Can an on-demand hot water heater solve my problem?

13 years ago

Our master bathroom is at the end of the house, far from the hot water heater. It takes over a minute, about 80 seconds (more in winter,) to get water warm enough for hand-washing when one tap is open. (If I turn on all the taps and showers, it comes faster.)

Re-plumbing is absolutely NOT an option, for various reasons. So, we can't install a return loop. Also, this is the only part of the house where this is a problem. The other bath, and kitchen, are fine since they are near the boiler.

I'm wondering if there is a way to install a small, inexpensive on-demand electric heater in-line on the hot water feed, which could heat the first minute or so of water until the regular domestic hot water arrives.

That sounds like it would work in theory, no? Can you think of a reason why it won't work?

I'm thinking something like this:

http://www.needplumbingsupplies.com/Ariston-Mini-Tank-Electric-Water-Heaters.asp?id=8030&NpsRfrSrc=Froogle&NpsRfrMfg=12

Here is a link that might be useful: inexpensive on-demand heater

Comments (21)

chris8796
13 years ago
Maybe,

At 1500 watts you would need a dedicated 20 amp circuit to power it. So it may create another problem.
asolo
13 years ago
If you're just washing hands, this little unit will solve your problem. Short-duration of demand is what it's made for. However, if you're taking a shower -- higher flow-rate and longer duration -- that 80 seconds of cold water in the pipe will still come through the exhausted unit and out of the shower-head at some point and surprise you.
Related Discussions
on demand hot water - how long does it take to get hot water?
Q
Comments (3)
The time it takes for the hot water to get to your faucets or shower is related to the distance the water has to travel from the hot water source to the sink and the diameter of the hot water building supply pipe (typically 3/4 inch) as well as the feeder pipe to the sink (typically 1/2 inch). A 3/4 inch pipe holds about 8 ounces of water for every 3 feet of pipe. So if your tank (or tankless) unit is 90 feet away from a faucet, you would have to push out about 1.8 gallons of cold water (plus whatever water is in the feeder pipe, a 6 foot section of 1/2 inch pipe holds about 8 ounces of water) before the hot flows. A typical sink faucet will run at 1.5 gallons per minute maximum flow rate - so you are looking at over 1 minute to get hot water in this scenario. With tankless units, there is also a small delay between the time the unit senses water flowing through it (which triggers it to fire) and the time the unit heats the water up to the set temperature. There are 3 ways you can eliminate the long delay. The first is to put a hot water source (tank or tankless unit) closer to the sinks that are far away from the current source. The second way is to use point of use hot water generators under key sinks that you use. These POU units are very small tanks or tankless units designed to service just once sink. The last method is to install a recirculating loop where you constantly circulate hot water through the hot water building supply. I have a Rinnai tankless system that we installed in the basement directly below the master bathroom. From the time I turn on a shower or sink, hot water is flowing within 10 seconds. That was the good news. The bad news was that the kitchen sink and 3 other sinks that we use often are over 120 feet away from the Rinnai tankless units. Just before we finished the house, we discovered that it was taking several minutes to get hot water at the kitchen sink - and that was unacceptable to us. I wound up installing a recirculting loop. This was not the way I would have preferred to do it, but space and venting in the basement on that side of the house was an issue. You could just live with the delay you have - 1 minute isn't that bad. If you decide to fix the delay, I recommend posting some details on the plumbing forum and seeking advice on how best to correct.
...See More
internal heater (washer) + on-demand water heater (house) = ??
Q
Comments (7)
My setup is really new, but I think the others might be right. I chose NOT to get the machine with heating because my instantaneous water heater has a remote as an option. That would allow me to bump up the water heater temperature temporarily (and thus more safely, to my mind). It costs about the same as the difference in prices between the heat/no heat washers, so I figured I could add that and have that bump-up ability for more than just the washer... *However*, the washer works quite differently from a top loader. (I knew that! That's why I chose a FL. But I didn't know about *this* difference.) When you start a load, it adds a bit of water and tosses a little and adds a little water and repeats until it decides there's enough water. It's not like a TL at all where the water simply runs until it reaches the "right" level. It seems to be based on weight. Mine's an LG (wm2140c, I think), but I'm guessing other new machines are similar.
...See More
tankless hot water heater install problems
Q
Comments (6)
You actually want to run them in parallel. Right now, there's nothing to control where the hot water flow comes from at a given fixture, besides the piping losses (length/size of pipe, fittings). If you have a bigger line to/from the bigger heater, and it's closer to the cold water entrance to the house, hot water will want to come through it preferentially. You can get some brands (I know you can for Noritz) where they communicate between 2 heaters in parallel. But I believe that's really intended for where they're sitting next to each other. With them on the opposite sides of the house, you'll probably need to do what we did. We have a tankless on one end of the house for 2 bathrooms. The older gas tank heater is in the garage on the opposite corner of the house. In the crawlspace, there's a closed valve on the hot water line in between the 2 bathrooms and the rest of the house. Basically, this zones the hot water system. If either heater is out, I can open the valve and feed the whole house. But the 2 heaters don't fight each other under normal circumstances. To get your smaller heater to work, you need a closed valve somewhere. It might be on the extension/connection you mentioned in your OP. But that depends on how much stuff is on the 2 systems. I may be wrong, but I think zl700's check-valve solution would still lead to zero flow through one unit most of the time. That'd be the smaller one, since it sounds like it's running the least now.
...See More
Bosch on demand hot water heater
Q
Comments (7)
Unfortunately you fell prey to a Bosch brand tankless. You didnÂt mention which model, but most tend to be insuperior to Takagi or Rinnai. Many people that enter the on-demand/tankless market buy their Bosch from HD or Lowes, not realizing these units are the lowest quality with minimal features and without knowing never get to experience a quality unit and its pluses. With regards to the manifold system, commonly referred to as a homerun system. Once water comes in, it splits the cold off, then feeds hot water tank at full size which feeds the HW manifold and feeds the fixtures. Because the pipes are much smaller to feed the individual fixtures, hot water is received much faster than a conventional properly sized distribution system. Some will add a recirc off one leg of manifold, reducing time to get hot water at the manifold and thus you only wait for water down the 3/8" or 1/2" line depending on what it is feeding versus a conventional 3/4" or 1" main hot water line. With regards to pressure, it would need to be determined if a booster pump will work if enough water is present in supply line to be drawn and pressurized. If not a storage tank that is pressurized/boosted would be necessary
...See More
User
13 years ago
Here's your answer... http://lainginc.itt.com/pages/autocirc.htm

