I’m contemplating the instalation of an Aquastar on demand hot water heater in an upcomming project. I’m looking for any input on performance…good or bad?
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Replies
Good, but not everyone believes it yet.
Tom
Aquastars /Bosch work pretty good I've put in 3 so far.Get a powered vent if you can because having an open 6" flue in the winter kind of negates any great energy savings.It can create an incredible draft in the room plus the possibility of back drafts and the pilot blowing out.Keep an eye on the filter dscreen in the inlet line and make sure it stays clean because these heaters are real persnickity about the flow rate
Tt:
Where were they installed in the house? Take up much room? How much $$ are we talking per unit?
Dear Ticktock
I got my first one about 8 yrs ago and it was from a Alternative Energy Dealer such as Real Goods.Since then theyve been bought out or something by Bosch and Ive seen them in the Lowes by us.If I remember it was between 500-600 clams.Mine had an option of adding preheated water (ie.solar).Mine was in laundry room but they are fairly low key devices except for vent stack.There is a learning curve on these buteveryone adapts.
I've been appreciating all the input. I wasn't sure if it would generate much interest. I'm stil not sure if we're saying it's good or not from a performance standpoint. If I'm hoping to run two showers at the same time, am I wasting my time?
Can we make this generic? What are the conditions under which a gas tankless water heater is recommended? And what factors into the choice of appropriate model?
For example, got a couple in a new one-level house built for their retirement. No kids except as occasional visitors. Kitchen and laundry and powder room about 40' away from sleeping wing with master bath and guest bath. How to decide be/t gas water heater in laundry and long pipe to sleeping wing, or tank in laundry and tankless in sleeping wing, or tankless and long pipe, or two tankless?
Cloud,
Tankless water heaters are rated by how many gallons per minute they can heat at a certain "temperature rise". So its performance could be stated like this: 3.5 GPM at 60 degree temperature rise; which means this: if the incoming water is 60 degrees, at 3.5 GPM flow, the maxximum temp. of the output is 120 degrees. Specs are usually given for 50 degree and 70 degree T-rise too.
To size them, take into account the maxximum GPM of HOT (not tempered) water you'll want to have at any one time. Of course, this depends on the fixtures, and the water pressure.
So it takes some MATH to figure out how to size these things, which is probably one of the reasons why some plumbers don't like them.
Regarding your example, I think one tankless will do the job. I don't know which one...my data is a few years old, and there are new ones out now. In the past, I would have recommended a 125,000 BTU unit.
As for what conditions is a Tankless NOT recommended I would say this: When there's no gas available, when you want to fill your bathtub really fast, or when the upfront cost is prohibitive. Or when the larger vents cause a problem in a retrofit, or when the gas line is too small, and replacement cost is prohibitive. I wouldn't install it in a bedroom closet, 'cause the fire is big, loud and it eats a lot of oxygen. I'm sure there are local codes regarding this. Anyone have anything to add?
Tom
Edited 3/30/2002 12:44:14 AM ET by Thomas Moen
Edited 3/30/2002 12:47:05 AM ET by Thomas Moen
I installed one in my own house in 1986, lived there 6 years, and loved it. Always had hot water--used it to fill the hot tub....no waiting after cleaning & refilling.
Drawbacks appear when another hot water tap is open elsewhere in house as this can lower water temp considerably.
GW said:
"Drawbacks appear when another hot water tap is open elsewhere in house as this can lower water temp considerably."
This happens when the wrong size water heater is specified.Tom
These are not nearly as wonderful as a few individuals here would have you believe...
Why's that, WHW? I'm asking honestly.Tom
As stated "intended use" is what makes of breaks the deal. Standard house and the Aquastar will work great. In a house where all hot water demand happens at the same time then divide up the hot water. I have the aqustar in my house and the first comment made was "the hot water never stops" we have 6 people and often shower 4 in a row. ie wife( first out the door), me, son, then daughter then dishwasher when I leave. Yet to find a problem with owning it.
I bought a Takagi TK1 tankless water heater, it is more than I hoped for.
We have five people in my house and I have yet to run into a problem.
I do have a 1" water supply coming into the house though, I'm not sure this makes a big difference but it works well. If you tell them that your a contractor you will get even a bigger discount.
http://www.notanks.com/lowenergysystems/takagi_vs_tank.html is the place that I purchased from, very knowedgable.
So you want me to call Neil at LES and tell him you are lying about the contractor deal? What a low life. I am good friends with the guys there. Think I'll just send them a link.
Easy there... He didn't say he had lied. TOOCH, are you a contractor?
I get your point, Wet, I'm just saying let cooler heads prevail.
I thought of that! But he was advocating this person lie. Unless I missed something. To me that is the same. Or worse.
Good point, I hadn't seen it that way.
