Bosch AquaStar 125B NG Natural Gas Tankless Water Heater

Pros: Good for the environment, save energy, no standby losses, compact.
Cons: Often don't meet high water demands of North Americans, need maintenance plans factored in.

Tankless, gas-fired, instantaneous water heaters have been trying to break into the North American markets since the late 1970's and early 1980's. It therefore isn't "new" technology, as countries like England, Germany, and Japan have all been ...

Pros: Space and energy savings in the long run.
Cons: Installation hard, won't notice any savings right away, can't to many things at once.

When I moved into my house over a year ago the first thing that I had to do was replace all of the plumbing. Then I noticed that I needed a new water heater. We originally had a 40 gallon heater. I really would like to have a 50 gallon one. I shopped ...

Pros: Takes up next to no space, endless hot water
Cons: A bit difficult to install yourself

Here’s the scenario: One Sunday morning, I took my usual shower and noticed the water was tepid, not hot like I prefer. As I got ready to leave the house, I mentioned to DH that either The Child had run us out of hot water (yet again) when he took ...

Pros: Inexpensive for a gas tankless. Works well. Saves space.
Cons: Pilot light instead of electric start. A lot of work to install. Require maintenance.

After 11 years, my 50gal gas water heater started leaking. I shopped around for alternatives, and decided that tankless was too expensive. I was at Lowe's to buy a new tank for $338, when I saw the Bosch 125B on clearance for $369. It's normally $499, ...

Pros: Pros: Endless (but limited volume of) hot water, smaller than tank.
Cons: Cons: Temperature surges, expensive, maintenance

Note: I don’t own this hot water heater, but I own a similar one. The comments I make here apply to all tankless heaters, regardless of brand. These are things you should consider before making a purchase. They are also things you won’t hear from the ...

Pros: Constant hot water if you like to be scalded.
Cons: Demands consistent cold supply water

At first we thought "what a great idea... saving money and energy", but the cons out weight the pros of this unit. We bought the Bosch Aquastar 125BNG tankless water heater from Home Depot to replace our still running 21 year old 40 gallon water heater. ...

Pros: It saves space. It's cheaper than any other tankless heaters I've seen. It's energy efficient.
Cons: Difficult installation. Temperature varies. Faucet must be fully on to operate (no hot water trickle).

The following review was my initial opinion of the Aquastar 125B. I have updated the title and pros/cons to better suit my current opinion but I'll leave the review alone because I think it helps illustrate how this heater can take some dialing in and ...

Pros: Continuous hot water, Small and compact
Cons: May have to replace some pipes due to requirements, Takes awhile to get hot water

When I first purchased my house everything needed to be replaced. Down in the crawl space among more important things that didn't work was an old (very old) waterheater still in somewhat useable condition. And there it sat up until about 10 months ago. ...

Pros: Smallest hot water heater, unlimited hot water, runs two showers at once.
Cons: Cost, Maintenance and Installation

I like this thing. Sure it's expensive, requires maintenance and was a real challenge to install, but it saved a ton of space. I now have a hot water heater, microwave, dishwasher, a little counter space and 3 shelves in the same space that used to ...

Pros: Energy savings, space savings, continuous hot water on demand, long life, earthquake safe.
Cons: I had one service call during the last eight years.

I have used a Bosch Aquastar 125 in my home serving a family of four for more than 8 years. This water heater works like a spa water heater by heating water as it senses water passing through a heating chamber. It is "on" only while the water is ...

Pros: tankless
Cons: 2 holes to the outside, quality is poor, size, breaks often.

had it for quite some time and would not buy it again. Too little for more than 1 bedroom house, breaks often, repairs and replacement parts are not so easy to find and expensive. when installing have to make 2 holes to the outside because it needs to ...

Pros: Absolutely NONE
Cons: Expensive, wastes water, no tech support, EXPENSIVE to call plumbers who know NOTHING

I just built my "dream home of a lifetime" - Chattahoochee Riverfront in the North Georgia Mountains. We wanted our home to be top quality, state-of-the-art. We did research (Not as much as we SHOULD have, turned out) and bought the Bosch Tankless ...

