# Tankless NG Water Heater Recommendation?



## Ralph III (Oct 7, 2011)

Hello Everyone,
Does anyone have a natural gas tankless (whole house) water heater recommendations or input? I'd like to disconnect our gas hot water heater and install a tankless unit instead. I"d then eventually use the hot water heater as a pre-heater.

Our home is 3k square ft with 2 1/2 baths. We use quite a bit of hot water in a given day between two adults and two children. It probably fluctuates between 30 - 50 ga though. The main daily consumption is filling a garden tub at least once and running a load of clothes in the washing machine in addition to maybe one short shower. The dishwasher typically gets run every other day and several other short showers, so that would account for the high consumption days. 

1. We typically are not running multiple items at the same time so the demand is never really outrageous at any given moment. 

2. Does the vent system have to be changed out from a standard gas water heater to a tankless gas water heater? The unit will be located in our garage, btw.

3. How much savings could I expect?

I appreciate your input.

God Bless,
Ralph


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## ChuckTin (Nov 17, 2014)

I'm betting you'll need one tankless unit per hot tap. One day of running low or out of hot water and you'll regret the change over.


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## georgemcq (Feb 19, 2018)

Take a look at the Takagi tankless heaters. They have sizing charts on their website but you will probably need a 199,000btu unit.
Sometimes you can reuse existing vent lines but if you go with a condensing (more efficient) tankless then you will switch over to either 3" or 4" PVC.


Make sure you have a 3/4" gas line serving the heater as in most cases 1/2" is too small.


Good luck. You will probably get more responses if you post in the "Plumbing Section" rather than appliances.


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## Ralph III (Oct 7, 2011)

ChuckTin said:


> I'm betting you'll need one tankless unit per hot tap. One day of running low or out of hot water and you'll regret the change over.



I only need it to be able to fill a bathtub or otherwise run a shower. The bath or shower will not be occurring at the same time. Nor will the bath or shower occur when other appliances are running (dishwasher, washing machine). So how do you figure it will run out of hot water?


Ralph


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## user_12345a (Nov 23, 2014)

What problem are you trying to solve?

Tankless units are expensive to buy and service. They have proprietary parts and are very complex. They don't have a reserve - think about power outages and breakdowns.

They save fuel but not normally enough to justify the high costs.


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## DanS26 (Oct 25, 2012)

Think long and hard before you go tankless.

Google "hot water sandwich" before you commit.

The amount of water you and your family send down the drain because you are afraid of the cold water sandwich will more than offset the savings that your plumbing salesman guaranteed you will be saving.

It is amazing the plumbing industry is still selling these things.

You have been forewarned.......


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## roughneck (Nov 28, 2014)

What is the quality of your water? 
A lot of iron? Hardness?


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## iamrfixit (Jan 30, 2011)

I installed a Takagi 10 gallon per minute natural gas unit about 3 years ago. It easily handles several points of use at the same time, although the temp can fluctuate a little when you drastically change flow through the unit. It takes a few seconds for the temp to readjust and match the new flow rate. If I turn on both showers, and all four sinks, it can easily supply all of them simultaneously. All the hot taps in my house together can reach about 8 gallon per minute. This unit will maintain 120F even with incoming water temps likely dipping into the 40s in winter. 

It does take longer to get hot water, probably about 15-20 seconds at the nearest sink and 30 seconds in the kitchen as it's the furthest away. If someone uses a bunch of hot water while you're in the shower the temp changes a little, it's mildly annoying but not a huge temp swing. Cold water sandwich has never really been a big issue, you just get used to running the shower a minute before you jump in. Tankless isn't a great option if you have hard water, it will require much more maintenance.

The tankless is really nice for filling large tubs or those times when several showers have to be taken in a row. I can set the temp at 105 and fill my 500 gallon hot tub and it's ready to go immediately rather than the next day. My gas bill dropped about $5-7/month after install. It's the only gas appliance running for half the year so it's easy to see. Didn't notice significant increase in water usage although I imagine we do waste a little more water waiting for it to get hot.

