long your hwb stays warm.
Environmental factors that will affect how long your hot water bottle will stay warm for:
1. the temperature of the water used
2. how much water is being used to fill the hwb
3. The surrounding environment: outside or inside, is the room cold or warm, is the hwb being used with or without a cover, is the hwb being used under covers?
As there are so many variables it is very difficult to say how long an individual's hot water bottle will stay warm for but it is very possible that a hwb can stay warm for 8 hours or longer if the product and environmental factors help this to happen!