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Water heaters
I have been looking into getting an on-demand hot water heater; but in talking with some local plumbers they are leary of them. Main reason is costs, a good on-demand cost up to $1700 compared to a $700 regular system. Another issue is that they need special ducting for their chimney. A couple of plumber I talked to said the life expectancy of an on-demand is about 1/3 to 1/2 of a normal water heater.
Where our cabin is located we would have to completly drain the system to winterize, and the on-demands seem to have a certain amount of water that cannot be drained.
Anyone have any thoughts on this.
Where our cabin is located we would have to completly drain the system to winterize, and the on-demands seem to have a certain amount of water that cannot be drained.
Anyone have any thoughts on this.
Views: 21
Replies to This Discussion
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Permalink Reply by Randy Esposito on -
I use an electric on demand in my house to back up my solar hot water system. They are made by Siesco. http://www.seisco.com/
A large whole house unit costs about $800 or you can go with smaller units for each bathroom, kitchen.
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Permalink Reply by James Goddard on -
Virtually everyone here in Japan uses on demand. Surprising that they are so expensive. The guys up in remote AK use them a lot as well...
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Permalink Reply by Gravitas Design on
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We have specified them a few times. http://www.rinnai.us/tankless-water-heaters/
They have a 12 year warranty on heat exchanger and they "last 20 years", claiming 2x as long as a tank, so I guess it depends on who you ask.
Also, you can install inside, requiring the vent, or on the inside of an exterior wall (which direct vents, no vertical pipe) or install them on the outside of an exterior wall which requires no venting.
Don't forget: 30% off of the unit and installation through 12/31/10 with the federal tax credit.
Derek
Derek Hurd
Principal
Gravitas, Inc.
1524 W. Hays
Boise, ID 83702
www.gravitas.us
twitter.com/gravitasboise
208.367.1184
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Permalink Reply by Bob Bell on -
Our log home has an on-demand system that serves our needs perfectly. However, we're not in snow country and have no experience with draining the system. We're on propane gas for fuel. The input information you've heard is a little off base. The special ducting is a double-wall exhaust/intake. That way the unit, which is about the size of a carryon suitcase, can be installed just about anywhere. The unit itself is cool to the touch. Life expectancy is probably 3x a regular hot water heater. Mine is guaranteed on paper for 25 years. What I've had a problem with is adjusting to the wait for the hot water to travel from the unit to the faucet. All my life you turn on the faucet and hot water comes out. To solve the issue I've installed a circulation pump on a timer that runs a couple of hours in the morning and again in the evening. If you want to take a shower at 3pm, you have to run the water for about a minute in my faraway master bath. The water heats right away but must now travel 100' or so. My advantage to on-demand is about 40% less use of propane, my original purpose. My water is from a well and I suspect I use a little bit more. Unit cost is higher but the stimulus plan knocks off approx 30%.
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Permalink Reply by Terry Tadysak on -
I paid less than $500.00 for mine. I installed the Eemax Tankless water heater. Call 1-800-543-6163 or 203-267-7890. Mine is 3 elements. Order one with the stainless steel elements as they will last much longer. Its not much bigger than a city phone book. You need a plumber and an electrician. Try to mount it near your electrical panel. If you have PEX piping in your cabin you are in great shape. PEX can freeze w/o leaking. I would ask the manufacturer what to do when turning off all heat. I asume the unit can freeze w/o problems but I would ask.
They have dealers throughout the U.S. I have had mine 5 years and it works great. Two showers going at the same time - no problem.
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Permalink Reply by Mat on -
I have three questions on this topic:
1. Is one tankless heater always enough? Or do you sometimes need to cascade them?
The temperature of the water coming out of the tankless heater is a function of the input water temperature, heater capacity, and the flow rate I believe.
Is well water always the same temperature (assuming a well of a few hundred feet in depth)? Or does it vary based on season? What temperature should I assume for using in calculations, assuming the pump is at a depth of 400'?