I went with tankless because of previous experience. I had helped a friend install two of them in his car wash a few years earlier. He'd been buying 100 gallon high capacity commercial units about every 3 years at about $5000 a pop. We installed the two tankless units for about half of that and they've been in use since around 2011 with pretty much no issue. When my power vent unit failed it was $750 not including install. I have no flue pipe through the roof so a standard tank type is not an option. This is a condensing tankless unit, so it uses two 3" PVC pipes directly out through the wall, one for intake and one for exhaust.


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## Ralph III (Oct 7, 2011)

Hello Everyone,
Thanks for all the input and let me clarify a few things.

1. I am not fixing any issues associated with our 50ga gas water heater. I simply want to make our house a little more efficient in order to lower our utility bills.


I've done construction and remodeling most of my life so I'm assuming I can do the install myself? After taking the 50ga hot water heater off line my plans were to then use it as a pre-heater for the tankless at some point. So instead of it having to warm up 59 degree water it would only have to warm up 80 degree water or so.... 

2. I do not see Hot Water Sandwich being an issue at all. We always check the tub temperature and adjust as needed while it is filling. In addition, it takes about 25 seconds for hot water to reach the shower so nobody ever gets into the shower prior to that. 

3. I'd have to check the water quality but iron isn't an issue whereas hard water could be a concern. We definetly do not have soft water.

We just need something that could supply enough flow for one shower. Really if it takes 15 or 20 min to fill the tub that is no big deal but it must support a shower. Consequently, I was assuming a tankless 4.0 gpm or 5.0 gpm would be sufficient. 

Our demand is spread out over the day or most of the evening. We never have a high demand all at once.

God Bless,
Ralph


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## iamrfixit (Jan 30, 2011)

Ralph III said:


> Hello Everyone,
> Thanks for all the input and let me clarify a few things.
> 
> 1. I am not fixing any issues associated with our 50ga gas water heater. I simply want to make our house a little more efficient in order to lower our utility bills.
> ...





I have my old 30 gallon electric water heater set up in line ahead of the tankless and my ground source heat pump desuperheater is used to heat the water in it. I don't often run it through the winter because I do lose a little heating capacity when the desuperheater is operating. I do run it all summer when the AC is on and it does preheat the water although not really enough to supply hot water on it's own except during stretches of extremely hot weather. 

If I didn't have geothermal to make free hot water, I wouldn't even bother. The tankless works more evenly without the preheated water and it doesn't need any help. I do have the old electric water heater connected to power. If the tankless were to go out I could just flip the breaker on and have hot water in an hour or so. 

The link I included is for the 10 gallon model, you can also get 8 or even 6gallon, but the savings was not enough to sell me less capacity. Looks like less than $50 savings for the 8 gallon and about $175 savings for the 6 gallon. When I bought mine they were even closer in price.

To do this to strictly reduce your utilities, I think tankless would have a pretty long payback. The space savings is pretty significant, having it hung on the wall freed up a lot of space in a congested area. The endless hot water is the biggest benefit. I actually needed a new water heater so it only cost me about $300 more to go tankless.

It can be DIY, I installed mine. I use electric for heat but the house already had a 1" main line. The only other gas appliance on the place is a small furnace for the garage. If you were to have several gas consuming appliances you may need to upgrade the main gas line to larger size and in extreme cases maybe even the meter. Another option may be to have the utility company switch you to higher pressure gas service and regulate pressure at each appliance. 

I carefully read the manual and installed the vent and intake according to the directions. Installing this is really no more complex than installing a tank style heater. I had to make changes to my gas line, separating a couple joints and installing a larger Tee for the water heater. I have years of experience fitting pipe at work, so this little gas line project was no issue for me. After completion I pressure tested the line and checked each connection with soapy water. Also you'll need a good manometer to verify correct gas pressures during the full range of heater operation.


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## chandler48 (Jun 5, 2017)

> So how do you figure it will run out of hot water?