Pros: good for cottages, one person house holds, for spatially challenged areas.
Cons: Horrible: Output GPM, COST of Unit, installation, maintenance.

I've installed one in my home also. At first I was satisfied, but now I have grown annoyed with the heater. No one else in the household can use the hot water while you’re in the shower, or else you will get doused with cold water. Also, it takes ...

Pros: Endless hot water.
Cons: Hard to control temperature + other high costs.

I have had this unit for about 6 years. I was happy once I go over the installation and it was all said and done. We did enjoy not running out of ho water but there are some huge trade offs. You will immediately notice that you cannot control the amount ...

Pros: Lowest cost in it's class. Hmmm it's the only one in it's class...
Cons: . If you like Russian autos, you'll love this.

Having installed tankless for decades my experience says use this for one fixture at a time and do your homework before purchasing any tankless. If you do not feel you can service this, do not purchase it. In hard water after a few years of no service, ...

Pros: Available at Lowes for a good price
Cons: Bosch said I should PAY a plumber to repair new heater!

My first Bosh water heater I bought from Lowes. I paid $150 to have it installed and we were not able to get it lit. After it would not light I called Bosch they wanted me to pay for a plumber to come out and repair it.I asked the operator if they would ...

Pros: hot water all the time
no tank so you have extra storage space
hangs on the wall
Cons:  maintennance is high-quality of plastic parts and glues are questionable-expensive parts

this unit is less than 4 years old - every year for 4 years  the carbon builds up so it has to be regularly cleaned in order so that it can  ignite -On a second visit the plumber decided to give me his steel cleaner and he showed me ...

Pros: All fixtures are low flow we can run two showers simultaneously with no problem.
Cons: WARNING: Check CEC web site required maintenance every 2-5 years. High maintenance cost!!!!

Had this product installed in a new house when built. Cost was a little higher than conventional hot water heater, but I believed that they would be outweighed by the long term benefits. Having been stationed in Germany for seven years, I had a lot of ...

Pros: space saver, illusion of continuous hot water
Cons: cost, high maint., poor performance, horrible service, low water pressure.

The 125 has a plastic water valve, replacement part is $150 for another piece of plastic. Mine exploded less than 3 years after installation, but after the 2 yr warranty on parts had expired. The box gloats of a 15 yr. warranty if professionally ...

Pros: none
Cons: EVERYTHING! wastes water, won't stay lit, unethical tech support behavior

Since the purchase of this faulty water heater, it has never worked right and has been a persistent problem. It can shut off 3 times during a single shower, or the pilot light may extinguish when not even in use. For years I have been on the phone ...

Pros: small size, no pilot light
Cons: water not HOT, no service, and too expensive for a boat anchor, probably floats.

I have a Bosch AuqaStar and installed it to save money and "do the right thing energy-wise". What a mistake. I could have bought at least conventional water heater for what I paid for the tankless. I could live with that if it was a money saver. It ...

Pros: you have Pro & has done 5 installs/give him your info-he'll know.
Cons: No Pro you're taking chances. if it was your wifes suggestion, you might have chance.

My experience was in my own home. I could hardly wait for my water heater to go out... my 40gal. track-house unit lasted 18yrs. I purchased mine from home-depot, and bought the highest output rated unit they had. My problem was wife and Daughter.. It ...

Pros: I am sure that many people are very blessed by Televangelists and can afford them.
Cons: Televangilists should tell thier people as to why they are doing what they are doing.

Why do Evangelists have to go on television ?, are they really seeking after lost souls?, are they seeking those who are home bound ?, or are they seeking your money ? How many people do you think actually watch these shows with their Bibles in hand ...

Pros: No wait between showers/baths.
Trouble-free operation
Less expensive to operate.
Cons: Can be more expensive start taking REALLY LONG showers.

