We're using a Rinnai tankless exterior mount unit for our master bath which has 9 fixtures (if you count each body spray individually). I'm not sure which exact model we're using yet...that's my husband's department! We're also using an 85 gallon Marathon hot water heater to service the rest of the house. We have been impressed by this product, which of course, means that no plumbers in our area are familiar with it!
I haven't done enough research on the first question to be able to answer it in any detail. I think that this came up on a previous thread though...

Here is a link that might be useful: Marathon water heaters

trudymom - we are also in central Texas and just went round and round with this. We were planning on getting a tankless but decided against it when I talked to a few different people regarding the water. Well water so far in central Texas as not treated tankless heaters well from what I am hearing. I talked to a plumber just three days ago and he stated that they are having to flush them out with a special chemical, darn he told me the name but I do not remember, and that the lime in the well water in some parts of the hill country are just causing lots of build up in the tanks.

After talking to our plumber, posting about the tankless here and getting feedback and finding a few people around who had them, we decided it was not worth the extra money to get one. We have already been told our regular water heater will probably last 5 years before we will need a new one because of the hard water from the well. The last think I want to do is buy the tankless for a thousand or so and then have to buy another one 4-5 years later, maybe sooner.

I would suggest really looking into it and talking to the plumber and getting his thoughts on it.

Good luck either way :-)

trudymom- as long as you have a softner that is rated for your conditions you should be fine. You should also have a whole house filter to protect the softner and the rest of the plumbing. One other thing is the make sure that your water is not acidic(sp?) as this can cause as much damage, or more, than hard water.

Kelntex- if you water is that hard, you are going to have more problems than just the water heater. Hard water damages everthing it touchs over time. Dishwashers, washing machines, clothes,toilets,showers, it etches dishes and glassware ,etc...

If you have not considered a water softner, I urge you to do so. BTW, to replace a tanked hot water heater can cost $800-$1200. Before a tanked water heater is ruined, its capacity will be diminished by 1/3 to 1/2 due to the same scale and lime build up.

I will add that we also will be on well water.

Anyone else?

Thank you!!

We're on well water and have two SETS tankless units. At first we had a problem with the hot water never getting above luke-warm in the main unit. It turned out to be a minor part. We emailed SETS and they asked us to do some testing which GC and DH did. Once that was done SETS overnighted the part to us and the problem was solved.
I can see where not only calcium could build up over the years but also sediment might be a problem in the beginning as well. So far sediment has been our biggest problem. Our build took 3 years and I guess there was a lot of junk that made it into those pipes over that time frame. DH has removed the filters on every faucet and cleaned them for about 5 days in a row now and we're still getting small rocks etc out of them. I believe he's flushed the tankless as well but it's a good question to ask tonight.

rarl - we do plan on getting a softener no doubt about that! I have dealt with the hard water here in central Texas for some time now. I can't tell you how many bottle of Lime Away I went through in our first house years ago! LOL!

If you don't live with municipal running water stay clear of the tankless water heaters. I live in rural area have water softening unit, water neutralizer & blending tank of 100 gallons but I didn't have 300 gallon holding tank that the rinnai system could draw pre-treated water from so it could supply my 87 gallon jacuzzi or a Shower with seperate wall jets. These Tankless water systems draw water & Nat gas/Propane at an incredible rate in order to utilize quick heat. The plumber told me a designed system in a rural area with water softener/neutralizer, blending tank & holding tank was 10K. installed.
Consequently I dropped that Idea & went with a Solar-electric system & (2) 80 gallon tanks one to pre heat the water the other to hold the water & using my existing softener system cost 6k. Plus I do not have to be worried as much at the cost of OIL/Utility bills I think you can presume that OIL (Propane) prices will be high for the rest of our lifetimes. That is the fuel the tankless heater was to use (BTW the cost of the Propane tank was another 5K to have it buried, 2500K if I didn't have it buried on top of the 6K price I just quoted you!

I guess you're saying that because of your well size your plumber said it would take $10,000 to install a tankless when it's really to increase the well size. We have a large well and a 500 gallon secondary tank (a forest-fire dept. requirement). Our tankless unit itself ran less than $1000.
And we're in California!... LOL!