You'll run out of hot water when your gas supply is depleted. Otherwise it will keep heating until you are through. We don't have the demand you have, but are very satisfied with our Rinnai unit. Venting is 4" PVC, as opposed to the early version of tankless which required quite expensive triple wall pipe.


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## Ralph III (Oct 7, 2011)

Thanks!


Let me ask one other question.


Would it be cost effective to install a 120v or 240v tankless at the shower alone? There is a large cavity behind the shower everyone uses that could be made accessible from a closet. The tankless unit wouldn't be easily accessible though (not sure about code) but it could be accessible once a year of ever so often to check on it. Running single pole 120v would be easy as I have a line available already. I'd have to run new wire for 240v over 40ft so that would cost a little more.


Ralph


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## raylo32 (Nov 25, 2006)

That sounds like a good idea to me and I have thought about doing it for my master bathroom that is the most distant from my regular nat gas tank WH. But in my case I don't have a lot of extra room for one or an easy way to plumb it... and no way to get 240V service up there through 3 floors of finished space and walls... so I just live with what I've got.... which means I need to run the hot tap on the tub for 20 seconds or so to get hot water to my bathroom for a shower... or run the shower for like 45-60 seconds. And forget about just running a hot sink tap and getting hot water today. <sigh>

I also looked hard into tankless when I replaced my tank WH awhile ago but the retrofit costs were just way too high, having to run intake and exhaust pipes, upgrading the gas lines... and maybe even the gas service and meter. Made no sense at all. It would be much easier and make more sense in new construction as long as the water hardness and maintenance issues are understood.



Ralph III said:


> Thanks!
> 
> 
> Let me ask one other question.
> ...


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## iamrfixit (Jan 30, 2011)

Ralph III said:


> Thanks!
> 
> Let me ask one other question.
> 
> ...



Even a small electric tankless takes a lot of power. The smallest I've seen would still require a 30 amp 120v circuit. Friend has one of these in his garage, it can barely warm the water to wash your hands and it takes a good 30 seconds to even do that. Good for less than half gallon per minute flow, as long as the incoming water doesn't get too cold. In winter the water from the faucet can barely be considered warm. 

A unit large enough to handle a single shower would probably require around 50 amp at 240v which would likely require #6 cable at about $2 a foot. A whole house electric tankless can easily take 3-4 times that. In most houses it would also require a major upgrade to the electric service to handle it.


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## chandler48 (Jun 5, 2017)

> The tankless unit wouldn't be easily accessible


How would you flush it? Don't forget proper maintenance.


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## Ralph III (Oct 7, 2011)

chandler48 said:


> How would you flush it? Don't forget proper maintenance.


The unit could be mounted on a wall within the bathroom. I would then create an access door within the master closet to the attic cavity (located behind shower) that would allow me to service the unit from the backside. So there should be no issue there.

It's just not readily accessible because I'd have to move clothes and such in order to access it.

Take care,
Ralph


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## pwcopy (Aug 27, 2017)

In 2000, I built my dream house and installed a Bosch Aquastar 125B tankless. Other than changing the ignitor batteries (2 D-cells) every couple of years, it was NEVER touched. Never serviced, never flushed, never nothing. It just quit a couple of months ago. The upfront cost ($900) installed was more, but... Did I ever run out of hot water? No. Did I ever pay a service bill? No. Did I save $$ over the approximately 2.5 tank heaters I would have used over the same time period. Yes. Did I save on NG? Yes. On the recommendation of a plumber I trust without question, I had him put in a Navien 180S. This time the cost was $1950 total. It can fill the whirlpool in the master bath and run a shower full blast at the same time. (I haven't tried running 3 fixtures at once. I question the experience of those telling you that you'll need "one tankless per tap," or "they are expensive to maintain and repair." That hasn't been my or my neighbor's experience (they put in a Rinnai 10 years ago). Just endless hot water and no service or repair bills. I'm a tankless fan for life.