This unit was a bit of a pain to install because of the larger vent requirement, but wasn't a major issue.

I have owned this water heater for 9 years, and have never had any trouble with it. I do have to adjust the temperature twice a year, once in the heat of the summer, and then again with it gets cold in the winter. That takes all of 15 seconds to open the closet door and turn the know 1/2 turn, and close the closet door.

This water heater is operating under severe water quality conditions that would destroy a standard storage tank water heater very quickly. If you don't drain the sludge from the tank at least twice a year, it accumulates enough hard water deposits that it starts to make all kinds of strange noises. I'll trade tweaking the temperature setting for that task any time.

Pros: none..does take less space
Cons: read above

Customer service is horrible for one..Takes forever to get tech support...They battery on the phone runs down or the lunch hr is used up..
The product is lousy for another..the housing around the control panel cracked and water was seeping out causing more damage..Most disturbing besides poor service, every contractor and plumber I spoke with had nothing but negative reports. Even the previous dealer Home Depot..He said people were always complaining..I understand why..So I am now out the money after only three years..
Buy a REAM..They do stand behind their product and will not give you the run around. They replace the whole unit if there is a problem within the warranty..Always ask a plumber and contractor for a suggested product and most of all check on the quality of customer service...I paid a big price to learn this.

Pros: Never a problem other than that.
Cons: Heat exchanger replacement costs $250.00 or silver solder repair $60.00.

Owned for 10 years--only bursts in winter.  Used double wall vent pipe,  six foot horizontal run before exterior wall penetration and vertical run six foot outside.  Return line burst three times in past in same location.  Is it cold transfer thru vent pipe or scale buildup the problem?  I have strong calcium in my well water.

Pros: space saver
Cons: tempermental, doesnt work holidays or weekends. tech support sucks

what a mistake, a $1,000.0 plus mistake. i installed this 7 months ago. the first week is made a loud whislting noise through the vent the whole neighborhood could hear. I called the tech line, waited on the phone for 1 hour. he told me to make an adjustment which took care of the problem for about 3 months when it started making a different noise. waited on the phone with a tech for another hour to have him tell me to call gas tech. Gas tech came and knew nothing about the unit, but it stopped making noise on its own. today is xmas eve and the thing took the holidays off. NO HOT WATER PERIOD. I am removing the thing today and will run it over with my truck several times so it fits in the garbage can and put the tank back in. if your considering this please reasearch and save yourself $$$$$$$$$ by avoiding this thing like the plague.

Pros: Endless hot water. Energy savings. Takes up almost no space.
Cons: Somewhat more complicated than your ordinary tank heater.

After replacing an old conventional water heater, we have depended on the Bosch 125B for over one year.
Like with all technical products it is important to understand how they work.
It is fair to say that a tankless heater is more complicated than one with a tank, and in some areas it does not work as well.
For instance, the tankless heater will not allow a very low flow of hot water, as it will shut the gas off.
Other than that I can only think of benefits.
We love it, and my reason for writing this review is to counter all the negative reviews on this site.
I just purchased a new home, and the first thing to go in is going to be a Bosch tankless!

Pros: None
Cons: Too many to mention here.

Tankless water heaters should be avoided like the plague. Any gas savings will be offset by enormously increased water bills. In addition, you get to stand around at the sink or shower waiting for the water to heat up -- what used to take seconds in our house now takes minutes. Expect to buy new shower fixtures to accommodate these pieces of junk as well. Oh, and a new gas meter and 1 inch gas feeder pipe if you don't already have that.

Crap. Total crap.

Pros: limitless hot water, silent, saves energy, compact
Cons: handheld showers can go cold if the pressure isn't constant

We got our tankless hot water heater about two years ago primarily to do our bit to help the environment by cutting down on energy use. We have been happy with it so far with no problems. It does indeed give limitless hot water although sometimes the water will go cold in a low flow situation like a handheld shower which requires you to turn off the water and then turn it back on. We have had no problems with temperature fluctuation or problems with the pilot light that others reported. We do turn the temp up a bit in the fall and winter to handle the colder water temperature coming into the house. I love being able to take a hot bath directly after the washer fills with hot water. It is also silent unlike the old water heater that you could hear turn on and off and that would make alarming noises towards the end of its life because of deposits inside the tank. You can definitely see a difference in our gas bill thanks to this water heater. It saves a considerable amount of money. I recommend getting one.

