Bosch Natural Gas Tankless Water Heater Aquastar 250SX

Bosch Natural Gas Tankless Water Heater Aquastar 250SX

count ratings (37 Epinions reviews)
Share This!
  Ask friends for feedback
  • Thanks for selling it cheap !

    Mar 20, 2012 by
    Rated a Helpful Review
    Cons: Love mine to death !

    Summary: I bought "someone elses nightmare" on for $400. I have two others and LOVE them. This one wheezed and farted on startup and gave inconsistent temps for about a week until I took matters into my own hands. First, LOOK AT THE MANUAL. It ... read more

  • Bosch 250SX

    Sep 27, 2007 by
    Rated a Helpful Review
    Pros: Endless hot water, lower gas bills
    Cons: Installation can get expensive

    Summary: I have read many of the other reviews for this unit on this site and have to say that it looks like every user has had a unique experience with their Bosch Tankless heater. I bought mine off of a friend (no warranty or support from Bosch) and installed ... read more

  • Bosch 250SX Tankless Hot Water Heater

    Jun 11, 2005 by
    Rated a Very Helpful Review
    Pros: Cool heat exchanger. Save money. No more hard water build up to worry about.
    Cons: High gas demand at max output. Stainless steel ducting is expensive.

    Summary: Regarding the review previous to this one, go to and pay $989 instead of $1500 at Home Depot. Takes time to put in yourself but that’s where the fun is. It's not the fault of the heater; plumbing is slow, especially ... read more

  • Bosch Pain on the install, works great now.

    Jul 18, 2006 by
    Rated a Very Helpful Review
    Pros: Endless showers, not risk of 40 gallon water tank leaking in house.
    Cons: temp. adj.; installation costs, problems with unit.

    Summary: I talked my wife into a tank less water heater, told her everyone was going that way. Get that big bulky 40 gallon tank out of the house(ours was installed inside). The thought of that much water in the house was scary enough. She was excited about more ... read more

  • When do we start saving money and get endless hot water? Several recommend Rinnai.

    Jan 13, 2010 by
    Rated a Very Helpful Review
    Pros: Takes up less space, aren't heating water for storage, and you may get a rebate
    Cons: Costs for installing, limited plumbers, cold water when it errors,  water temperature fluctuates.

    Summary: We purchased a Bosch Aqua Star 250sx tankless water heater when we finished our basement two years ago. We purchased this model as it is suppose to handle multiple appliances at one time. We had several reasons in mind for a tank less water ... read more

  • Bosch 250SX tankless water heater .. DON'T DO IT!

    Feb 14, 2007 by
    Rated a Very Helpful Review
    Pros: WHEN it works,the best shower ever, I'm sold on the "concept" of tankless heaters.
    Cons: poor design.when it acts up, you get NOTHING! it doesn't "sort of" work.

    Summary: to start off, I was sold on this by my brother in Houston (this will play a big factor in a minute) who had one installed and worked trouble-free for 6mos. or more, he loved it. I was amazed at the compact size for a "whole-house" heater and thought ... read more

  • bosch 250sx ng

    Mar 3, 2006 by
    Rated a Very Helpful Review
    Pros: It can heat a lot of hot water at once.
    Cons: Not good if you just want to supply a single low-flow usage

    Summary: I bought one locally for $998...and spent at least that much on installation. First usage the heater made a noise so loud I was concerned the neighbors would call the fire department (it sounded a little like a fire alarm). Next day I called customer ... read more

  • Piece of Junk

    Nov 19, 2011 by
    Rated a Helpful Review
    Pros: Just a little bigger than a bread box.
    Cons: Everything else.  Worthless POS.  Customer service, mostly non-exixtent, otherwise rude.

    Summary: Purchased Bosch 250SX 4 years ago to put in attic to free up space in laundry room for remodel.  I paid about $1000 for the unit and then another $500 in expensive stainless steel vent piping and rain cap.  Unit worked well at first until first ... read more

  • Left on the side of the road... for dead by Bosch Service

    Jan 2, 2011 by
    Rated a Very Helpful Review
    Pros: Worked well for 3 years... 
    Cons: Expensive to runsucks a lot of gasPray it doesn't fail... you're screwed

    Summary: Bosch Tankless Hot Water Heater 250SXI would like to title this as "Left on the side of the road... for dead by Bosch Service"3 years into a 12 year warranty, with a catastrophic failure of the heat exchanger, I'm standing in a pool of water ... read more

  • Bosch Aquastar 250 SX

    Oct 18, 2010 by
    Rated a Helpful Review
    Pros: Fairly easy to install. Saves space.
    Cons: Service expensive. Unreliable.