The flow rate can be controlled by not running the dishwasher and clothes washing machine at the same time that you are showering, so this aspect of the equation should not be a problem.
2. Minerals / stuff in the well water -- since water isn't sitting in a tank there should be no sediment collecting, correct? And that should help tankless water heater lifetime, correct?
3. Is the venting for a tankless heater similar to that off a direct-vent fireplace (i.e. can vent *almost* horizontally through a nearby external wall)?
I want to go the "tankless" route too since it allows you instant hot water when you arrive at the cabin versus having to turn up the water heater tank and wait an hour.
thanks,
Mat
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Permalink Reply by Bob Bell on
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Mat, first of all I'm no expert on the subject. I did my research and so far have been pleased with my installation. Your questions...
1. One heater "may" be enough. In not, you may install several. However one high(er) capacity should do the trick. High capacity includes adequate gas flow (propane regulator), adequate input water pressure (though my Rinnai unit only needs #20). Since the units are so quiet and want to install a secondary unit nearer to the source of use- why not near a bathroom, laundry room or kitchen? My installation was a direct replacement for my single 50 gal water heater, in the garage. It's rated for 2 showers, a sink and dish washer. The unit pump is variable speed and takes care of increased loads.
Ground temperature? There is a difference in ground water temperature. It seems reasonable that cold water won't flow or pressurize as easily as warm water. However, my well fills up a pressure bubble and I'm sure the water temp is just about the same when it enters my tankless water heater. #2, the digital temp display on the unit guarantees its output. Mine is set for 130 degrees, therefore I expect 130 regardless of all other variables.
2. Sediment/stuff in the water? My unit has extra valves and hose input for flushing, if it becomes necessary. Straight water or vinegar, no big deal.
3. The venting is exactly the same as you describe.
Hope this helps, Bob
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Permalink Reply by Joe on -
Matt,
First of all remember that water is incompressable so temperature doesn't affect flow rate unless it is frozen or boiling. The time it takes to heat it could vary depending on starting temperature. The one nice thing about well water is the temperature should be fairly consistant year round.
Water can look clear but still carry contaminents, have iron, lead, etc. and still smell. Sitting around doesn't improve this.
The problem with well water is that many times it smells of sulphur and can contain a lot of iron depending on where you live. I would certainly have it tested for chemicals and hardness. If it contains things like iron it will clog up your pipes over the years and stain your outside walls, driveways, etc. It can also be very "hard" which your wife will hate for washing her hair and dishes.
Depending on what testing shows you may want to put in a sediment filter, a carbon filter and a water softener.
I ran into all of these things on a house I bought in Michigan. We had to replumb the house up to where the filter was as the pipes were almost completely clogged. The well water stained the house foundation and walkways.
Joe, sarasota
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Permalink Reply by Bob Bell on
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Agree with Joe. Sears will give you a testing kit in the hopes you will purchase future equip from them.
I should have mentioned I have a Home Depot Whole House Filter when it leaves the pressure bubble. There was a small earthquake about 100 miles from me about 5 years ago. We never felt it but it disturbed the aquifer my well pulls water from. We sucked sand so badly it clogged my lawn sprinkler valves and sand residue rested in the toilet after flushing. That's when I installed the WH Filter. Cartridges cost around $10 each. I was changing those filters once a week for about a month, then once a month for awhile. Now I check the filter every 90 days but consistently change a clean-looking filter cartridge about once a year now. Without looking I think it's 5 micron; it sez drinking water quality.
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Permalink Reply by Richard Clauson on -
Been a plumber for 45 years. Your guy is giving good advice although on demand heaters are nice. Cost has been coming down so shop around. If you go with electric, duct work will be eliminated although on demand uses power like an arc welder. You will need a 30 to 50 amp 220 volt circuit. They do wear out faster then a storage heater but how fast is questionable. Have your plumber install drain valves so the heater and piping can be drained. Use a professional that has done this type of work. ENJOY
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