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## user_12345a (Nov 23, 2014)

When hot water needs are low (2 to 3 people showering), even if a tankless saves 40% it doesn't make economic sense to go tankless.

There may be other good reasons to get this type of water heater.

Some units may run trouble free for many years, others may require very expensive repairs. 

A tankless unit is basically a modulating wall mount boiler -> the gas valve and inducer are variable capacity, it must constantly monitor leaving water temperature and adjust fuel input to deliver the correct temperature water. The electronics needed to make this happen are proprietary.

I haven't looked into repair part costs but wouldn't be surprised if the circuit boards on some are $500 to $1000 at cost and need to be ordered.

A conventional tank water heater on the other hand can be fixed with mostly inexpensive parts commonly stocked on a service van.


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## House Designer (Oct 4, 2019)

Ralph III said:


> Hello Everyone,
> Thanks for all the input and let me clarify a few things.
> 
> 1. I am not fixing any issues associated with our 50ga gas water heater. I simply want to make our house a little more efficient in order to lower our utility bills.
> ...


You sound like a frustrated engineer! (Tongue in cheek)
You want to take something that is working fine, and then replace it for no good reason. You will double or triple the complexity, cost, and maintenance of your system in the hopes of saving a tiny amount of money that will require a 30-year payback. All the while introducing new issues that you could not foresee.

Reminds me of a friend with a very suitable economy car. He replaced it with a Chevy Volt because it would make his daily round trip commute more efficient. Shortly after, Ohio introduced a $300 annual tax on plug-in hybrids, to recover lost road taxes from people with electrics who don't pay their fair share of gasoline tax.) Now my friend spends more on this annual tax each year than he saves in gas.


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## pwcopy (Aug 27, 2017)

An additional two cents. I have traveled extensively in Europe and Asia. In those parts of the world, you will almost never see a tank water heater. Tankless water heaters are the standard in home, commercial and industrial applications going back to the 1940s. (Of course, what would most of the rest of the world know about anything, right? 'Murica!)


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## House Designer (Oct 4, 2019)

Good point, pwcopy.
The average house in Europe and Asia is so small (compared to the US) that they are more likely to seek tiny sized appliances, including water heaters. Tankless water heaters DO save space.
https://www.elledecor.com/life-culture/fun-at-home/news/a7654/house-sizes-around-the-world/


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## Ralph III (Oct 7, 2011)

House Designer said:


> You sound like a frustrated engineer! (Tongue in cheek)
> You want to take something that is working fine, and then replace it for no good reason. You will double or triple the complexity, cost, and maintenance of your system in the hopes of saving a tiny amount of money that will require a 30-year payback. All the while introducing new issues that you could not foresee.
> 
> Reminds me of a friend with a very suitable economy car. He replaced it with a Chevy Volt because it would make his daily round trip commute more efficient. Shortly after, Ohio introduced a $300 annual tax on plug-in hybrids, to recover lost road taxes from people with electrics who don't pay their fair share of gasoline tax.) Now my friend spends more on this annual tax each year than he saves in gas.



With due respect your post is idiotic. I've done construction and home remodeling for most of my life. That would include occasionally remodeling homes that were built in the 30's, 40's or 50's. 

1. I can tell you that what once was considered sufficient or acceptable is no longer acceptable today. Take electrical practices as one example. Where efficiency is concerned, had folks taken your advice we wouldn't be using insulation today.

2. You know nothing about my circumstances or considerations, so you are speaking from a point of ignorance. 

Now, if you re-read my original post I asked if anyone had any tankless water heater recommendations or_* "INPUT".* _I haven't made a final decisions in regards to a tank-less unit because I wanted input from people who have and what the pros and cons are in order to make an informed decision.

I'm considering whether I can get one at a discounted price because it wouldn't be worth considering at retail. I am considering whether I would need to install a filter system and the cost of that as well. I am also considering whether an 240v electrical upgrade would be necessary or whether 120v would be sufficient for a shower.