    Summary: This tankless water heater was purchased when I added on to my home and replaced the old laundry room with a new one as part of the project. I bought the Bosch disregarding some marginal reviews of the product I found online, and installed it myself, ... read more

  • very costly and not reliable and over priced

    Jul 13, 2010 by
    Rated a Helpful Review
    Pros: space saving and endless hot water
    Cons: over priced, unreliably equipment, no service parts locally.

    Summary: I bought the Aquastar 250SX in 2005 I have had to remove it twice and put my 40 gallon electric water back in while waiting on parts. The first time was about a year ago when the overheat cutoff fuse went out. The water heater has never worked right ... read more

  • Save your money.

    Oct 20, 2008 by
    Rated a Very Helpful Review
    Pros: Small installation footprint up on wall.

    Should save some money in natural gas bills.

    -Very expensive to purchase
    -Water waster
    -Poor customer support.

    Summary: I bought and received the Bosch from Amazon and didn't get what I bargained for. Prerequisite projects included: 1- installing a new oversized gas line ($350) 2- z-flex thimbles and wall venting for the Bosch exhaust gases($500) 3- ... read more

  • Bosch 250 SX is not for everyone!

    Aug 1, 2008 by
    Rated a Very Helpful Review
    Pros: Small size
    Cons: Doesn't work with shower filters. Tech support is understaffed. Expensive to install.

    Summary: This water heater has been a huge disappointment to me. From the very first, it has had problems with maintaining the temperature. I simply cannot get it to stay at the nice, warm temperature that I want. Every time I shower, the water changes from ... read more

  • kragan

    Jan 30, 2008 by
    Rated a Very Helpful Review
    Pros: All the hot water you could ask for.
    Cons: Watch out if you live where the temperatures are colder than 32 degrees!!

    Summary: Thought this was going to be great. We spent over $1000 on this unit, really liked the idea of conservation and was willing to pay extra, but sometimes "GREEN" is only the color of your $$ flying out of your wallet. You do have to wait a considerable ... read more

  • Bosch Aquastar 250SX Tankless water Fitness Program

    Dec 4, 2007 by
    Rated a Helpful Review
    Pros: You get in great shape with daily runs to the heater's reset Button.
    Cons: The kids don't like running to the basement to reset the heater at bath time.

    Summary: We saw the Bosch 125 SX tankless water heater at a Home depot display in 2003. Since we wanted to gain some real estate for a Basement bathroom we liked the idea of a tankless water heater. The benefits of continuous hot water and energy savings verses ... read more

  • Don't Buy Bosch

    Nov 8, 2007 by
    Rated a Helpful Review
    Pros: When it works and after a lengthy wait it delivers endless hot water.
    Cons: Too long to heat, which wastes water. Not compatible with low-flow clothes washers.

    Summary: I purchased a Bosch 635 ES Pro-Tankless water heater for my home and used a certified Bosch installer to put it in. It has been nothing but trouble. First, it takes > 2 minutes to deliver hot water and my bathroom is less than 20 ft of pipe run from ... read more

  • Bosch 250SX - Not for tract homes

    Sep 4, 2007 by
    Rated a Helpful Review
    Pros: It looks good and takes up less space than a regular water heater.
    Cons: Time to get hot water is too long. Temperature variations are much too large.

    Summary: We purchased this unit because we wanted to more environmentally friendly. We knew that the cost would be more to buy and install ($2100) over simply replacing our old water heater ($700), but felt that it would be worth it in the long run. We expected ... read more

  • Bosch 250SX - Too many shortcoming

    Feb 7, 2006 by
    Rated a Very Helpful Review
    Pros: Multiple consecutive showers without "running out" of hot water.
    Cons: Expensive to switch from tank water heater, poor performance at lower water flows, slow response.

