a heat mat can be found at plant/nursery stores about 12- 15$. the mat is for sprouting seeds, but i keep my cactus on it in the winter, and it works well.

Good point but I tried it several times and it took a long time and the
sugar was not used up. This way it has used up the sugar and
tastes like I think it should (like the KT I purchase in the store.
I'm going to do another test and go and get another KT from the
health food store and start another batch and put it on the stove
(over the pilot light) and see if starting over with the added heat will
give me a better scoby.
Even though my scoby seems to be working I'm not happy wit hthe
way that it looks. I was looking though some website and there
was one site that had a lot of pic's of various scoby that were okay
and mine looked just like one of the pic's It looks more like a
light brown bubbly, not smooth scoby. So we will see if that turns out
Another note. Form the last batch I poured my finished tea in three
cleaned out KT jars added 1 teaspoon freshly grated ginger, 2 teaspoons
sugar and 1 tablespoon of lime juice........That turned out WONDERFUL.
when I opened it up to test it today it fizzed all over the place and is
just that right taste for me.