Thought I would roll over to my 2,000th post with a question- or at least an observation... So after a few years of looking at the box on the storage shelf, 'Install In-sink-erator Instant Hot Water Tank at Kitchen Sink" finally rolled to the top of the honey-do list. Luckily, I was planning ahead when I re-did the kitchen, so all the electrical and other fittings were in place and it was basically a plug-n-play affair. Now kicking myself because it's sooo convenient! The downside is about every 15-20 minutes, the thing lights off with that 'almost but not quite boiling' RUMBLE!! It's loud enough to hear through the whole house, has woken me up from sleep a time or two, and you actually have to raise your voice a bit if you're in the kitchen when it erupts. I know this is the water in the local area of the heating coils just starting to boil. They recommend a temp of 190ºF, I'm just a bit less, but still not that hard to get localized boiling. I tried a bit lower temp, but by the time the water is out the tap and into the mug, and warms the mug, the water isn't hot any more. But the big questions are - do people just 'put up' with this rumbling? is this possibly a defective unit? anybody successfully 'silenced' a rumbling heater? I know our water heater/cooler at work doesn't rumble like this, though it's the style where you invert a 5 gallon carboy on top. So it's possible to make hot water without the rumble. I suspect the key is to have either a low power heating unit, or some way to reduce the power input as the water gets hotter.