Pros: Compact size, delivers continous flow of hot water when working.
Cons: High maintainence, energy factor of the 125b is the same as well-insulated tank.

Installed a 125b 3.5 years ago. I choose tankless due to the need to install a unit in a small space and the potential energy savings. The unit generally works well but the pilot light goes out about 3 times a year with the need to clean the pilot oriface with compressed air. Last week the main burner continued running after hot water was turned off resulting in hot water and steam blowing out the pressure relief valve until the gas was turned off to the unit. I ordered the rebuild kit and the unit works again. Woudn't recommend this heater based upon the need to rebuild the water valve every few years. Unless you are a DIY person you will bleed $$$ hiring a plumber. To realize real energy savings go with a pilotless tankless unit. The energy factor is .80-.84 versus the .65 that is realized from a pilot model. In fact a well insulated tank water heater has an energy factor of .65-the same as the 125b! So there is no energy savings with a 125b, just higher initial cost and continued maintainence-opps. Go to www.aceee.org for a list of the most efficient tank models.

Pros: endless hot water.
Cons: less flow and one shower a time.

I had this water heater for 10 years. The reason I got this water heater is that I am not strong enough to handle 50 gallon water tank. My son helped me remove the old tank and still dented on the garage floor.  Took me couple hours to install myself, well worth it. I don't have any problems with this water heater the only changes we have to made is we learn to take one shower a time or fill one bath tub then have another people take a shower. It works out well. I am planning to add an air handler for future project to replace original hot air furnace. Pay back time, with my free labor (my wife always said) $300 more than the tank heater (we pay $500 or so at home depot)seems to be short. Most important, I don't have to wait for hot water any more.

Pros: saves lots of energy when you can only take a 3 minute warm shower
Cons: Sometimes I need more than 3 minutes of warm water, replace old gas lines

I have seen similar reviews from people who have had the same experience as me. The water starts cold, warms up, then becomes scalding hot (without me changing from the "warm" setting), and when I try to put it back to warm, it shuts off all hot water. I've been dealing with this for a month. I get about 3 minutes of warm, tolerable water. Now I shampoo and condition my hair before getting in. It's the biggest pain in the butt of my new condo (June).

And my seller has agreed to fix it (mid-July), but plumbers, people from ComEd all say that it is Bosch's problem. Unfortunately, Bosch is completely unresponsive. After 1 month of constant harassing on my end, they finally sent an email saying to turn the temperature down. It didn't work. I'm sitting in my bath towel right now and am very unhappy.

If anyone can help with this problem, please publish a comment here. Thank you!

UPDATE:
On fourth visit from gas company (end of August), they determined that our gas line doesn't allow sufficient gas to go through. gas company can't replace lines until October. F-this whole eco-friendly money saving venture.

Pros: Endless hot water; space saving; reliable.
Cons: Must not flush toilet/fill washer while someone is showering - reduces cold water pressure.

I had this water heater (then made by e.l.m.) installed early in 1995. I had it professionally installed as I did not even have a gas outlet or flue in the room. It has been worth it's weight in gold; we have showered by candlelight when the power was out; have had numerous people shower one behind the other when we have house guests; done load after load of laundry - all without worrying about running out of hot water. I would have hot water radiators too if not for the logistics of running the pipes with a concrete slab floor!

Every few years we do have to do some maintenance; Controlled Energy Corp. have been really helpful both on the phone troubleshooting and in sending Bulletins telling how to troubleshoot and perform maintenance. We have done all work ourselves with no real difficulties. Once the unit is in place the gas line is not opened. Work is only performed on the water lines and heating coils.

