11 May
2016

Energy Efficient Hot Water Boiler & Warmer

Posted by Norman F

Zojirushi VE Hybrid Water Boiler Warmer

Zojirushi VE Hybrid Water Boiler & Warmer is an energy efficient device that we recently purchased.  We have found it consumes far less power than using a microwave to boil water for beverages, instant noodles, etc.  It is also far handier than boiling water on the stove.

We had a 6 year old model that needed replacement. This unit is Vacuum-insulated to keep water warm. It provides maximum energy efficiency with 195 degree water falling slowly to 150 degrees 8 hours later.

280 to 420 watts of power are used to boil 4 liters (16 cups) of water to 212 degress. A 1000 watt microwave overloads my energy meter, so we could not measure it directly. It takes about 2 minutes to warm up a cup of water and the microwave is about 65% efficient meaning it uses 1500 watts, which equates to 50 watts of power. Electric burners use about 25% less electricity than a microwave in boiling a cup of water. The unit does use energy even in vacuum mode, 0.05 amps according to my Killawatt, so unplug it from the wall to maximize your energy savings.


Most Green ways to boil Water

  1. Electric kettle or boiler powered by solar panels
  2. Electric stove powered by solar panels (70% efficient)
  3. Gas Stove (Only 35% efficient)
  4. Electric kettle or boiler
  5. Electric stove
  6. Microwave

Reboiling Hot Water

Recently, folks have been talking about health problems when reboiling water again and again. In November 2015 this statement went around, primarily from this site:

The reason for this danger is that when water is boiled, its chemical makeup is changed, which initially is a good thing; germs are killed. However, when reboiling occurs the dissolved gases and minerals that have been chemically changed become toxic.  The chemical alterations cause  deleterious health effects from arsenic, nitrates and fluoride. Even minerals that are good for us in smaller amounts, such as calcium salts, can become quite harmful when they amass due to reboiling.  This can lead to kidney stones and gallstones.  Nitrates turn into nitrosamines when ordinary water is reboiled, making them carcinogenic.  Similarly, arsenic becomes more abundant in reboiled water which can result in cancer, heart disease, developmental disorders in children as well as neurological problems.  The same can be said of Fluoride.  Click the video below, for further discussion of why water should never be reboiled.

Ah, social media to the rescue again. Of course there was no proof that this was a problem. Some have said it causes cancer. This is a waste of energy of course. Boiling water kills off germs and microbes. The problem is when you are boiling contaminated water from a dirty source that may contain non volative chemicals such as nitrates (found in fertilizer), and arsenic. Well water may contain these chemicals. If you have a private well in a rural areas, you need to test your water quality. Re-Boiling increases concentration of these chemicals.

Snopes made a page on this urban myth.

If you are concerned, boil only what is necessary and pour out any excess.

How do you boil hot water for coffee or tea?

Posted on May 11th, 2016
If you enjoyed this post, be sure to subscribe to our RSS feed.

2 Responses to “Energy Efficient Hot Water Boiler & Warmer”

  1. Greer Says:

    Any idea how these Zojirushi boilers compare to boiling water on a gas stove, energy and cost-wise?

  2. easy eco blog Says:

    I think the computation is complex because the unit runs all day long, keeping water warm. Compare this to a one shot boil hot water..

Leave a Reply

Please do not put your URL in the comment text and please use your PERSONAL name or initials and not your business name.

By using our site you agree to our: Privacy PolicyTerms of Use.