Irrespective, I can build an inexpensive and aesthetically pleasing pre-heater for our hot water system that could significantly reduce our gas bill. I believe it has the potential of cutting our gas bill in half in fact. If I then installed a point of use tankless heater at the one shower everyone uses, I could save even more on utility bills in addition to a significant amount of wasted water.

So these are all things that I am considering. I appreciate folks sharing their experiences and giving advice but uninformed responses such as you chose to make is simply a waste of time for everyone.

Take care,
Ralph


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## user_12345a (Nov 23, 2014)

There are high efficiency tank style water heaters out there - almost as efficient as tankless with less complexity. I think they're in the 80 to 90% range once standby loss is considered.

But even those are often not worth the extra money in a lot of cases. 

If heating water is 20% of the gas bill, going from 60% tank to 90%+ tankless won't save much if anything, looking at total cost of ownership.

Now it sounds like you're set on tankless - let us know how it works out and how much it saves.


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## Ralph III (Oct 7, 2011)

user_12345a said:


> There are high efficiency tank style water heaters out there - almost as efficient as tankless with less complexity. I think they're in the 80 to 90% range once standby loss is considered.
> 
> But even those are often not worth the extra money in a lot of cases.
> 
> ...


 No, I'm not set on tank-less at all but I am doing my homework. Some folks love and swear by them and that is a fact which is contrary to how others feel about them. So there are obviously good and bad aspects to consider irrespective of what some folks may believe.

Worst case scenario I end up not saving any money at all. However, we still end up with instantaneous hot water at the shower which is something we don't have at the moment. As it stands, we have quite of bit of wasted water and wasted energy for each shower taken.

God Bless,
Ralph


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## Photobug (Jun 25, 2017)

When I built my home 20 years ago I wanted to go tankless but the technology was not there yet. 2 years ago I wanted to do it but because my ground water is so cold here I would have had to install two of tankless heaters to get decent water pressure.

The other concern is the water is very hard where I live meaning the system would need to be flushed on a regular basis. Not a problem when I am living here but my home has been a rental in the past and might be in the future. I did not want to have to pay a plumber to come to maintain the system when I am not around.

So I ended up installing a high-efficiency power-vent gas water heater. As some have alluded it may have been a better investment for the long haul installing a cheap electric heater, but I am willing to invest in something more efficient, who knows when the next energy crisis may occur.

If you have a warmer ground water temp, and not so hard water or willing to do the required flushes, a NG tankless would be a nice upgrade in my opinion.


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## iamrfixit (Jan 30, 2011)

Ralph III said:


> Worst case scenario I end up not saving any money at all. However, we still end up with instantaneous hot water at the shower which is something we don't have at the moment. As it stands, we have quite of bit of wasted water and wasted energy for each shower taken.
> 
> God Bless,
> Ralph



I all but guarantee you aren't going to have instantaneous hot water. Even with an electric water heater close to the shower, the unit it still going to have some start up time, from the time flow starts until the water reaches set temp, then a few seconds for the flow at temperature to stabilize.


The only way you're going to get instant hot water is to add some kind of recirculation. That might add a little convenience but it also comes with higher operating costs and added wear on the unit.


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## iamrfixit (Jan 30, 2011)

Photobug said:


> When I built my home 20 years ago I wanted to go tankless but the technology was not there yet. 2 years ago I wanted to do it but because my ground water is so cold here I would have had to install two of tankless heaters to get decent water pressure.



How cold is your ground water? My winter water temps can get down to the low 40's and my gas unit has no problem getting to 120F set point for multiple points of use. It definitely has more capacity with warmer summer water temps but can still easily produce more than enough hot water through the winter to satisfy our household. 

Most power vent tank style water heaters are not really high efficiency. They don't have a secondary heat exchanger to extract additional heat like high efficiency furnaces do. They're basically a regular gas water heater with a vent fan mounted on top. They can only vent using PVC because they draw in additional room air through vents around the fan assembly, the additional cool intake air lowers the vent temp enough to allow PVC to be used. Since they're drawing extra room air out, they may actually make the house less efficient in the long run. Unless your gas water heater is a condensing type, (producing condensate that has to be drained away) it's not high efficiency.


