The electric kettle is great because the water is cold and only heats up when I push the button. It then takes less than a minute to become the perfect temp.
But can't be used on shabbos
Thermos works great on shabbos. Also when traveling, keeps the water warm and you can add formula when needed. No need to worry about the bottle spoiling.
The other Shabbos option is to take a little water from the urn and mix it with cold until it's the right temperature.
But the urn is downstairs...
Then use a thermos
Is it an issue of hatmanah?
Not according to Igros Moshe
Thanks! I'm assuming any type of thermos. Just fill it with hot water from my urn before going upstairs and using it regularly?