Had one for years and it works great in EXACTLY your situation.

Search this forum for Laing or Autocirc for previous threads.
davidro1
13 years ago
http://ths.gardenweb.com/forums/load/bath/msg0211025229401.html
I posted to this a week ago.

Here is a link that might be useful: your previous thread in bathrooms forum
joeplumb
13 years ago
"Here's your answer... http://lainginc.itt.com/pages/autocirc.htm";

This is OK but it is wasteful of energy since the long pipes are,on average 90 degrees.

Connecting the hot water line to the cold offers a natural convection solution but is limited and also not energy efficient.

If I had the problem, I would put in a circ pump in series with an NC solenoid stop valve into the connecting line and when needed, actuate the pump/solenoid valve until the water is sufficiently hot and then release the switch. This will get the water hotter faster than a simple opening of the hot water tap and save water.
User
13 years ago
joeplumb,

"This is OK but it is wasteful of energy since the long pipes are,on average 90 degrees".

Is that your opinion or have you actually lived with one?

Cause I have for many years and there is no discernible increase in electrical cost (running the pump) or LP (in my case) heating the water. Not opinion... FACT.

What there was was a DRAMATIC lowering of my water bill and the welcome experience of having hot water immediately (or close to it) available at the kitchen sink at the other end of the house from the water heater instead of having to tun the water down the drain for up to two minutes to just get warm water. An added plus is that all the faucets and appliances in the line between the WH and the far away kitchen have hot water right NOW.

If you search the forum you'll find numerous threads and anecdotal opinions from plumber types challenging these retro fit recirc pumps and in every case it was just opinion and not fact. I have the fact. I live the fact. I have the lower water bills to prove it.

