Frugal and Energy Efficient Living

I don't know what to say about the options you are asking about. I never even knew that this existed, or that there were electric water kettles.

From what it says about this water boiler, it sounds like it has to be on and keeping the water heated all the time. I doubt that either of the appliances use enough electricity to be a significant factor, but I could be wrong. In the comments from the link:

"Based on the manual the keep warm mode takes from 11W-20W per hour for the 4L version depending on the keep warm temperature. The 5L version takes about 14W-26W per hour depending on keep warm temperature. When the unit is boiling / reboiling it consumes 840W per hour, however it takes about 35-40 minutes to boil the water from room temperature to full boil.
For example: We have the 4L version and we fill it once a day and set it at 175 degrees and allow it to go to a full boil. The approximate power usage is (12W * 24 hours + 840W * 0.58 hours) = ~780W for the entire day (i.e. less than 1KW per day or approximately 24KW for the month). For us 1KW is about 12 cents, so it cost less than $3 per month for us to operate."

How does that stack up to your water kettle? I have a gas range, so that is how I heat water for tea. It is quick and easy and can be done in any receptacle I have at hand. Even when I have only electric range, it took little time to get water to boiling, although I don't know the electric usage (that was a long time ago).