    Summary: Things to keep in mind before switching to a tankless water heater: 1) there may be added costs to replumbing your water lines or your gas lines - since this unit hangs on a wall and your old tank was in the middle of the floor, you are going to have ... read more

  • A questionable replacement for a hot water tank.

    Jan 6, 2006 by
    Rated a Very Helpful Review
    Pros: Endless supply of constant hot water
    Cons: Reliability, Noise, Expense!!

    Summary: I purchased this unit to replace a 50 gallon gas water heater that was on its last legs. The material that I read about this water heater made me thing that this was the right thing to do. After all, how can you argue with unlimited hot water and fuel ... read more

  • Not up to specs

    Aug 23, 2005 by
    Rated a Very Helpful Review
    Pros: Small, space efficient.
    Cons: Irregular hot water output, doesn't work as described in manual, hard to reduce whistling noise

    Summary: Just installed an Aquastar 250SX. We live in the Boston area where extra space is a luxury, the Aquastar made a lot of sense since it would save space occupied by regular water heaters and help reduce the costs of water heating. Hired a local plumber ... read more

  • Never be the first on your block to try this thing!

    Aug 12, 2005 by
    Not yet rated.
    Pros: Looks cool.
    Cons: Doesn't work.

    Summary: I wanted one of these sooo bad. When my hot water heater rusted out, I rushed out and bought the Aquastar with the required SS pressurized venting system, installed a 3/4" gas line under my house, cut a hole in my 80 year-old redwood clapboard siding ... read more

  • Bosch Tankless Water Heater

    Apr 26, 2005 by
    Rated a Very Helpful Review
    Pros: Looks great and well built.
    Cons: Tankless heater did not serve our needs very well.

    Summary: I used to have two 40 gallon hot water tanks that I could run in parallel or series, and normally ran them in series with the first one as a warming tank. One of them rusted out November 2004 and needed to be replaced. A friend told me about ... read more

  • Express Customer Reviews

  • Decent unit and would buy it again

    Sep 22, 2006 by
    Rated Show
    Pros: Endless hot water at a minimal cost
    Cons: lag times and educating others that it doesn't work the same as other water heaters.

    Summary: I like this unit quite a bit. Yes, it involved a bit of new learning curve to install it but once it was in (for the last 7 months) has worked perfectly. It works sufficiently even though we were forced to hook it up to a 1/2" natural gas line rather ... read more


    Jun 30, 2005 by
    Rated Show
    Pros: Always have hot water. Saves $$$ on the long hall.
    Cons: Sticker Shock. One max water temp available at a time. Remotes only store one temperature.

    Summary: Installed in my home in Florida with ground water of 58F temp. After some re-education the family and I love it. We each have our setting and you know when you step in to the shower or bath that the water is the temp. you want. Also bought two remotes ... read more

  • Wonderful product until . . . .

    Jun 21, 2005 by
    Rated Show
    Pros: The unit performed flawlessly and exactly as advertised (endless hot water, no fluctuation, etc)
    Cons: Won't activate with low flow rate.

    Summary: We installed the 250SX 5 months ago. Worked flawlessly. Good water flow, endless hot water on demand. No problems with simultaneous dish washer / faucets / shower demands. Over the weekend it shut-down, gave an error code. Was unable to reset & ... read more

  • Not worth it !!!!

    Dec 23, 2009 by
    Rated Show
    Pros: Space
    Cons: Bosch made heating water complicated and expensive.

    Summary: I'm going to make a long story short. Heating Water Should Never Be This Complicated and Expensive To Do !!!!!!. W ith the money I spent on this unit I could have bought a top of the line Hot Water ... read more

  • Bosch Aquastar SUCKS...

    Dec 4, 2008 by
    Rated Show
    Pros: Saves natural gas energy... Endless hot water...
    Cons: HUGE water waster, costly to install, poor starting performance, no hot water at low flow

    Summary: I am VERY dissapointed with my purchase. I had to have a larger gas meter installed. Had a service guy out after a poorly designed part went bad after a few months. The part was under warranty but the labor was not to the tune of $225. The heater doesn't ... read more

  • 250SX - Should be better

    Jul 4, 2007 by
    Rated Show
    Pros: Saves $$$ over a tank. Mine is quiet. It saves space if inside.
    Cons: Plumber charges to install a 3/4" gas line.