As I've posted before, if a proper return line and recirc pump could be easily and cost effectively added to the home or installed during new construction I would prefer that BUT if your house is on a slab and/or you don't want to rip out sheet rock and deal with that mess in the right circumstance these retro fit recirc pumps can work well and save a lot of wasted water and money.
joeplumb
13 years ago
"Cause I have for many years and there is no discernible increase in electrical cost (running the pump) or LP (in my case) heating the water. Not opinion... FACT."

And just how did you determine the increase in LP?
Also, what is the total cost of installing your device?

As far as my "solution" is concerned, it saves the same amount of water and , since most of the time the pipes in the basement are at room temperature, it is obvious the convective loss is less than in your case.

And no, I have not used it since I don't have the problem, but sometimes one can offer a solution that is based on fundamental principles. That's how they theorized, designed and built the first A-bomb.
User
13 years ago
"And just how did you determine the increase in LP?"

By monitoring my LP costs and my water bill and my electric bill before and after installation of the Laing Aurocirc I determined that LP cost went down because there's less water to heat when I'm not running it down the drain waiting for it to get hot, my electric cost stayed pretty much the same cause the temp controlled pump only pulls 33 watts very intermittently, and my water bill went down enough to pay for the pump before two years was up because I'm not running water down the drain waiting for it to get hot.

"Also, what is the total cost of installing your device?"

One hour to go buy it and 15 minutes to install it... no plumber required.

"As far as my "solution" is concerned, it saves the same amount of water and , since most of the time the pipes in the basement are at room temperature, it is obvious the convective loss is less than in your case"

It will come as a real surprise to you that there are hundreds of millions of homes without basements and/or on slabs and that is why this retrofit is such a slick idea.

"And no, I have not used it since I don't have the problem, but sometimes one can offer a solution that is based on fundamental principles. That's how they theorized, designed and built the first A-bomb"

And you would theorize, design, and build an A-bomb when everyone else would just call Los Alamos and have one sent over.

And sometimes one can offer first hand experience in exactly the situation with exactly the solution that is being offered which is based on fact and not theory.
joeplumb
13 years ago
" 'As far as my "solution" is concerned, it saves the same amount of water and , since most of the time the pipes in the basement are at room temperature, it is obvious the convective loss is less than in your case'

It will come as a real surprise to you that there are hundreds of millions of homes without basements and/or on slabs and that is why this retrofit is such a slick idea. "

I'm shocked. Not so slick; quite obvious.

That's the same type of convection loss-- losing heat to ambient in both cases.

BTW, what is the cost of the device and does the homeowner have to be handy to self install?
User
13 years ago
Far more efficient with far less heat loss than convection because there is a temperature controlled intermittent pump.

Before you criticize you should know something about it... http://lainginc.itt.com/pages/autocirc.htm so you don't just open your mouth to change feet.

There's an installation video, spec sheet, brochure, and instruction manual.
woodbutcher_ca
13 years ago
Hi,
STACEYNIEL ASK HOW TO GET HOT WATER TO HIS BATHROOM. WE FOUND THEY HAVE SYSTEMS TO COVER THE PROBLEM. COST WAS BROUGHT UP BUT NO CLEAR OPINION WAS RAISED. PROBABLY ABOUT THE COST OF A PAY PER VIEW MOVIE ON CABLE.
CAN HE DO IT? WELL I CHECKED OUT HIS BIO HE SPENT 2 YEARS SAILING. HE HAS A FARM IN MAINE. NOW WE ALL KNOW THERE ISN'T MUCH A SAILOR OR FARMER CAN'T DO.
ALSO IN HIS BIO THEY HAD A BOUT WITH CANCER. SO AS THEY STAND THERE WATCHING WATER GO DOWN THE DRAIN IT IS ALSO LIFE GOING AWAY LIKE STANDING IN LINE AT WALMART OR HOME DEPOT OR BIENG PUT ON HOLD.
CARL SANDBURG WROTE "TIME IS THE MOST VALUABLE COIN IN YOUR LIFE. YOU AND YOU ALONE WILL DETERMINE HOW THAT COIN WILL BE SPENT. BE CAREFUL THAT YOU DO NOT LET OTHER PEOPLE SPEND IT FOR YOU."
GOOD LUCK STACEYNIEL.
WOODBUTCHER
chris8796
13 years ago
I've considered the systems that use the cold water line as a return. There are some concerns about mixing hot water in the cold water lines, since it is not recommended to drink water from the hot side. The main concern is legionnaires disease, but others worry about the increased solubility of minerals and other compounds. You'll have to decide if these concerns are important to you.

