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Has anyone out there used a tankless hot water heating system? My wife and I saw an ad recently and she tells me they’re widely used in Europe. What are the comparable costs/installation issues/benefits vs traditional tanks?
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Bob,
I'll skip the cost/benefits details, someone else will know them better than me.
These are typically used in structures that for cost reasons, when only one run of water is feasible and/or it is so far from the hot water source that heat loss in the line is excessive, and a point of use heater is the only way to have hot water on hand.
I have seen a lot of these in some of the older mid to high end homes as a point of use to ensure instant hot water etc... Kitchen/bath.... these are more expensive and are way short of performance compared to water circulation loops and controls and have been phased out in our new homes.
I use a gas one at my cabin/island (Rustic) to have for the kitchen sink, and it is the only hot water supply around. Works great. The down side w/o details is that they are not very efficent, but get the job done.
Europe is big on this way of heating water, without a huge digression they use a lot more of the one pipe plumbing and have 220v as a normal current.
Well it goes on and on from here, codes and more, so talk to a good plumber and get the details. Also go the website of the manufacturer and they should have the details for you.
*Anderson, What do you mean by: "water circulation loops and controls"?Bob, don't be discouraged. Natural Gas or Propane tankless water heaters cannot be beat for efficiency. They are about 80% efficient, which is about twice as good as one with a tank. Tank style water heaters are wasteful because they have to maintain 60 gallons or so of water at 120 degrees 24 hours a day. Even if you are not using hot water, the heater is working. Yes tankless heaters are spendy, but the energy savings is significant, and there is no tank to fail. Its a lifetime investment. Performance? Typical household models will give you about 3 to 3.5 GPM depending on the incoming water temp. These things are good, and there is a reason they are widely used in Europe. Electric versions are not made (very small ones only) because they would demand more current than the average house is wired to supply. It takes a lot of energy (for a small amount of time!) to heat water as its being used. Hope this helps, and you might want to post this over at Breaktime.
*Tankless waterheaters are used extensively in Europe, but you must realize that European houses/apartments are much smaller than ours and often do not have showers. Here, where we are used to multiple bathrooms tankless heaters may not prove ideal. Tankless will, of course, never run out of hot water, but they also have a limited supply. I used a 185,000btu unit so that I could supply 2 showers with low flow shower heads. Anything smaller would not be adequate if both were in use at the same time. This unit required a 6" vent, and that was an issue since this was a retrofit and the existing vent was 3". I ended up relocating the heater and using a powered vent, so saftey features will not allow the heater to light in a blackout. Combustion air supply can be an issue on a large unit where outside air is required. European installations are typically exposed in the kitchen drawing heated combustion air from the building interior. Here, we are used to having the house's infrastructure hidden away.My neighbor has a tankless water heater in use that was installed when his house was new in the 1920's. It is a cast iron unit that looks something like a pot bellied stove, filled with copper coils. He has had the copper repaired once. Life expectancy makes the initial cost factor, probably about $1000 +, less of an issue.
*One more thing. I installed the tankless myself. I have had considerable plumbing experience and am well versed in code and procedures. The damn thing kept going out. I followed all the trouble shooting procedures, called the distributor, worked with them and still no luck. Finally, while I was out of town I had my wife call a plumber whose name I got from the distributor. It turns out that an internal baffle had dislodged during shipping. It took someone thouroughly familiar with the unit to diagnose and fix the problem. I never would have found it myself even with the excelent product support I got.
*Gents,I lived in Europe for 7 years and there were on-demand water heaters everywhere. You have to get good ones, but they worked just fine. I'll think about installing them in my house when the time comes. But I wouldn't expect one to handle the whole place. You might want to consider having, say, one for the bathrooms exclusively, because when they run out of hot water, you get out of the shower, fast.best,dave p.
*Folks, lets remember that tankless water heaters don't really run out of hot water, but if you draw more GPM than they can supply, the water will get colder, and some will spew freezing cold water when seriously overloaded. Many newer tankless water heaters (Aquastar) reduce the water flow when overloaded, so the result is lukewarm water rather than cold. I think its important that we don't make too many ignorant generalizations about this type of water heater, because #1, they are THE most efficient way of heating water and #2, they work when the right unit is chosen. I don't hear the owner of a 20 gallon tank style water heater complain about the poor performance of all tank style water heaters. He knows enough to replace it with a larger tank. The same logic applies to tankless heaters.At the risk of offending plumbers, I'd have to recommend that you don't rely solely on the advice of one when shopping for a tankless water heater. My experience is that many plumbers just don't want to learn anything new or different, especially from a non-plumber. There are ALWAYS exceptions, of course, but be cautious. This observation of mine only applies to the subject of water heaters, so keep that in mind.
