Does such a hot water dispenser heat water by itself? https://www.grainger.com/product/IN-SINK-ERATOR-0-7-gal-Hot-Water-Dispenser-23NU44. I saw one that looks like the one in the link was installed near a regular tap water faucet. I am not sure how it gets water, if it heats the water by itself, and whether it makes water more clean or safer to drink than tap water. Thanks.

enter image description here

  • It probably tees off one of the water lines and heats the hot water to very hot(boiling temps). Does not seem to have a water filter. Do to the high water temperatures it would be dangerous for kids/people not careful. It will burn skin, not good for washing hands.
    – crip659
    May 8 at 22:04
  • Same tap-water, more electricity wasted keeping a relatively-less-well-insulated container (.vs standard water heater) scalding hot all the time. More efficient to put a mug of water in the microwave or use a kettle only when you actually need scalding hot water (for tea, etc.), but you might have to wait a whole minute or two...they fail regularly from mineral buildup (and have no practical means of cleaning that out) from what I've seen in places that installed them.
    – Ecnerwal
    May 8 at 22:16
  • If you're in the first world and worried about water safety, that's usually about chlorides, chloramines and fluoride put in the water to kill bugs in it. For that you need filters, which can be gotten that attach to a tap like this. May 9 at 3:15
  • There are various installation configurations that can minimize or eliminate mineral contamination: An ordinary inline filter with a filtering element that you'll have to change every couple of years, or an RO filter (we use it to eliminate the salt after our water goes thru the water softener). Regarding energy efficiency that @Ecnerwal mentioned... the one I have is fairly well insulated and saves running the hot water tap until it gets hot, saving both water and the energy required to heat it. ....continued below....posting this as an comment bc it's not really an answer. ..... May 9 at 14:08
  • I find the instant hot water dispenser EXTREMELY convenient and if it costs me a few dimes a month in power, I'm fine with that. Also, you have to consider the delta change between using a micro wave or kettle vs. the instant hot. Those also take energy. Next: When you are fixing breakfast for 3 kids and they all want hot chocolate and the wife wants her tea, the instant hot is great. It would take quite a bit of time in the microwave to heat up 4 cups of water. I'm willing to pay just a bit extra to make my life easier. May 9 at 14:15

2 Answers 2


This type of device has a small storage tank. It heats water in the tank to around 200 F. Where a typical whole house water heater has 30 to 50 gallons, this has a 0.7 gallon tank under the sink. Because it is at point of use, it is "instant". But to keep installation costs low, it has limited capacity. Perfect for quick hot water for a beverage and that's the main use. Not a substitute for hot water to wash the dishes. Too hot to wash your hands.


The makers website has a photo that includes the under-bench component that heats the water.


enter image description here

Usually when water needs to be boiled to make it safe you should actually boil it, this device only almost boils it.

A filter is probably a better way to make water safe.

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