Wet, I'm impressed with the majority of your your posts. Tell me about your credentials, experience, etc.?
I will be happy to do that. What is making me laugh is the word you used... "majority". I find it funny. For some reason it just tickled me.
Gotta run now... will do.
I am a contractor, although I am only on my third project.
I guess I was implying something wrong, I didn't even think of getting a better price until the guy on the phone asked me if I was a contractor. I just don't understand why there needs to be two price tiers on internet purchases, if the homeowner who is tackling the job himself wants to give it a go why should he have to pay more than me?
I don't want to start a _itchfest or start slinging words, this is just my opinion and I'll try to keep it to myself from here on out.
No offence. It is a good question. There is actually a very good reason a homeowner should pay more than a contractor (plumbing contractor that is)
When you look at the support issues (via phone or otherwise) the average costs per sale to a homeowner costs more than the average cost per contractor so it is a bottom line issue.
Wet Head,
His words were... "If you tell them that your a contractor you will get even a bigger discount."
I do not read this as encouraging anybody to lie. The way I read it is the same as somebody telling me, "if you tell them you live in a travel trailer, they will give you an even bigger discount".
I do live in a travel trailer. TOOCH was encouraging contractors to let that fact be known.
Just my interpretation.... My name is Luka.
How's that? You get a discount for living in a trailer? Explain, please.
Hey, Wet Head....I repeat...what's not wonderful about tankless water heaters?
Or is it that you think I believe the use of these water heaters will solve all the world's problems?
Tom
Edited 3/30/2002 12:42:14 AM ET by Thomas Moen
As in so many things the energy costs and the dollar costs of production and installation of these products are completely ignored. The ROI is not as wonderful as it is cracked up to be in most cases. (maybe all cases)
Also there have been some deaths directly associated with these heaters. There have been with the regular type too. But I just want ALL the facts to be out on the table.
I never tell anyone they are a bad idea. I just believe that often the whole story is neglected by the proponants of these heaters.
Also there is the issue that most of these heaters will not supply the average American family with enough hot water volumn to support their lifestyle. If the response is that they should change their lifestyle... then I wholeheartedly object to the social engineering issues and it becomes a political issue.
There are more and costlier maintenance issues that are almost always ignored by the proponants of these heaters. As soon as I say that someone will say... "I have had none" Big deal. One or 2 heaters means nothing. I am a professional service plumber. The ratio of repairs is HIGHER than standard heaters. And the lifetime stuff is pure BS. Sure they don't RUST out... but they can catostrophically fail in other areas. And the repairs ARE expensive. Sure they may have no moving parts. Mans absolutely nothing when it comes to repair issues.
I find it interesting that the proponants often feel the need to bash plumbers because the plumbers don't always agree with them. The slobs who bash them because they do not understand them aside... maybe we plumbers aren't as thrilled with them because we know the WHOLE story.
Having said all that... I believe there are more cost effective methods to heat water. If the home has a boiler there is a FAR better method. This kind of heater is a HUGE waste and a STUPID idea in most homes with a boiler in it. But nobody mentions that!
And I think there are some very good tankless heaters out there now. If I ever purchase or build a home without a boiler (not likely) I would probably put a Takagi tankless heater in. They make some of the best ones out there.
I actualy kinda like tankless for some applications. Had one application recently where it would have been perfect... but none of them would reach the 180 degree temp I needed to reach for this app. I was sincerely disappointed I had to go a different route.
So if it seems like I am anti-tankless heater it is because the idealistic, arrogant, and narrow minded view often presented by the proponants just irritate me a lot. My biggest pet peeve in life is being called narrow minded by a narrow minded person! LOL
Am adding this later... one of the biggest performance issues is the dump load issue. VERY few of the proponants of these heaters even know what this important consideration even is. But any competant plumber knows! And very few of these heaters will supply an adequate dump load.
Edited 3/30/2002 9:35:08 AM ET by Wet Head Warrior
Thomas, thanks for the reply (even though I don't use your faucets...........Moen, get it?!?!)
Wet Head, what would you recommend in my case, or do you need more info? They're also planning RFH and no A/C. So is a gas boiler called for? Can it serve RFH and domestic hot water needs? New construction and there's a laundry/utility room with sufficient space for equipment and it's 40' from the bedrooms.
Someone told me yesterday that you set the tankless to produce the water temp you need rather than really hot water tempered to bath temp, for example. True or not true?
What other lifestyle changes might be called for?
Thanks. Jim
Gotta run now... but think on this... 2 smaller size indirect water heaters powered by the boiler used for the RFH... ?????
Awwww...you gotta go just when mom said I can come out and play. :(
I'll research indirect units and come back with questions. Here's gonna be my starting point:
http://www.eren.doe.gov/erec/factsheets/watheath.html
Thanks.
