Circulon Contempo Teakettle 2-Quart Whistling Enamel, Red

It takes me awhile to boil water from a whistling kettle due to water residue build up inside, and my water kettle is getting heavier.

A: In addition to the white vinegar - this also works very well.
Buy some denture cleaning tablets or powder (the ones that fizz when you drop them in warm water)
Either heat the kettle a little or put warm water in and drop some tablets

It's Tea Time, With No Wasted Energy

I like to drink all kinds of tea. Black, green and everything in between—just give me hot water and a little dash of honey and I’m happy.  But I’ve often wondered (as I’m brewing the day’s third or fourth cup) how much extra energy my tea habit consumes. Turns out, I’m not the only one who’s watched a pot boil and wondered the very same thing.

Professors Shi Yuanwu and Wu Chongxiang of Hubei University of Technology’s School of Art and Design, in China, noticed that whether boiling water or making dinner, most of a stove’s heat is lost before it actually reaches the cooking vessel. When a typical gas burner ignites, a large percentage of the heat disperses outward horizontally underneath the stove top, rather than heading up toward the pot or pan. By altering their perception of what a kettle should look like, Yuanwu and Chongxiang were able to create a vessel that would virtually eliminate this energy loss.

Source: EarthTechling

What Exactly are Whistling Tea Kettles

All tea kettles with an open spout are whistling tea kettles though some tea kettles intentionally place some further spout covering or contraption which emits a separate whistling sound. The whistling sound of a tea kettle depends on the size of the opening of the spout and its neck length. In the process of heating water in a kettle, as the water heats, some of it turns into vapor and this vapor must somehow exit or escape from the pot. That is how the whistling tea kettle got its name. Thus you see a bit of that steam and a lot of that hiss in the kettle. As the vapor makes its way to the spout, it produces a hissing sound as it moves from one climatic characteristic to another.

Source: What Exactly are Whistling Tea Kettles