I'm looking for a kettle or a dispenser that can keep or warm up the water around 100 F. The hope is to drink the warm water directly. All the devices I've found so far are made for boiling the water for making Tea, etc. I could get a dispenser, mix hot and cold water. However, I'd need to be careful every single time to mix them in the right proportion; just hoping to avoid any risk.


I was hoping to find a make-human-lazy sort of tool for this but didn't succeed. Thanks for all the answers. I'm going to use the good old stove for warming up and a vacuum flask to store them. I might consider something like this in the future - https://www.amazon.com/dp/B01N4WYPDX?ref_=pe_623860_70668690 .

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    Luke warm water is a very good source for bacteria to develop. Legionnaires disease is a primary example. I suspect that is why they don't sell them. Thus if you have a solution make sure you regularly refresh the water and disinfectant whatever-it-is-keeping-it-lukewarm
    – Oldfart
    Commented Dec 9, 2017 at 21:52

7 Answers 7


The easiest tool I can think of is a thermos - fill it with water at or slightly above your desired temperature and enjoy your supply for a few hours.

On a larger scale, a tankless heater can give you a basically unlimited supply of water, but is almost certainly overkill.

Please be careful with all devices that keep water at around 100F / 37C, this lukewarm water will encourage the growth of microorganisms, aka a biofilm. This is also an issue with all water dispensers / coolers, which should also be cleaned regularly.


Why don't you grab a bottle warmer for baby food? Smaller quantities, but you can set the temperature just fine.


There are kettles on the market which have an adjustable electronic thermostat, some of them allowing very low temperature settings. Example (review article of some such kettles, some of them appropriate for the task): http://www.independent.co.uk/extras/indybest/food-drink/best-variable-temperature-kettles-adjustable-electric-glass-no-plastic-2016-tea-a7179216.html.


Mixing boiling and cold water is very feasible. Two parts cold to one part boiling will give about the temperature you want. I use this method for the rapid bake program in the breadmaker, which expects water at an optimal temperature for yeast (actually slightly higher as the flour is at room temperature). For breadmaking I measure by volume, but for drinking you can do it by eye in a glass. There's no risk in this method: if it turns out too cold, at a drop more hot, and if it turns out too warm, wait a moment or add a drop of cold.

An alternative is to work out how long you need to heat a glass of water in a microwave from cold. Try 30s to start with. It will need a stir afterwards.

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    I have a hot water dispenser (for tea, so it's kept at less than boiling) and I've found half and half or up to two parts hot to one cold, works for me. The point being that one can take advantage of whatever's easiest to hand. Additionally, if you use the same/similar cup or mug, it's pretty easy to figure out the exact proportions by eyeballing the measurements after a few times, so it isn't that much extra effort - just dispense hot, one step to the sink, top with cold. Quite possibly less than finding and adjusting some other solution to keep the water at your preferred temp.
    – Megha
    Commented Dec 13, 2017 at 1:14

An alternative is to put a thermostatic mixing valve below your sink and add a warm water tap.

A thermostatic mixing valve accepts cold and hot water inputs, and can be set to output a set temperature. It automatically adjusts the ratio so the output is the set temperature.

The valve is inexpensive, and combined with a single valve faucet above the sink would fulfill your needs without requiring cords and appliances on the counter.


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    Not recommended!: "Never Drink Hot Water From the Tap (or hot mixed with cold). The claim has the ring of a myth. But environmental scientists say it is real. The reason is that hot water dissolves contaminants more quickly than cold water". nytimes.com/2008/01/29/health/29real.html -- From the CDC: "In all situations, drink or cook only with water that comes out of the tap cold ..." cdc.gov/nceh/lead/tips/water.htm, -- From the EPA: "Only Use Cold Water for Consumption ...". cooking.stackexchange.com/questions/21471/… Commented Dec 11, 2017 at 0:29
  • In addition, where I live, the tap water is decent but it's better to filter. The majority of filters don't handle hot water.
    – phanin
    Commented Dec 12, 2017 at 18:58
  • Be aware of legionnaire's disease risks when building any such contraption - potentially standing warm water and hard to clean inside spaces, bad combination. Commented Dec 12, 2017 at 20:45
  • @rackandboneman Yes, if this is done it must be with pipes as short as possible, which is why I suggested it right under the sink. Just like with hot water you're going to run it for a bit to get the warm water out, ejecting any cold water and providing only freshly mixed water.
    – Adam Davis
    Commented Dec 13, 2017 at 15:47

There are devices for keeping coffee or tea warm at your desk called mug warmer. If you only want to keep a single mug worth of water warm, I think it will work well. I have linked one that has a temp you can set.


There are three things come to mind. Point of use water heaters. For a shower or tap. Set the temp. turn on the switch, turn on the tap. electric. Or water heaters for pets. Set the temp. hold water at a high of about 100f. Found in pet stores. For 2 1/2 gal. or 5 gal. Set on counter. Building supply stores or the pet shop. I see them in Asia under baby needs. Were women want warm water for a child on hand. But look on line there for one. May not be in America. Most of Asia is 220v so may not work in America.

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