Cloud,
Heheh, Moen Faucets, funny. (being sarcastic :-)
Only affiliated by name. Among those in the construction industry I say "Moen, like the faucet.", or they'll misspell it.
Yes, most all tankless heaters have a thermostat, and the flame can modulate down to a fraction of its potential.Tom
Great! Thanks for finally speaking up, Wet Head.
I've been recommending tankless heaters since the early 90s, when Aquastar first came out with thermostatically controlled units. You would not believe the resistance I encountered from PLUMBERS. MOST of it was because most plumbers didn't know the story, and didn't want to learn. This has changed significantly over the last few years, but its still there.
I personally never intended to imply that YOU were a narrow minded idiot. But, as a plumber, you gotta admit that there are some of those types in your trade. I'm a carpenter by trade myself, and I'm a contractor. We all know there are plenty of idiot non-caring "carpenters" too, as is the case in any field. But I understand your offence, in any case.
Its been my experience, through the installation (not personally, but overseen) of about 25 tankless heaters, that they have been adequate for my clients needs. (Most of my experience came in my other life as a tech at Real Goods.) That said, they certainly have their limits (dump load), but according to my clients, its just not an issue. Maybe this has something to do with our differing markets. I don't always recommend them, but for reasons other than raw performance.
So, WHW, how many defective tankless waterheaters have you fixed? I've had to order one replacement flow sensor, replaced under warranty. Was it you, few months ago, that posted about how some of the styrofoam packing worked its way into the innards, and that the manufacturer's support was terrible?
As for your opinion that the upfront cost and energy costs are "completely ignored" by proponents of these heaters, I say: "I don't think so." What makes you think that?
Try not to be bothered by the social hipness of these water heaters, and we'll get along fine.
Tom
Great! Thanks for finally speaking up, Wet Head.
I've been recommending tankless heaters since the early 90s, when Aquastar first came out with thermostatically controlled units. You would not believe the resistance I encountered from PLUMBERS. MOST of it was because most plumbers didn't know the story, and didn't want to learn. This has changed significantly over the last few years, but its still there.
I personally never intended to imply that YOU were a narrow minded idiot. But, as a plumber, you gotta admit that there are some of those types in your trade. I'm a carpenter by trade myself, and I'm a contractor. We all know there are plenty of idiot non-caring "carpenters" too, as is the case in any field. But I understand your offence, in any case.
I did not take the offence from you but was speaking in general. And nobody gets more frustrated with the slobs in my trade than I do!!
Its been my experience, through the installation (not personally, but overseen) of about 25 tankless heaters, that they have been adequate for my clients needs. (Most of my experience came in my other life as a tech at Real Goods.) That said, they certainly have their limits (dump load), but according to my clients, its just not an issue. Maybe this has something to do with our differing markets. I don't always recommend them, but for reasons other than raw performance.
I think you hit it on the head with the 2 words... "differing markets".
So, WHW, how many defective tankless waterheaters have you fixed? I've had to order one replacement flow sensor, replaced under warranty.
Probably between 25 and 35.
Was it you, few months ago, that posted about how some of the styrofoam packing worked its way into the innards, and that the manufacturer's support was terrible?
Nope... missed that one.
As for your opinion that the upfront cost and energy costs are "completely ignored" by proponents of these heaters, I say: "I don't think so." What makes you think that?
First of all no one mentions the possibility of the entire gas line needing to be replaced in a retrofit application. The venting costs are usually substantial in retrofits also. There are substantially higher energy uses just to build the unit versus a tank type. (Read the data a couple years ago and no longer have access to it)
Try not to be bothered by the social hipness of these water heaters, and we'll get along fine.
You obviously do not know me! LOL I nearly abandoned my plans to build a straw bale house becvause they are TOO MAINSTREAM!
Wet Head,
Since you've serviced a few of these water heaters, can you tell me what, in your experience, goes wrong with them? Is there a weak spot across the board? Or is it one thing after another? Are failures a result of poor design, poor concept, poor installation, or poor workmanship? Are the parts that fail exclusive to tankless water heaters? For example: water flow sensors. I suppose there is a type of differential controller in them too, and a mechanical "flame modulator".
I haven't heard about the increased energy costs to manufacture. I can understand that they are more labor intensive to build, but I don't know about material intensive, although the cost of materials is higher. Let's keep in mind (for others reading this) that, in average use, a tankless water heater is almost twice as efficient as a tanked one. Its average lifespan is easily 3 times that of a tank. This kind of data comes from overseas; from Japan and Europe, where these water heaters have been in use for a long time. That said, the data isn't from Aquastar and Takagi units in use for 30 years. In Japan, for example, Paloma tankless heaters were used for a long time. To my knowledge, these had no thermostat, and no ability to temper the flame. That's a lot simpler design than the ones currently being offered to Americans.
