PowerStar AE-12 Electric Tankless Under Sink Water Heater

I have this "point of use" hot water heater connected to a dedicated cold water line for the dishwasher and kitchen sink. It's located in the basement directly under them and gives me hot water in about 3 seconds, the time it takes to travel up to the sink. It used to take 90 seconds to get hot water because of the distance from the regular hot water heater. I'm very happy with it. Another great product by Bosch!

I've just finished installing and testing my second AE-12 water heater, this one replacing one that died after working reliably for ~8 years. The original started having problems where the internal thermal cut-off safety switch would be tripped after each use. From what we could tell, the heater wasn't shutting itself off when the water flow stopped, so the water in the pipes would overheat and trigger the cut-off. Because we were already wired and set up for this model, we decided to buy a new one despite the negative reviews. We got it wired in and it seems to be working well.We use the AE-12 as an under-sink heater in our kitchen. Although we live in California, our pipes run through a concrete slab between the main hot water heater in the garage to the sink. With the long run thru cold concrete, we just couldn't get truly hot water to the kitchen. The AE-12 solved our problem -- we have hot water within 10 seconds of turning on the tap and have been very happy with its performance over the years. Of course, getting and electrician to run a 240V/50A circuit was way more expensive than the water heater itself, but well worth it in the end.One point of caution: be sure to turn the heater control all the way down when starting to use this and then turn it up in small increments until you find the setting that works for you. If you turn it up too high, we found that after shutting off the water, the residual heat in the device would cause the water remaining in the device to boil (you could hear it bubble). Just as with our original device, this would cause the thermal cut-off to be tripped and require a reset. The boiling water would also release air into the pipe, so the next time you started water flowing thru it again, you'd get a big air burst mixed with boiling hot water from the faucet. After learning our lesson, we turned the heat all the way down and then back up until we found our sweet spot.I'll plan to re-post if anything goes wrong with the device, but given our previous one lasted 8 years and this one appears identical, I'll be happy if we can get another 8 out of this one.

The only reason I purchased this last one is because all my plumbing and electrical fittings are set up for this unit. I won't get another. This unit was originally manufactured by a British company (with a 10-year warranty) which has since been bought out by Bosch. I special ordered the first one about 8 years ago from Home Depot and had a plumber install it because the warranty dictated it. I had already changed the plumbing and run the electrical so all he had to do was actually install the unit, which kept my costs down. There are only 2 of us and we live in Florida so we use it as a whole house water heater and have never had a problem in that respect. We love never running out of hot water and the space gained in the garage by eliminating a tank heater. BUT we had problems with the first one within months of getting it. I called the company in Vermont directly and they swapped out units with no problem--I don't know why it stopped working. That unit lasted a little over 3 years and I could see a burnt spot by a transistor. That time they just sent me a new one at absolutely no charge to me and didn't ask for the old one back. I believe they had changed the warranty to 5 years by then. That unit also lasted a little over 3 years but by then Bosch had taken over and when I called they wanted me to have both a plumber and electrician verify that it had a problem and I hadn't caused it. Obviously that would have cost me more than a new unit. So I just ordered one through Amazon in case it had a problem right off the bat because people said Amazon took returns without any hassles. The one smart thing I did do was install unions when I orginally set up the plumbing. Since then I've swapped them out myself with no soldering. As long I have two non-working units now I may contact the nearest repair facility and see what repairs might cost. As I've said, I love the tankless aspect and will never go back to a tank, but I will never buy a Bosch product of any kind again.

When it works it is great, hot innstant water. first unit last maybe 2 years , the 2nd maybe a year.both times the water got less hot. would expect more life for a $200+ unit. Others are less expensive.wasy to install as it only requires a 1/2 faucet line not any compression fitting.would not recommned due to durability