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## Photobug (Jun 25, 2017)

iamrfixit said:


> How cold is your ground water?


I will test it and let you know. The final straw in me deciding to not install a tankless water heater is our water hardness. I am trying to make my home as low maintenance as possible and the need to flush the tankless heater combined with other factors.

I went with the powervent. Reason being was I wanted gas and did not want to have to get a roofer to plumb it through the roof. In retorspect i wish I hadn't installed the powervent, it is the loudest appliance in the home.


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## Ralph III (Oct 7, 2011)

Well, I appreciate all the input guys and it has been helpful! 



Like Photobug I had considered a tankless unit decades ago but I didn't feel the technology/system was robust enough at that time so stayed away from them. Apparently there has been little improvement in that regards and considering Iamrfixit's point I am leaning against getting one now as well. 



I have come up with a very cost effective and aesthetically pleasing solar pre-heater system though, so I will concentrate on that for the moment. That will be a fun project which will increase our hot water capacity quite a bit. I have a quality circulation pump with built in timer that only costs pennies a day to operate that I can use to circulate water at the shower. So that will solve the wait time at the shower and we should see some savings with the extra hot water capacity. 



Take care,
Ralph


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## raylo32 (Nov 25, 2006)

One thing I tried for my similar problem was one of those kluged recirc systems you can buy at the box store for retrofit for when you can't run the lines for a real recirc system. These have a low flow pump that goes on your water heater outlet and you install a bypass line with a temp controlled check valve at the most distant faucet. The valve allows the water to circulate between the hot and cold lines back to the tank essentially keeping the water in the hot line warm and ready for use. In my setup the pump wasn't even really needed, once a temp differential was established it worked with or without the pump being plugged in. 

It is actually a pretty clever idea but in the final analysis didn't work for my purpose. There are a couple of problems with it. First, the temp setpoint is about 108 degrees or so IIRC... which is fine if you want to wash your face or brush your teeth but not for a shower. After the system has been installed for awhile and reaches equilibrium that temp regulating valve just cracks open a tiny bit once in awhile to keep it there and the hot water line back to the tank cools a good bit. So I would have to run off almost as much water out to get real hot water to the shower.

Another issue was that you don't really have cold water since that line is populated with the warm water returning to the tank. Not really a big deal but sometimes you want cold water without having to run off all the warm water in that line.

And the last problem was that in a retrofit like this is that the water lines behind finished walls and floors are not insulated so add heat to the house. This is a small effect and basically a wash... the heat helps the furnace in the winter and hurts the A/C in the summer.

As for your original question, I believe tankless are indeed a decent option and the technology is pretty solid. But don't expect a ton of savings even in the most favorable scenario... and for replacing an existing tank unit the elephant in the room is retrofit costs which are probably prohibitive.


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## Photobug (Jun 25, 2017)

Ralph III said:


> Well, I appreciate all the input guys and it has been helpful!
> 
> 
> 
> ...


I have built in a place under my stairs to put in a tank to preheat the water if I ever went tankless. There is a significant wait for the one shower in my home to heat up I'd have to time it, it is really not that long. I think this falls under the category first world problems. I have a recirc loop plumbed into my crawl space but have never hooked it up.

My thinking is with a tankless system a recirc pump would be like using your existing plumbing as a water tank. The plumbing loop would be kept heated and the water heater would need to stay on to keep the water up to temp. It would defeat the purpose of having a tankless system.

One thing I have considered is installing a recirc pump on a circuit controlled by some type of automation. I have Alexa throughout my home and could add a pump controlled by an Alexa compatible switch. I could have the recirc pump go on for 10 minutes before I planned to shower each morning or use a voice command to turn on the pump when I plan on needing hot water soon.

I could spend days designing and installing a system and a few hundreds of dollars to shave 80 seconds off my shower wait time.


