You also don't need to have an indirect tank, a tankless water heater, or a tank type water heater if you have a boiler. The boilers that I am familiar with (limited) are in effect tankless water heaters that have a small heated tank located inside the unit.
A couple of thousand for an indirect tank could be considered to be a waste of money.
By the way, I have nothing against a standard tank type water heater. I needed the floor space, so I used a tankless. I now have a direct vent gas fireplace taking up part of the floor space where that old water heater was located. I needed to heat my home theater room that I located in the basement, and the gas fireplace was a nice way to provide heat for that zone. The gas fireplace also keeps me away from problems caused by HVAC contractors!
One other note, I really liked the vent system for the Rinnia. It is an outer 5.5" pvc pipe for combustion air intake with an inner 3" steel exhaust flue. Easy to cut and work with. Cost more than "B" vent but possibly more long lasting and doesn't take combustion air from garage in my case
BTW, My boys and I made the pilgrimage to Mecca and saw the Red Sox play last year at Fenway!
Last edited by gregsauls; 01-19-2009 at 08:15 AM.
What's the payback period for the indirect, 20, 30 or 40 years?
Seems like indirect systems have their own set of problems.
I live in MA, and a tankless works fine in my single family home here even with water coming in at 40 degrees. Just stay within the flow rate of the heater and you will never have the problem of running out of hot water.
If you "need" to run three shower heads at the same time when you shower (AKA large demand), then a tankless is probably not a good idea anywhere.
I am not sure if the electric version of a whole house tankless is a good idea. From what I have read, some utilities prohibit their use due to excessive short term demands on the power grid.
Interesting you bring this up... A couple of the upper end tankless units have a communication cable option so up to three units can be paralleled together so they can "talk" to each other and provide a greater flow rate. We are about to install just such a parallel set up at a Boy Scout camp here to supply 6 showers and ditch the 50 gal electric water heaters in favor of propane. Being on the camp inspection cmty, getting those once a year maintenance descalling done will not be an issue!
What does 2 Rinnai's, the installation materials, the electronics to "talk" to each other plus installation cost with nothing donated or discounted ?
If you were getting a price from me it would be in the 5 grand range.
And the cost of a 50 gallon electric? Around 300 bucks for the takn and maybe another 250 to put it in.
So $550.00 against $ 5,000.00.
And once again the payoff is --- Drumroll please
UNLIMITED HOT WATER
Last edited by gregsauls; 01-19-2009 at 06:29 PM.
It would be interesting to try to follow NHmaster's advice. One little 50 gallon electric heater for six showers in a camp. Funny how you already have multiple electric water heaters and they can't keep up with the demand.
I notice that you have followed some of NHmaster's advice.
"The world is full of stupid people. Try not to be one of the crowd."
So you base you undying love for this crap on the fact that you can get the stuff and labor donated. Great, wonderfull, good for you. What about everybody else. I get it just fine. In fact I get paid to GET IT.
If one 50 gallon heater wouldn't do it you could put in 3 more and still have it cost less especially if your gracious plumbing supply sold them to you at cost also.
I'm done with this thread. It's an illogical total waste of time for anybody that is actually considering purchasing a tankless. 99.9% of folks can't get the equipment at cost and 95.9% of folks don't have the skills or tools to install the thing. Basing cost comparisons on essentially "free" equipment is rediculous. However free or not free the operating cost doesn't change and even at "cost" a 4% savings just breaks even. Good by..... Oh and when you start having problems with the thing(s) you only have to answer to a whole campground full of angry campers not just the wife and childdren.
If you have the right physical layout, this would be the ideal situation for drain heat recovery units (lots of showers, high fuel cost). Preheat the incoming cold water with warm drain water. It is easy to get a 20 degree rise in incoming water temp (45 to 65) and has an actual payback.
2.2 gal/min x 6 showers x 20 degree F x 8.8 lbs/gal = 2323 btu/min
Propane is 91600 btu/gal x 80% water heater efficacy / $3 gal= 24400 btu/$
2323 btu/min / 24400 btu/$ = 9.5 cents/min, (When all 6 showers running)
200 campers/6 showers x 6 min/shower =200 minutes of showering
200 mins x 9.5 c/min = $19.00 a showering cycle.
I would assume $1500 in capital costs w/free labor. Thats about 79 shower cycles for full payback, so it depends on how often the camp is used. You also get the benefit of increased capacity and no maintenance issues.
I have to agree with NH on this issue. I looked at the Navian website and was suitably impressed. I was actually thinking about going that route when my water heater dies, until it came to finding out the price and local distributors. The link to the distributors didn't work and through a bit more Googling I found prices of $1500 and up, plus shipping, of course.
I can purchase THREE tank-type water heaters for the price of that Navian. Sure, I'll lose a bit on efficiency and pay a bit more in natural gas purchases but damn, I still think that I'll come out ahead by the time I die by going with the old tank-type.
And just in case someone wants to know, figuring ROI is what I did for a living for too many years.
DHRU. They become more attractive with high volumes of hot water use, high energy costs and colder cold water temperatures. I would geuss they start to become viable for residential use with households averaging more than 30 minutes of showers a day and avg cold water temps of 55 F (possibly less with high energy costs). Crunching the numbers at my house I save about 1 cent per min of showering x 30 minutes a day (4 people) x 365 days = ~$110 per year. Capital costs were $500 DIY or probably $800-1000 if professionally installed. The DIY numbers are no-brainers with 20+% ROI. Even 10+% ROI is good for some and below the cost of capital. They are obivously not viable for every application, but have good potential in some applications, such as your camp scenario.
Is this device code approved because it presents a very real possiblity of cross contamination should the exchanger be breached.