*Mike, I'm curious as to why you didn't replace the 3' vent with the 6"? Something in the way? Its too bad it won't work now when the power is out.Its true, they don't work in every situation, but do work in most. If you are concerned about supplying multiple showers plus a kitchen in the morning, perhaps a couple 185,000 BTU units would be appropriate. In this case, the gas line from the main might have to be bigger than normal if the central heat was gas too. Spendy for sure, but a house that has so many hot water needs is big (spendy) anyway. Call me strange (or "underpriveleged"), but I've never personally had to run so many hot water fixtures at once. How long does a shower take? 10 minutes? Americans, geez. But that's another subject.About the baffle that came loose...that's something you know about now. There are similar quirks with everything in building, as I'm sure you know. Since we are generally thoroughly familiar with the way we build things, and the systems we traditionally use, we are able to diagnose and fix and odd quirk, just like the mechanic with your truck. Don't dis it because you were unfamiliar with it, if that's what you were saying.
*I used to live in downtown Seattle. Now I live on the side of a mountain, in one of those aforementioned 'rustic' settings. I am VERY interested in a tankless water heater, but so far have only seen small electric types available. How can I get info on better, preferably propane style ??? It only has to supply enough for a shower or two in the morning, and dishes at night. But it must be up to that at least, or I will be tempted to go find a large tank type.Also, it seems logical to me that I would have only one water feed to the destination. No cold feed, only through this to the sink/shower. This would lend itself to less of a tendency to running over the GPM supply. (I would have a seperate drinking/cold water supply. I already do anyway.)I would also want to have an easily adjustable temp, so I could make the temp hotter for the dishes than for the shower, without having to fumble in the back of the laundry room every time.TIA for sources of info, as well as suggestions and recommendations.
*Thomas,The original "tanked" waterheater was downstairs in a 2 story installation. The 3" vent ran up through the walls to the roof. There was no way to route a 6" vent through there. I could have gone to an oval that would have fit in a stud bay, but I would have had to tear out everything all the way up. The tankless supplies my mother-in-law's attached apartment, so there is no real control over the timing of the two showers. The next time a baffle comes lose I'll know. I'm sure that's how the plumber learned that one, too.
*Luka, type "Aquastar" in a search engine. They make great tankless heaters. They make a 80,000BTU (max input) unit that will probably work fine for you. They also make 125,000 BTU and 170,000 BTU models. They have a thermostat. HERE'S AN IMPORTANT POINT: THE 125,000 BTU UNIT, FOR EXAMPLE, WILL GIVE 3+GPM AT 60 DEGREE TEMPERATURE RISE. SO IF THE INCOMING WATER IS 50 DEGREES, THE OUTGOING TEMP IS 110 DEGREES. AT 90 DEGREE TEMPERATURE RISE IT WILL PROVIDE A LITTLE OVER 2GPM (LAST I CHECKED). THE THERMOSTAT SETTING AND THE INCOMING WATER TEMP. DETERMINE HOW MANY GPM YOU GET AT A CERTAIN TEMP. The 3GPM limit in this case means that the heater will heat 3GPM at 60 deg. temp. rise, but more water can pass through the heater. At 4GPM, the temp. rise will be less. The limits aren't hydraulic, they are thermal. You should install separate cold water feed too for more flow if needed, and to temper the shower temperature while effectively getting more GPM.Real Goods, at http://www.realgoods.com, is one of the best sources for these types of water heaters, as well a source for all kinds of things for folks living on sides of mountains. I was employed as a "tech" there for about 3 years. Good Luck.Tom
*Tom,Thank you muchly. :-)After the realgoods site I started a search and got sidetracked for a couple hours poking around on self-reliant websites. LOL Long story short, with the cost of the instant water heaters, I am now considering making my own wood-fired water heater. I know eventualy I'll pop for a propane powered one anyway, but you might as well play while ya can, no ?Thanks again.