I recommend this type of water heater to anyone that will listen. I have never for one moment regretted paying out the money to have this unit installed.

Pros: Takes up little space, can't shower and run water in other areas at same time.
Cons: Terrible customer service, hardly any licensed repairmen, expensive.

We've had our Bosch for just under 3 years and it worked fine until the last six months. Suddenly the hot water is only intermittent. My husband, who is a licensed plumber, installed the unit and called customer service to get advice on what might be the problem. As the previous person states, customer service was horrible. The service rep. was extremely rude, treated him as if he did not know what he was talking about and refused to help him unless he took pictures of the unit and how it was installed and sent them to her. After checking nearly every part himself with no success, we tried to get someone to service it at our home and discovered there were only 2 repair shops within 30 miles listed as licensed repair for this item. If it hadn't been so expensive, I'd consider replacing it, but at over $700, it should not need replacing after just 3 years.

Pros: Provides all the hot water I need,energy efficient and space saving.
Cons: Installation is time consuming.

I purchased a 110 gallon therapy tub and my 40 gallon heater just didn't cut it. The recovery time took almost 2 hours to fill at a 108 deg temp. After installing the 125B I filled the tub with 110 deg water in 40 min. The installation was harder and longer than I expected and the hot supply flow was cut back but it doesn't seem to effect my shower or washing machine. Thanks to the other reviews I replaced the two set screws on the water valve with stainless. I am very happy with this product so far.

Pros: Energy efficient. Never run out of hot water!
Cons: Sensitive to water pressure--turning on too much cold water and the heater shuts off.

I have had my AquaStar 125B for 3 years. I bought it mainly to save space as my 30 gallon was blocking part of the door into my utility room. I had it professionally installed but even this was a difficult and lengthy process. The installer had to redirect both the gas and water pipes and had to order special vent ducts (but that was not the water heater's fault, but the odd size chimney in my condo).

I have never run out of hot water since! Especially nice in the winter! It's a wonderful, care-free device that has saved me space and money. My only complaint is that the water is almost too hot in the summer--with the heater set at its lowest. Turning on cold water to compensate is sometimes difficult. Too much cold, and the water heater will shut off.

Over all, it's been a good experience and I'd buy one again.

Pros: size (NO bulky tank), endless hot water even with power outage, low bills, low maintenance
Cons: short duration of decreased water flow if another appliance/person uses at same time

Have had the unit for 6 plus years in our vacation house we use every other weekend. I LOVE IT!
PROS:
--No more fear of using up all the hot water when someone is taking a bath behind you.
--Hot water even if the electric power goes out!
--The first month we put the unit in our gas bill went down so low we were just charged a maintanence fee.
--6 plus years and all I have had to do is replace the batteries on the ignition a few times.
--Extremely compact size and no worries that the bottom will rust out and flood my house. The unit hangs on the wall and I am able to use the space for other things!
CONS:
--If someone else or another appliance runs in the house, the water flow goes down for a short duration of time. How long does it take for your toilet to fill with water? The duration is so short it far outweighs all the positives.

Pros: Space saving and saves energy. No electricity required.
Cons: Costs more than a tank water heater.

Endless hot water in the shower / bath and I was surprised how much money it saves me. I switched from an electric hot water heater with a tank and I am saving about 30% on the energy. This is a reliable unit. I have it installed in a pumphouse with well water that gets pretty cold but the hot water still gets nice and HOT. I like that the unit does not require electricity.

Pros: Lots of HOT WATER
Cons: Non-returnable new parts, no money savings and could fail in a short time.

I purchase a Bosch Aquastar system hoping to save money. So far the system Cost has outweighed any benefits.
The system cost with taxes nearly US Dollars $2000.00
The installation for Pipes (certain size
and stainless still exhaust installation
by profession plumbers (required) $1000.00
Finally the warranty if anything breaks
(besides heat Exchanger is just 2 years
At 2.5 years the control board broke $260.00
Special note if you order the part from
BOSCH- the new part is NON-RETURNABLE
http://www.boschhotwater.com
To installed $150.00
___________
TOTAL $3,410.00

That is a lot of money versus any exaggerated saving
promised by this Bosch system. I will switch back to a Tank.

