Tankless water heaters

[Toolman]

Looking at purchasing a propane fired tankless water heater. Anyone have experience with these? They seem to be more efficient.

[submarinesailor]

I have looked into them and plan on putting one in one of these days.  Based on life cycle costing, they are normally much lower in cost to run.  Also, the one I like best is the Rinnai:  http://www.rinnai.us/Products/water_heaters.aspx.

They may cost more, but seen to be much more reliable.

Spell Check - did I just see a spell check working on this reply??
 
Bruce

[zopi]

I just got done re-plumbing the entire house with PEX and installing  a rinnai water heater...love it!

I have three girls and a wife, good bloody luck getting some hot water...with the tankless it is endless..

and yes, it is quite a bit more efficient.

they say they work nicely for a booster to a solar unit too...but you have to use a tempering valve
as the unit won't take more than a certain temp of input water.

[Gordon]

Tankless with propane is the only way to go!!! The rinnai is a very good unit, I installed a few of these the past few years. The key to these is a very short vent as it's very expensive. Another thing is hard water can reduce the efficiency of the coil with scale build up.

Gordon

[StorminN]

Get a unit without a pilot light... you'd be surprised how much gas a pilot light uses. Rinnai must make one and I know Bosch makes an AquaStar that doesn't even have to be plugged in, the water pressure creates the spark needed to light the flame (through a little water wheel or something?)

-Norm.

[logwalker]

I went with Takagi TK Juniors for my infloor heating. It is a backup for the wood boiler. I heard many negatives about the Bosch. Surprising as they are usually pretty good stuff. The takagis have a 10 year warranty as a heating boiler. Joe

[Toolman]

Thanks for the reponses. I was looking at the Bosch AquaStar. As far as scale buildup on the coils, I do have hard water(iron,sulfur, not much lime) I was going to add an additional whole house filter prior to the heater. Somebody told me that when they change their whole house filter, they fill filter housing with lime-away, then run their tap for a minute to allow solution to enter into pipes,then wait for fifteen minutes for lime-away to work scale loose. They then turn tap on all faucets to get rid of any solution in pipes. Anybody ever try this. I have reservations regarding this. Concern of ingesting this stuff.

Appreciate any input

[Mooseherder]

How much do these cost ballpark figure?
Couldn't find any pricing.  I hate that.

[Gordon]

I've installed one Bosch and havent heard another thing about it so it must be working fine. The reason for the Bosch over the Rinnai was cost, a few hundred dollar savings. Anyone can buy the Bosch, but you must be cerified to buy the Rinnai from the supply house.

Both models use a ramped flame. The faster the water flow thru the heater the more btu is put out for --- the larger the flame.

Something else that must be considered is the existing gas line size. Make sure your gas line is large enough or figure in the cost of running a new larger gas line to the new heater. Your gas line can't be smaller than the inlet of the heater.

Gordon

[zopi]

How much do these cost ballpark figure?
Couldn't find any pricing.  I hate that.

ours was a couple grand installed

[Don P]

Good to see you Gordon  

We had a Takagi installed on the job for the radiant system. It has worked fine so far. We did have some issues with the stack, the planned exit developed too much length so we had to back up and go through the foundation wall. I have heard of cold air getting in through the exhaust and freezing some units. I believe this one had a sensor that would call for flame if that begins to happen (not positive, better check that) There was a kit that is a section of pipe with a damper that fits just above the unit in the stack. If a wind comes in it shuts that damper. We ordered that as well. If the exhaust is impeded by a shut damper it will shut down. Although we have it facing west and have alot of exposure to the prevailing wind it has not shut down to my knowledge. Now that I know a little more I'll watch for that placement better in the future.

I think I'd rather use vinegar in a potable supply, but I'd check with the manufacturer first.

[Left Coast Chris]

Did anyone find an operating cost comparison between propane and electric versions?  With propane so high in cost would'nt electric be cheaper to operate at some point?      The electric cars are starting to look pretty good.

[zopi]

I'm in a rural Coop..kinda expensive for electric, plus the propane tank is like 15 feet from where I wanted it.

[Toolman]

Here in Pennsylvania, deregulation kicks in 2009.  Electric companies are already telling folks to look forward to 30-70% increase next year. Thats why I'm trying to get away from electric. I'm already looking into solar panels for the house, but that's a topic that needs a thread of it's own.


Thanks for all the input guys, appreciate it.

[zopi]

Here in Pennsylvania, deregulation kicks in 2009.  Electric companies are already telling folks to look forward to 30-70% increase next year. Thats why I'm trying to get away from electric. I'm already looking into solar panels for the house, but that's a topic that needs a thread of it's own.

By the time i get back from japan in a few years, i am hoping the nano panels will be a bit more
mainstream, and known reliable...my goal is to be mostly water and electric independent..oh..I'm already water independent..just want one more deep well for insurance and irrigation.

[Handy Andy]

  When we built my daughters house, we put in a rheem tankless water heater.  Price was about half of the rinnai (spelling?)  and the only negative was we had to mount it on the end of the house against the basement wall.  The thing only came with enough flue to go through a 4" wall, and had to get a piece to go through the 8", even though we went through the rim joist above the wall. It works well, but on the end of the house it is a long way to the bathroom on the other end.  We used pex pipe, and the manifold system, so takes a long time to get hot water, and even if you have it warmed up one place, still is a long time to get hot water to another connection.  Need a water heater on both ends of the house. 

[StorminN]

Andy,

I toured a house with a setup where the guy put in a little circulator pump and some creative tee plumbing... he had a timer switch (like a bathroom fan crank switch) that he would turn on, wait 10-15 seconds, and then turn the hot water faucet on... he had hot water right at the tap by then. It's inconvenient to use the timer, but it eliminates a second heater, the cold-water-turning-to-hot, and still uses less energy than a not-on-demand heater.

-Norm.

[JSNH]

You mentioned hard water. My neighbor has had a few Tankless hot water heaters. I beleive he is on #3 now over 25 years. He has hard water and the coils rot out. By the time the coils go the parts are not avaliable so he buys a new one. If you have hard water look at the life cost of the unit. You may be better off spending money on a solar preheat with a simple to replace gas or electric heater as the primary. Granted the tankless are modern, cool and efficient but one must weigh the savings and additional cost.

[StorminN]

You may be better off spending money on a solar preheat with a simple to replace gas or electric heater as the primary. Granted the tankless are modern, cool and efficient but one must weigh the savings and additional cost.

JSNH is right, solar preheat is good bang for your buck, if you do it right. I couple of vacuum tube collectors like the Apricus or Thermomax, and a wand heat exchanger in your hot water tank will work.

If you went that route, though... I'd stick with an electric tank, at least you can super insulate them. The gas-fired hot water tanks sometimes have a pilot light (wasted gas) and they ALL have a central flue with heat baffles... this is efficient for getting the heat from the burned gas into your water, but as soon as the flame shuts off, the flue and baffles are just as efficient at getting the heat back out of your water and up the chimney...

-Norm.

[Don P]

Some thoughts since this thread started,
Our tankless on the job passed inspection and should have failed, I'm installing a outside combustion air duct now... ooops 

The instant hot recirc system at Lowes the other day was priced around $200

Water heater timers on conventional water heaters probably have a better lifetime cost than the tankless.