I also got a chuckle from their marketing, "the average family of 4 saves 43 gallons of water a day"? A 3/4" copper pipe holds 0.025 gallons per linear foot and a 1/2" copper pipe holds 0.0121 gallons per linear foot, 43 gallons would fill 1720 feet of 3/4" or 3553 feet of 1/2" pipe. Now, thats a long from the water heater, even if you had to use water 10 times a day.
User
13 years ago
"I've considered the systems that use the cold water line as a return. There are some concerns about mixing hot water in the cold water lines, since it is not recommended to drink water from the hot side".

The amount of water from the hot side pumped into the cold side is diluted and therefore not the same as drinking hot water.

"The main concern is legionnaires disease, but others worry about the increased solubility of minerals and other compounds".

My wife is an ICP and assured me that the anti-bacterials (chlorine or the like) added in the cold water by our water utility continue to work at a temperature a few degrees over its normal temp and that those same anti-bacterials (chlorine or the like) work just as well in the water heater where the temp is considerably higher than the cold water. I would consider a well water system an entirely different environment since the water is not necessarily safe when pumped from the ground.

I can see where Chris8796 would make that statement never having experienced the device in question so here are facts not unsubstantiated opinions...

The Laing Autocirc and the Watts version retrofit recirc pumps are NSF certified and not prohibited by any code I can find in the US. This link http://lainginc.itt.com/pdf/ACT303Brochure_web.pdf to the Autocirc brochure lists it's certifications.

Living with the Autocirc for 7+ years I never find the temp of the water on the cold side of the sink where the pump is installed to be much above the normal temp of the cold water so any increased solubility is not a consideration and note that no other faucet between the far sink with the device and the WH connects hot and cold.

" also got a chuckle from their marketing, "the average family of 4 saves 43 gallons of water a day"? A 3/4" copper pipe holds 0.025 gallons per linear foot and a 1/2" copper pipe holds 0.0121 gallons per linear foot, 43 gallons would fill 1720 feet of 3/4" or 3553 feet of 1/2" pipe. Now, thats a long from the water heater, even if you had to use water 10 times a day".

With just two people in a 1600 sq ft home we hit a faucet or appliance far more often than ten times a day and factor in the two plus minutes we used to let the hot water run till it was hot and Laing's claims are in the ballpark.

Here are the facts in my first hand experience... no opinion, just fact. My water meter ticks over each 1000 gallons. My average water usage was 4000 gallons per month and every 5th month or so it would drop to 3000 gallons on one months bill then back up to 4000 gallons.

With the Laing Autocirc installed the monthly bills dropped to 3000 gallons for four months and then one month at 4000 gallons. That savings coupled with the savings in KCl for my softener (less water used, less softening needed, less KCl used), less LP used to heat the water, and having hot water at the kitchen sink in seconds was a win-win all the way around.
chris8796
13 years ago
Justalurker,

I can see where Chris8796 would make that statement never having experienced the device in question so here are facts not unsubstantiated opinions...

I think your confused over what are opinions and what are facts. Which of my 3 statements are opinions.
1. Legionnella is associated with hot water systems.
2. Solubility generally increases with temperature.
3. 43 gallons would fill 1720 ft of 3/4" Cu pipe.

I'm glad you happy with your purchase. But, your vehement defense of the product to the slightest criticism only makes you appear as a company shill.