*I've lived in Japan for over 20 years total and there are lots of "instant" or demand-type water heaters in use here. It's mostly due to the reduced space requirements in small houses. I've seen units that vary from over-the-sink jobs about the same size as a microwave oven, to larger stand-alone units that sit outside and provide more flow capacity. As someone else said, while they'll provide hot water till the cows come home, the drawback is that most of them (the smaller ones particularly) don't provide it very fast. You won't get the kind of pressure most people expect from a tank-type heater.They're easy to install and handy for small apartment kitchens, though, even though they don't help the looks of the kitchen much. Another potential drawback is that some flow-limiter faucets will cause so much back-pressure that the heater's sensor will think the faucet has been closed, and respond by switching off the fire. You go from ice to fire with nothing in between.Visit Virtual Fujino, JapanGreen Gables: A Contemplative Companion to Fujino Township
*I have been researching tankless also. There is a website called PLUMBNET where you can get all kinds of info. Just do a search. Another tankless brand is a Japanese product called T-K1. They have a web site too.
*My wife and I decided to install an Aqua-Star 125NG in our home when we remodeled it in 1995. I have been familiar with tankless heaters since the early 70s from travels abroad and thru friends in this country. Everything from funky home-made jobs thru production wood-fired and propane,NG and electric.Ithink they are great if used properly and that is the catch, as many of the messages attest to. First off, they take some getting used to. Our Aqua-Star will heat about 3gpm @ 60degrees increase. That translates to water about 110degrees. Plenty hot for a shower. I do not try and run a laundry though at the same time. Neither do I try and fill the tub. However I can run the dishwasher or if someone turns on the hot tap, I am fine. We work within the limitations of the system, something we Americans seem to be teaching the rest of the world to ignore as well. We stagger our hot water demands. Another tip in use is to set the temp setting on the heater to maximize the hot and minimize the cold demand. Why heat water only to cool it to use it. This took my wife and daughter some time to get used to, but now they appreciate the water heater as much as I do. Another tip, insulate all you hot supply lines from heater to taps. Since there is no constant heat or storage, the pipes do get cold and take time to warm again. There are several other considerations as well besides effeciency. One is space requirement. Our heater is mounted on the wall in the laundry room/pantry. It is straight stack vented through the roof. The wall space it occupies is 16inchs wide x 30inchs tall x 12inchs deep. Compare that to a standard tank heater. Cost was a bit more upfront. WE paid $625 for ours when a gas tank heater of good quality was $350. The gas hook-up and venting were similar for both. But even the best tank heater will give you only 10 years of life on the average especially around here with our water. I am willing to bet the aqua-star gives me at least 25 years and then I only need to replace the coils. Installation was by myself and we have had no problems. I agree with Tom M. about plumbers as a rule. Like alot of us in the trades we want to tackle what we are familiar with and shy from new ideas, especially when money or the loss of it is involved. I am lucky to have a plumbing company who though new to the idea never the less were interested in learning about this heater and have profited by the knowledge. I will end this with a short story. My wife's 3 sisters and mom came for a visit. Everyone wanted baths and showers, including my wife and daughter. I came home from playing soccer soon after the last shower wanting one myself. The dishwasher was running. I took a nice hot long shower. Walk goodsome additional web-sites. Aqua-star is now made by Bosch and they have a closed combustion unit available as well as a pilot-less one http://www.cechot.comAnother make is korean and looks good though I have no experience other than review. It is by the Targa Energy Co. http://www.targaenergy.com
*Sounds like Paloma (a brand). Newer heaters turn on at .5 GPM flow, which is less flow than restrictor faucets use. At least in the U.S., that is.
*I've used the Thermar heater (now extinct) for 10 years now, the only issue that I have with it is that I have had to ADD whole house water filtration to prevent particulates from clogging the diaphram assembly. It also drops temperature when the furnace comes on, other than that it's been great having an endless supply of hot water....
*Just to balance this out........Still working on plans for new house, but 2 baths and kitchen (single story) are located about as far apart as you can get. Will have crawl space. Does anyone know even a rough way of figuring added operational costs if I set up a thermostatted--and maybe timered--heat loop, if I insulate it REALLY well? (Like double layers of foam tubing, or somesuch?)My experience w/ gas water heaters is that they last almost forever. And a high efficiency, sealed combustion tank unit is a WHOLE LOT LESS than 3 tankless would be.
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Has anyone out there used a tankless hot water heating system? My wife and I saw an ad recently and she tells me they're widely used in Europe. What are the comparable costs/installation issues/benefits vs traditional tanks?