Pros: Tankless concept looks great on paper
Cons: 1.Water temperature fluctuates,cost too high

Talk about planned obsolescence-We purchased an Aquastar 240fx just 2 years and 4 months ago. The only ting that's under warrenty after that is the heat exchanger.The unit came up with a flashing light and cold water yesterday. I was on hold almost an hour trying to call the manufacturer looking for someone qualified to service it locally. After getting a number locally-their in the door cost is $80 to walk in and $100 an hour to troubleshoot and they didn't have a clue what that so called computer would cost. I finally was able to reach CEC(distributor) tech support and he sent me 2 service bulletins and assured me that I could repair it after cleaning the igniter, the paddle wheel,and the intake screen filter. After doing all of this-the wonderful idiot light kept flashing. Today I am having our utility room replumbed for a regular hot water tank and thumbs down to Home Depot and Bosch parts for ever convincing me that I would save money in the long run.

Pros: Small space required for installation
Cons: Expensive to buy, install and maintain. Very limited service support for the product.

I have owned an Aqua Star 125 for 8 years. Just recently converted back to a high efficiency water tank. During my period of ownership, I experienced high maintenance costs, poor service, and a lack of support from the manufacturer with problems. Limited contractors to service the unit on a regular basis, and at very high cost.

Pros: Nice idea when it works
Cons: bad company {both Bosch and Solarbiz}, many error codes have to reset often

Nice idea bad company:
I bought two of these units {Bosch 240sx} from an online dealer {Solarbiz} (Big mistake: I would suggest buying from the same people who are to install the unit) He didn't want to know me when I had a problem after the sale. He said to call the manufacturer. To make a long story short, dealing with Bosch is like trying to talk to a brick wall and waiting for a response. After explaining to them several times over many phone calls that one unit worked fine and the other was broken, my installer got fed up and said that he will send them back to Bosch ASAP and install two tanks if they don't send out a new one. Well, they finally did send out a dented unit and it works better but I still get error messages several times a week and I haven't bothered calling them again.

Pros: it is tankless
Cons: very high maintenance and expensive to maintain

It is nice when it works, but it breaks down a lot. Most plumbers don't know how to fix it, and even if they are willing to learn they charge you the hourly rate for their education. Service from the manufacturer's representative is quite poor. Parts are very expensive. This unit will not save you any money in the long run. Whatever you save by not heating a traditional water tank you will spend it and more on parts and labor fixing the Bosch. Plus all the discomfort of not having any hot water during the down times. That is really bad in winter when it's too cold to wash without heated water. I really want to like this product for its concept, but I have to say that ultimately it is not worth the money and it is a big hassle to maintain.

Pros: quality,efficiency
Cons: cost

I had a chance to stay at my friends house where i used this water heater i was really amazed about its performance when my friend explained it to me.I had a pleasure when i took bath in it.

Pros: Many games to choose from.
Cons: Web site does not carry through with promise of prize.

Most people enjoy spending time playing games on line. What's better is the hope that you get prizes for wasting your time. Microsoft's club.live website offers such a service. Unfortunately, it seems too good to be true. I must admit that I've played hours of on line games with the hopes of getting an x-box 360 only to find out that when I had enough points, they didn't have anymore. So I went ahead and ordered a Zune. That was on December 13. The website states that it takes 12 weeks to receive a prize. Needless to say, 12 weeks have gone by and I still do not have the prize. Customer service states now that the item is on back order and they are trying to fill orders. So, what do I have to show for my many hours of wasting time? More skills with crosswords and search words, but I still do not have the prize that was offered. So, word to the wise, if you enjoy doing puzzles, go ahead and waste time doing it! After all, the games are free, however, don't get your hopes up for the big prize. It seems very elusive.