Model # AE-125

Internet # 100094582

Store SKU # 293656

4 GPM 26.85 kW 220/240 Volt Point-of-Use Electric Water Heater

  • Same-day installation in most areas. Call 1-855-400-2552 by noon.



Model # AE-125

Internet # 100094582

Store SKU # 293656

Store SO SKU # 1000895778

Ideal for replacing your electric storage tank water heater, the Bosch/PowerStar WH27/AE125 electric whole house tankless water heater is compact and powerful and can installed virtually anywhere inside the home. Advantages include endless hot water, reduced electricity costs and substantial space savings. Designed to replace a 40-gallon electric tank, the Bosch/PowerStar WH27/AE125 electric tankless water heater is built to last with solid copper heat exchangers, and can help provide homeowners with a lower energy bill.

  • Compact, lightweight whole-house tankless electric water heater
  • Zero standby loss - only heat the water that you need
  • Solid copper heat exchanger
  • Built-in flow sensor ensures constant output temperature
  • External temperature control knob
  • Thermal cut-out for safety - protects elements from damage
  • Can be installed in several locations
  • Also requires 3 separate 40 Amp 2-pole circuit breakers and six #8 AWG wires plus ground, minimum 200 Amp breaker panel (not included)
  • Flow sensor to provide a constant output temperature
  • 220 / 240 Volt - 120AMP
  • Requires 3 double pole 40AMP
  • See model AE-115 for warmer climate applications and requires less AMP's AE125
  • 1/2" water connections

Info & Guides

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Product Depth (in.) 
Product Height (in.) 
Product Width (in.) 
15.25 in 
Water Connection Size (in.) 
Amperage (amps) 
Electric Product Type 
Commercial & Residential 
Finish Family 
Flow Rate @ 35 F Rise (gallons/min) 
Flow Rate @ 45 F Rise (gallons/min) 
Flow Rate @ 55 F Rise (gallons/min) 
Flow Rate @ 65 F Rise (gallons/min) 
Fuel Type 
Maximum Temperature (F) 
Minimum Activation Rate (gpm) 
Minimum Temperature (F) 
Product Weight (lb.) 
11 lb 
Residential/Commercial/industrial Use 
Water Connection Location 
Water Heater Features 
Overheat Protection 
Wattage (watts) 
Warranty / Certifications
Certifications and Listings 
1-UL Listed,CSA Listed 
ENERGY STAR Certified 
Labor Warranty 
No Warranty 
Part Warranty 
1 Year 


Flow Rate @ 45 F Rise (gallons/min): 4 - 4.5
Water Heater Features: Overheat Protection
Review Rating: 3 & Up
Indoor/Outdoor: Indoor


Rated 3.6 out of 5 by 64 reviewers.
Rated 1.0 out of 5.0 by Do not puy this Bosch product. Bosch will not honor the warranty. Their rude phone staff will tell that what ever is burn out or tore up is not under warranty, then tell you what is. Then when that goes out, then that is not under warranty. My new issue is the diffuser just on the inside of the screen has broke, and a shard of it is pinned in the flow sensor, and will not generate hot water. They have told me that this piece of debris came from the water supply and magically made it through the screen. The warranty does not cover debris that comes into the system from the supply. July 22, 2013
Rated 5.0 out of 5.0 by decent product it ran for 5 years without an issue. used it to fill the hot tub several times. amazing on demand; and i have cold well water. then it developed a small leak around the white wires and the bottom of the middle heater. turned green. called bosch, they asked for pictures and i sent them. i received a call back in 15 minutes telling me they were sending a new one to my house. thanx bosch, i'll keep buying your stuff. August 5, 2011
Rated 1.0 out of 5.0 by Less than 1 star We originally had a Bosch AE115 after less than 3 years we replaced it with a Bosch AE125 from Home Depot. The AE125 is no longer functioning after only 9 months. Tried to get someone to fix it and everyone we contact says "we don't work on those anymore". My husband went to Home Depot who called Bosch and Bosch wants an electrician to get on the phone with them to assess the tankless water heater. Home Depot gave us the name of an electrician they recommend but when we called them they also said "we don't repair those". So we still don't have hot water. The electrician said someone would call us back but that was over a week ago. What ever you do don't buy a Bosch Tankless Water Heater. March 10, 2013
Rated 2.0 out of 5.0 by Not in Stock?? The first problem that I encountered when "trying" to purchase this item was, that it was not available in a store. Normally when someone needs to buy a water heater it is an emergency and not being able to get one quickly was a hassle. I also recomend that you put an aproximate cost of additional materials needed, for me it was $160, fortunately I was able to install everything myself or the cost of installation could have been very large. So far the product usage has been questionable, adjustments have been made when using the shower, and sinks in my house. Overall I am not as pleased as I would like to have been with this product. July 12, 2010
Rated 1.0 out of 5.0 by Don't do it!! I purchased this product about 3 years ago and was somewhat happy with it for the first year or so, in spite of uneven water temperatures. Be aware the discharge water temperature will vary as the incoming water temperature or pressure changes. Then things began to fail one at a time after the warranty ran out. First a thermal cutout went bad. It took me two weeks to get one from the factory. (It's a specialty item only sold through Bosch....everything is) Finally the control board failed. I'm tired of working on it and am going back to a standard, old fashioned and reliable hot water tank. To be honest, I really didn't notice much savings in electricity. This unit is just too unreliable to justify the high purchase price and the high installation costs. Invest in more insulation. September 19, 2010
Rated 1.0 out of 5.0 by Expect your water heater to last more than 4 years? Stay away from this brand Installation was fairly easy. Remember to factor in approx $150 for additional parts. Unfortunately the unit doesn't last long. Two major problems when discovered when the unit first stopped producing hot water then developed a major leak. There is no electrical regulator inside the unit. Which means there is nothing to prevent the unit from burning internal parts. Second problem is the reservoirs are PLASTIC. Both of the element assemblers cracked. Question became which occurred first the heat burn out or the cracked assemblies. Neither should occur in a 3.5 year old unit. To top it off, none of the local HD contractors work on the unit, which was installed they an HD contractor. Finally found someone who works on them but since they didn't install it, they want no parts of it. They were nice enough not to charge for consultation and they were able to give me info to contact the manufacturer. Had to call the company to find someone authorized to make repairs. Bottom line is its more cost effective to replace the unit. With a different company. December 29, 2014
Rated 4.0 out of 5.0 by The upgraded AE125 works great! I had the older model AE125 but It wasn't that reliable- at least twice a year I would have an issue. It developed a leak and Bosch replaced it free of charge and the new unit was an upgraded ae125- different circuit board inside. This new AE125 has not missed a beat! This replacement was over four years ago no problems whatsoever. Very pleased with the ae-125 it will not disappoint! November 12, 2015
Rated 5.0 out of 5.0 by James Schinault I really like the whole house hot water heater. I am on well water and didn't know if it would heat 66 degree inlet water temp but it will. I turned the easy access temp. control down one third of the way and still have plenty of hot water for showers, dish washer, baths and washing machine. I installed a ball valve on inlet and outlet side of water heater which allows me to control flow of water which stopes any to hot and to cold water flow being on a electric pump 25 to 50 pound pressure and it workes great. Unit was easy to install. Takes up almost no space in utility room. I haven't used it enough yet to tell if it saves me on electricity yet. But I am sure it will. We don't run out of hot water. May 13, 2006
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