Maybe lead poisoning is clouding your judgement. From the EPA, "Lead is rarely found in source water, but enters tap water through corrosion of plumbing materials. Homes built before 1986 are more likely to have lead pipes, fixtures and solder. However, new homes are also at risk: even legally "lead-free" plumbing may contain up to 8 percent lead. The most common problem is with brass or chrome-plated brass faucets and fixtures which can leach significant amounts of lead into the water, especially hot water."

Here is a link that might be useful: EPA
User
13 years ago
Legionnella is associated with hot water systems.

Yes it is... however as I stated, the device that we are discussing raised the temperature on the cold side of the faucet where it is installed by a few degrees which would not increase the solubility at all or by such an insignificant amount that it can be ignored.

Solubility generally increases with temperature.

Yes it does... chemistry 101. We are NOT discussing the hot water system in a home. We are discussing the cold water system and the device that we are discussing raised the temperature on the cold side of the faucet where it is installed by a few degrees which would not increase the solubility at all or by such an insignificant amount that it can be ignored.

I am not associated with the company in any way.

I offered the OP direct experience over many years with a device that will do exactly what the OP asked about.

The device is modestly priced, easy to install, reliable, does what it is supposed to do, and over 7+ years has had no negative effects whatsoever.

You offer your opinion regarding a device you have no specific experience with you should preface your opinion with that disclaimer.

It is up to the OP and anyone else to look into any product or not and my position is that they should do it based on facts not subjective opinion.

Sometimes you can't teach old dogs new tricks and sometimes you can't teach old dogs any tricks at all.
asolo
13 years ago
Good morning and good news. The site's administrators apparently DO actually exist.

I know this because they just smacked me for what at least one offended party described as an inappropriate post of mine on this thread. I responded to one poster's ALL-CAPS post by requesting he stop that and, in addition, referred to him as a "dingbat." That party was apparently sufficiently offended that they notified the administrators who, then notified me of my infraction.

My callling this poster a "dingbat" was inappropriate. I confess my sin. I acknowledge my guilt. I apologize to any/all who may have been offended and promise to avoid such behavior in the future. I submit to the supervision of the administrators.

Or, maybe I've got it all wrong and they'll decide to kick me off. Their site. Their call.
User
13 years ago
Oh Archie...
woodbutcher_ca
13 years ago
also,
My caps were an accident. I type with two fingers when I noticed the caps were on I was half done and I wasn't about to start over. I figured someone would blow a gasket so I wasn't surprised. As far as dropping a dime on you, I'm a big boy and I don't run to mama.
Good Luck Woodbutcher
asolo
13 years ago
No problem. I know the rules. I broke them. The administrators were correct. I submit...with gratitude, even...assuming they intend to be more vigilant...which they clearly have not been.

However I do wish they'd deal with all the spammers, expansive site-use-compromising ads, and be more responsive generally. I said these things in my response to them along with my mea-culpa and will certainly abide by whatever they decide. Since I'm still here, perhaps I have my answer. I like to think I'm more helpful than harmful overall, but they're in charge and I respect their authority. Actually, I wish they'd BE in charge and exert more authority more frequently.

Between you and me....no worries. Thanks for the comment.
Stacey Collins
Original Author
13 years ago
Well I appreciate those of you who attempted to give me advice on this. I honestly stayed away for most of it after it started going south. Got enough bad stuff and negativity in my real life at the moment, you know? But thanks, and best wishes to you all.
Stacey
jakethewonderdog
13 years ago
Stacey,

Sorry it went off track. To answer your question, yes, that heater will do what you need for hand washing. I would suggest a separate circuit for it.

Can an on-demand hot water heater solve my problem?

Comments (21)

chris8796

asolo

Related Discussions

User

davidro1

joeplumb

User

joeplumb

User

joeplumb

User

woodbutcher_ca

chris8796

User

chris8796

User

asolo

User

woodbutcher_ca

asolo

Stacey Collins
Original Author

jakethewonderdog

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

Can an on-demand hot water heater solve my problem?

Comments (21)

Related Discussions

Stacey CollinsOriginal Author

COMPANY

BUSINESS SERVICES

GET HELP

CONNECT WITH US

Stacey Collins
Original Author