Tankless Water Heaters - New Thread

[Brentbba]

I'm going to start a new thread as all the tankless water heater threads here on plumbing central MUD are old and gray...like 2006-2010!

Anyone with more recent use and info? Recommendations?

We're about to start a remodel and part of that is putting down new tile where the current 50 gal tank water heater is. It'll need to be disconnected regardless. It's a good 8 years old and with the rock hard water here in SoCal is reaching it's end of life anyway so we figured why not look tankless. We've gone energy efficient wherever we can as we upgrade the house.

I've read quite a bit and the Rheem RTGH-95 for a 'large home' system seems to get the best reviews and write-up's across several sites.

Neighbor has an older tankles unit and ended up putting in a water softener as the hard water here ate up the copper in his unit in about 5 years. I've read about putting in inline water filters to help that'll need changing annually, making sure the system is plumbed properly to allow for a scaling flush, etc., all of which sound very necessary with our hard water.

 

[1911]

We have a Rinnai RUCS65i in my shop / apartment, and love it. It's only 130,000 BTU and 6.5 gal/min, but it's plenty for the two of us. We're going to put two larger ones in the house we're building. I paid extra for a wall-mounted thermostat (so you don't have to get inside the heater to change the temperature), but we found that leaving it at 120 is more than good enough for everything we'd use or need. It's been faultless for a year and a half. Love never running out of hot water, and not having to make space for a big tank that has to stay heated all the time. Ours runs on propane, and we have not had to refill our 500 gal tank in two years so far (propane tank runs Mrs. 1911's big range/ovens also).

We are on well water which is quite hard. We have a Nuvo whole-house chelating filter that helps a lot, but Rinnai still requires you to back flush the heat exchanger with vinegar once a year to keep the warranty in force. Easy to do yourself with a 5-gal bucket and a small submersible pump. I have only done that once so far, but will say that it did make a difference in shower volume afterwards.

I'm totally sold on the tankless heaters, and would never buy a conventional tank heater again. I'm happy enough with our Rinnai to buy more from them for the house.

 

[Redgrrr]

My neighbor who just retired from a life long career as a master plumber just helped me put in a tank water heater in my place. His advice knowing I won’t be keeping this house for more than 5 years turned me away from a tankless heater for a few reasons. One being the savings in energy won’t pay for the added cost of the unit while I own the house. And two old simple technology.

If I was keeping the place for 20 more years he said to get a tankless.

 

[Redgrrr]

I have $450 into parts for a Rheem. Space was not an issue either as I have a large utility room.

It would have cost me $1400 in parts for the tankless heater with the same specs for my 4 bedroom house with 4 people and laundry needs. So the savings in energy didn’t make sense to make the change. At our gas rate it would have taken 10 years to pay me back.

On top of that I just listen considering he’s helped me fix many problems my 35 year old house has needed for upkeep this last ten years. We also just did my furnace and didn’t go high efficiency because of the cheaper parts cost and venting changes needed.

 

[Brentbba]

Good comments. We'll probably be in the house a long while as we just cant afford to move in SoCal! Been in this house 21 years so our mortgage is low by today's standards here.

We would need to add electricity to utility room which would not be hard. Looks like 3/4 gas line already. Would need to upgrade vent stack to roof tho.

One respected guy has ready said to let our current rank run it's useful life, then replace it. That would bu guy us a little time and not rush into this decision.

 

[GeoRoss]

I have mixed feeling about tankless water heaters.

Number one, if space is an issue, tankless is the way to go. If space is not an issue then I'm not really sure it is worth it.

Number two, they have to be used. My current house has three water heaters. Two in the main and one in the guest house. I put in tankless ten years ago. The unit that fed the kitchen and a bathroom that was rarely used and the guest house failed within 5 years. The one serving the bathrooms used daily (showers) is still trucking with minimum maintenance. I really do think that regular use is really important they don't like sitting.

Number three, go with a pilot light style. I have had both and the pilot light and electronic ignition styles. The pilot light style is much more robust. I've had to replace the electronic ignition on units not used daily several times, once under warranty. This may just be a Bosch issue. There are styles that do not require external electricity like the pilot light style units. You may or may not need to do some gas line work. They are gas hogs.


Number four, our incoming water temp varies seasonally by 20˚ or more so I have to adjust the temp through the year but not a problem. You may have similar issues.


Number five, go with Rinnai or Paloma. Both of those come with piping that is for both exhaust and intake. The Bosch I have just use regular B pipe and I do have trouble in the winter with ignition. Make up air is not the problem. Avoid Bosch at all costs. Also make sure you have the exhaust properly routed with a minimum of bends. The piping will be larger than what you have in place and will require enlarging what you already have.