I agree that, for retrofits, there needs to be more emphasis on the possibility of venting and gas line issues. But it'll happen. Just keep telling the truth and why.
There has also been some concern about mineral buildup in the heat exchanger. I have no first hand, second hand or third hand knowledge of this being a problem. But it must have been an issue at some point. Aquastar used to sell a "descaling kit" to remedy this. If your water supply is very hard, I'd recommend a whole house water softener anyway, which should eliminate the risk of buildup.
I said:
Try not to be bothered by the social hipness of these water heaters, and we'll get along fine.
You obviously do not know me! LOL I nearly abandoned my plans to build a straw bale house becvause they are TOO MAINSTREAM!
But that's what I'm sayin'! Who gives a crap if a straw bale house is too mainstream or hip? Was it a good choice? Yes? Did you build it anyway? If so, BRAVO! I love truly independent people. I think the world could use a lot more of them.I Tom
I'll get to the rest later... but had to comment on this... still haven't built anything... and when I do it will be whatever I want to build... the too mainstream comment is a joke I often make... hey, it might even have a tankless in it... depends what makes the most sense at that point...
I just read in a radiant heat website that they emphatically do not recommend using tankless heaters to power a RFH system. One argument was the low efficiency that results from a high return heat temperature. They also claimed that the reason no tankless heaters were built in the U.S. was that they couldn't meet the minimum efficiency standards (74% if I recollect correctly). Any comments from y'all?
"They also claimed that the reason no tankless heaters were built in the U.S. was that they couldn't meet the minimum efficiency standards (74% if I recollect correctly)."
That sound bogus. I don't know about water heaters specifically, but the requirements on most items are based on where they are SOLD and not where they are made.
Otherwise you would be able to get $29.95 water heaters that don't meet any safety or energy specs.
It all comes down to what am I going to do with the hot water!! Is it shower after shower, then tankless is perfect. If its 3 plus showers at the same time then a big water heater with large storage tank ie gym showers in a school. RFH needs 80-90 degree temp water so storage with bypass pipes for tempering is required. If you have a boiler then run a loop to an indirect water tank for storage and use. Tankless is like a big engine, needs a big fuel pipe and a big exhaust but only for short time periods. If space is tight then a tankless is the size of a tall kitchen cabinet. What ever heater you end up with install a water filter, I am always stunned by the 'junk" collected by mine. Softners need to be checked because many of then soften by adding salt to the water and not everyone needs extra salt.
>RFH needs 80-90 degree temp water
Are you sure? I've always been told that the floor temp should go about 10 degrees above the desired room temp and delta-T's should be 20 or more above that. All the engineering I got had temps in the hundred teens. All the recommendations I've ever seen are at least that. If I run 90 water here, I'd never heat. Ever, ever, ever.
Just a rough guide was my intent and to remind everyone to fit their lifestyle with heating water.
This kind of stuff is why I get exasperated with people spouting off when they are totally unqualified to do so. There is heatloss software out there for competent persons to use which will help you design the correct water temp for your design temp, your tubing attatchment method, your flooring material, and your floor covering. Sorry but I get so frustrated being contradicted all the time on plumbing issues by people who are so ignorant on the subject in real life.
Wet Head,
Just to be clear, with whom were you disagreeing? If what I mentioned about temps and delta-t's and such is wrong, I'll go smack around the HVAC contractor and the engineer who's been telling it to me.
Jim
nigel was who I was disagreeing with. My comments were in general.
WHW,
OK. I'll bite. I would have thought that a "dump load" was something handled by the 3" DWV pipe under the floor. But seriously, I don't know what you mean. Can you explain this to a non-plumber like me?
You said, " Softners need to be checked because many of then soften by adding salt to the water and not everyone needs extra salt."
Soften water by adding salt to it? I'll agree that some people may not benefit from extra salt, but not the rest. Do you mean by ion exchange replacing calcium carbonate (i.e hardnesss) ions with sodium ions? Or do you mean that a softener that doesn't rinse completely during regeneration has residual brine in the tank? One of us is confused, may be me. Care to expand?
I thank you for your corrections with reguards to water temp in RHF but I was lead to believe the temp is somewhat dependent on the insulation value of the building and space being heated. I have had three guys trying to sell me water softening systems and two used some kind of salt to "fix" the water. My local water inspector said be very careful because of extra salt. I have a filter installed because of the junk in the water.(its see through and rust bits and other stuff can be seen). Wethead. Are my comments on what and how you use the hot water should guide you in heating methods along the right lines?
I didn't understand your question pal... ask again and I'll try my best to answer.
Wet Head, you said you were disagreeing with me. I wondered about what? As a side question what is a dump load?