I use an electric pot that I can unplug and replug into my living room
or dining room or whatever room. You can also use one of those
Japanese water boilers that keeps water at an even temperature (see,
e.g., http://www.veryasia.com/thermo-pot.html, but note that this is
just a random link to show you the machine--you'd be best to check
around the web for prices and such). Both of the above methods require
you to plug something in. Those two electric methods are the only ones
I've tried. I can leave others to say the value of gas or alcohol
burners.

cha bing