A bottle that keeps water hot is called a thermos, vacuum flask, thermosteel, or insulated bottle — all the same technology (double-wall stainless steel with vacuum between the walls). "Thermos" is originally a brand name that became generic; "vacuum flask" is the technical term; "thermosteel" is Milton’s brand-popularised name in India. Quality vacuum insulated bottles hold hot for ~12 hours and cold for ~24 hours.
Key Facts
- Same technology, different names: thermos, vacuum flask, thermosteel, insulated bottle.
- Double-wall steel construction with vacuum between the walls.
- Retention: hot ~12 hours, cold ~24 hours.
- HYV uses food-grade 304 stainless steel with double-wall vacuum insulation for verified hot/cold retention.
The names explained
- Thermos — originally a brand (1904), now genericised for any vacuum flask.
- Vacuum flask — the technical term.
- Thermosteel — Milton’s brand-popularised name in India.
- Insulated bottle — generic modern term.
What they all describe
Double-wall stainless steel construction with vacuum sealed between the walls. Heat cannot cross the vacuum, so hot stays hot, cold stays cold.
How long does one keep hot?
~12 hours on quality BIS-certified SKUs. Depends on fill level and lid seal.
Frequently Asked Questions
What is a bottle that keeps water hot called?
A thermos, vacuum flask, thermosteel, or insulated bottle — all the same double-wall vacuum steel technology.
Is thermos and vacuum flask the same?
Yes — same technology. "Thermos" was originally a brand; "vacuum flask" is the technical term.
Leave a comment
This site is protected by hCaptcha and the hCaptcha Privacy Policy and Terms of Service apply.