    Summary: My experience is similar to kopperheds. I exhaust vented the 250SX straight up through the roof with all the stainless steel components. But blowing rain will get into the piping and drop straight down filling up the gas valve ruining it. If you ... read more

  • Go with Rinnai

    Mar 21, 2011 by
    Rated Show
    Pros: Keeps us busy with repair calls and selling units that work.
    Cons: Gives the industry a bad name.

    Summary: Professional service tech with 30 years in service loves this product. All of the failures to this unit have made us a lot of money in service calls.Customer service is poor with outrageous on hold times and attitudes to match.Go with ... read more

  • bosch aquastar GWH-635-ES

    Sep 5, 2010 by
    Rated Show
    Pros: Big moneymaker for Bosch
    Cons: everything! completely worthless product!

    Summary: This unit and the company are terrible. I was able to take exactly 2 showers before the unit stopped working. After many phone calls and much money spent on service calls they convinced me to purchase a new internal gas valve for $250. and it still ... read more

  • Bosch gwh-635-es-n

    Jul 23, 2009 by
    Rated Show
    Pros: none
    Cons: Everything about it. Don't buy it!!

    Summary: Terrible from the start I purchased this in 2003 and it errors out all the time and it did from day one. They do not stand by their product. Also after spending 1,500 for the unit it would of took 22 years to pay to get the so called savings they speak ... read more

  • 4 years with Bosch unit--DON'T GET ONE

    Oct 20, 2008 by
    Rated Show
    Pros: Endless HOT water.
    Cons: Either it is too hot or not working at all.

    Summary: I've lived with my tankless Bosch Hot Water unit for 3 years. It stinks. I live in Phoenix, AZ amp; my gas bill doubled the first month I had it. I installed it in a hot month--my old 30gal tank heater (which was installed outside) didn't burn very ... read more

  • I agree, it's horrible along with Bosch support

    Jan 8, 2008 by
    Rated Show
    Pros: space efficient
    Cons: wastes water, much temperature fluctuation, unreliable product, and non-responsive technical support.

    Summary: We had this unit for 10 months, and we're throwing in the towel. It never worked right, we spent endless hours holding for Bosch tech support, nothing got resolved. It is a very touchy unit that goes out frequently. As of now, Bosch will not refund our ... read more

  • It might pay for itself in 50 years

    Aug 5, 2007 by
    Rated Show
    Pros: Could run 3 showers at a time for 7 people after the beach
    Cons: Expensive and tempermental. Horrible, horrible service department, did I mention Bosch service is the worst?

    Summary: Bought into the hype and spent $1200 for the unit, $250 for the installation, $900 for stainless steel vent pipe, 4 service calls in 5 months at about $150 a piece, half of which is the plumber to be on hold with bosch service for 45-60 min. Great when ... read more

  • 250SX

    Jun 4, 2007 by
    Rated Show
    Pros: none
    Cons: sporadic hot/cold showers

    Summary: I purchased the 250SX approximately 1 year ago and have discovered some of the same problems of previous reports. Loud vibration sound when starting. Shower running cold during operation , loud shrill sound while operating. Runs hot then cold then will ... read more

  • Disappointed and Angry

    Mar 7, 2007 by
    Rated Show
    Pros: Energy efficient?
    Cons: Not recommended for well water - bad investment.

    Summary: We purchased our AquaStar Water Heater 250SX appx. 3 years ago and have had nothing but problems with it since day one. We were never told that if you're on well water this unit is useless. The first problem was that the filter in the unit became ... read more

  • A Lemon of a product

    Aug 17, 2006 by
    Rated Show
    Pros: When it works it's great.
    Cons: This particular model is a lemon.

    Summary: We were so excited to get our new small hot water heater installed and running! Until... not more than a month later started having error code after error code come up, loud noises coming from the machine and the only technician in the area for this ... read more

  • Don't buy the hype

    Mar 30, 2006 by
    Rated Show
    Pros: When it works it is great.
    Cons: Be prepared for many hours of problems.

    Summary: I recently purchased a 250sx tankless hot water heater. It promised hot water. I purchased it for the savings, environmentally friendly, and all the other hype. I have had nothing but problems. I have almost always been blamed for it being installed ... read more

Showing 1-38 of 38 reviews