Experience with Tank-less water Heaters

[Tractor Seabee]

We are about half way to closing on our new house. I want to convert to a whole house tank-less WH and looking for voices of experience. will be natural gas direct vent condensing type. I have boiled it down to 3 brands; Rheem, Bosch, and Rennai in their top of line. I am more interested in life and problems than cost.

Who out their has experience with these brands? How long has it been in? Problems? Would you recommend it to your best friend? Any help will be appreciated. Thanks in advance.

Ron

 

[madpuma13]

We are about half way to closing on our new house. I want to convert to a whole house tank-less WH and looking for voices of experience. will be natural gas direct vent condensing type. I have boiled it down to 3 brands; Rheem, Bosch, and Rennai in their top of line. I am more interested in life and problems than cost.

Who out their has experience with these brands? How long has it been in? Problems? Would you recommend it to your best friend? Any help will be appreciated. Thanks in advance.

Ron

I had a house with a rennai, loved it. After doing my own research, I will be installing another in our new home.

Word of caution. Tankless water heaters does not mean maintenance free. It is highly recommended to flush the heater once a year. A very simple procedure especially if you plan ahead for it.

 

[Kentuckyfarmer]

I have had a rennai for going on 2 years. Not one problem. A good friend has a rennai for over ten years and not one problem and never has flushed his as of yet and he recommended it to me several years ago. It's like he said to me you can fill up a Olympic swimming pool and not run out of hot water. My gas bill went down from over sixty dollars a month in the summer to under 20. Heating water is the only gas used in the house during the summer. I didn't get the cheapest one and it has a better water flow, I think the cheapest one was like 7.5 gallons per min and the one I got is like 9 gpm. It was preset for max temp of 125 but you can flip a dip switch or two and run it up to 145 I believe it is. I have it set to 130. Should have gotten one years ago.

 

[dstig1]

I have a Takagi. 2 yrs old and the heat exchanger started leaking. I went for warranty repair and they sent me a new one with instructions on how to replace (NOT easy!!) and told me to send them photos of the old one when it was out. Did that and they told me they were giving me the exchanger as a goodwill gesture, but that they would not warranty the heater for this again, as it was caused by hard water. I was a bit shocked that they could tell this from the photos, but apparently they have seen this a million times. They didn't need it back so i cut it open to see. There were some thin deposits on the inside of the tubes which is apparently all it takes to ruin these things. What happens is the minerals deposit on the walls and build up. This insulates the water from the flame and causes the exchanger to overheat locally, which eventually leads to a leak. Here's the rub. We moved in Aug without a water softener. It quickly became obvious that we needed one and finally got it in place in Nov. Water was around 20 grains hardness or so, IIRC. That was all it took to ruin this thing. Just 3 months. Now if I had acid flushed it somewhere in there to remove the minerals, that may have solved it, but my idiot plumbers did not put a flush valve kit on it. I added that when I had it down for the exchanger swap.

With all that said, I love it. But it is clear that you need to be super careful about water hardness going into it. Also when you install these, make sure you put a flush valve kit on them so you can easily maintain the unit. Like this thing: 44443WPR - Webstone 44443WPR - 3/4" IPS Isolator E-X-P E2 Tankless Water Heater Service Valve Kit (Lead Free)

 

[SpringHollow]

I have had a Takagi for a while now and it has worked very well. My water is moderately hard. I did install something similar to this before the heater:

Amazon.com: Aqua-Pure AP43SS Hot Water System Protector: Industrial & Scientific

 

[dmccarty]

Search TBN for more discussions about tank less water heaters. There have been a few and seems like some discussions were quite long.

We thought about putting in a tank less water heater but we decided against it for a couple of reasons.

• It would have to be electric and the temperature rise was iffy.
• It was far cheaper to have an 80 gallon water heater.
• The 80 gallon water heater is a nice source of water if we are out of power.

Years after we moved into our house, we were talking to our plumber. He said he now refuses to install a tank less water heater since he had so many problems with them. The big problem was water hardness. So if you do put in a tank less water heater, I would make sure the water supply was in spec for the heater. Hopefully the tank less water heaters specify water quality.

Later,
Dan

 

[Sigarms]

I have had a rennai for going on 2 years. Not one problem. A good friend has a rennai for over ten years and not one problem and never has flushed his as of yet and he recommended it to me several years ago. It's like he said to me you can fill up a Olympic swimming pool and not run out of hot water.

You need to ensure you know what your recovery rate is and at what water temp.

It IS possible to actually run out of hot water with a tankless heater if it isn't sized properly.

If you're on well water, due to scale build up, you'll want to clean the heat exchanger at least once a year.

If I lived back up north, I'd probably go boiler with storage tank. Best of both worlds although a lot more money.

 

[justinramani]

+1 for Rinnai - we had a LP exterior mount installed when our house was built. Our one unit is capable of supplying enough water for our house and guest house. We love it - consider exterior mount if your climate allows for it. No need to worry about venting.

 

[Oldoak]

Well, I have an odd brand tank-less water heater, Quietside. Going on almost 5 years now. Never been flushed and never had a problem. Operates on Propane. Residential natural gas is not available in my rural area. Also have a Peerless high efficiency, direct vent boiler for hot water baseboard heat. Very happy with both. Cost of operating varies with the price of Propane.

What we really love about both, we can still have hot water and house heat when using our generator during storms and power outages.
Couldn't do that in our old house with an electric hot water tank and electric baseboard heaters. It would have required a much larger generator at a prohibited cost for us.

 

[SpringHollow]

There is a huge difference between NG/LPG and electric whole house tankless units. It is very hard to find a reliable electric tankless unit unless things have changed in the last few years. I remember researching them and even one of the most highly rated ones had serious issues. One apartment manager bought 24 for use in his apartments. Within 1 year, 32 had been replaced. Yep, some had been done more than once. I can not remember if it had a 3 or 5 year warranty but he was expecting to replace them many times. On the plus side, he had it down to a science from doing it so many times and he could replace them relatively quickly. The smaller single faucet electric ones seem to have fewer issues.

Ken