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## iamrfixit (Jan 30, 2011)

Photobug said:


> I will test it and let you know. The final straw in me deciding to not install a tankless water heater is our water hardness. I am trying to make my home as low maintenance as possible and the need to flush the tankless heater combined with other factors.
> 
> I went with the powervent. Reason being was I wanted gas and did not want to have to get a roofer to plumb it through the roof. In retorspect i wish I hadn't installed the powervent, it is the loudest appliance in the home.



I had a power vent for 15 years, was almost happy when it finally died. That thing made the most shrill, obnoxious noise when it ran. My tankless is almost totally silent, can barely hear it standing right beside it.


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## raylo32 (Nov 25, 2006)

I did similar with the Watts recirc system I discussed in my previous post. I installed an AC solenoid valve in the temp controlled recirc bypass line and used X10 module to operate that and the pump from a keypad/remote control and by a schedule. If I opened it up say 10 minutes before I needed a shower it worked pretty well since the water in the line wouldn't have cooled down much yet. But the X10 stuff was never all that reliable. Now I have a lot of Alexa control via the TP-Link Kasa app and plug in modules and my recirc bypass line is still in place so perhaps I'll give this a try. Thanks for reminding me!





Photobug said:


> One thing I have considered is installing a recirc pump on a circuit controlled by some type of automation. I have Alexa throughout my home and could add a pump controlled by an Alexa compatible switch. I could have the recirc pump go on for 10 minutes before I planned to shower each morning or use a voice command to turn on the pump when I plan on needing hot water soon.
> 
> I could spend days designing and installing a system and a few hundreds of dollars to shave 80 seconds off my shower wait time.


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## Photobug (Jun 25, 2017)

iamrfixit said:


> I had a power vent for 15 years, was almost happy when it finally died. That thing made the most shrill, obnoxious noise when it ran. My tankless is almost totally silent, can barely hear it standing right beside it.


If I were to install a tankless heater it would have had to have been a power vent model so I would be likely in the same boat with a tankless. The power vent is so loud only because I have been upgrading all my other appliances. My old furnace was very loud. My new furnace is so quiet I only hear it when it turns off.

Once I am finished building, repairing and upgrading all other things in this house I would consider replacing the power vent water heater.

Tap water comes out at 44 degrees, which is 50 degrees warmer than the outside air temps today. That temp may be conditioned by its time in the crawl space though.


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## Photobug (Jun 25, 2017)

raylo32 said:


> Now I have a lot of Alexa control via the TP-Link Kasa app and plug in modules and my recirc bypass line is still in place so perhaps I'll give this a try. Thanks for reminding me!


Something to consider:

Look at the automation functions of Alexa. I was geeking out on the functions, programmed Alexa to respond to "Good Morning Alexa". She would tell me the current weather, the day's forecast, then a joke, then 10 minutes later turn on a switch powering a boot warmer, so when my wife went downstairs to walk the dog she had pre-heated boots.


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## iamrfixit (Jan 30, 2011)

Photobug said:


> If I were to install a tankless heater it would have had to have been a power vent model so I would be likely in the same boat with a tankless. The power vent is so loud only because I have been upgrading all my other appliances. My old furnace was very loud. My new furnace is so quiet I only hear it when it turns off.
> 
> Once I am finished building, repairing and upgrading all other things in this house I would consider replacing the power vent water heater.
> 
> Tap water comes out at 44 degrees, which is 50 degrees warmer than the outside air temps today. That temp may be conditioned by its time in the crawl space though.





My tankless IS a power vent and it's almost totally silent. Only hear a click, sometimes when it fires at full power I can hear a little of vibration from the fan but you literally have to be standing right beside it.

Our water is warming up now but when we have sub zero temps the water gets extremely cold.


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## raylo32 (Nov 25, 2006)

Yes, able to activate scenes via Alexa... or the Kasa app (or whichever smart things universe you are in). Pretty cool, but I have never really used those functions since I just don't have a bunch of stuff to do at the same time.



Photobug said:


> Something to consider:
> 
> Look at the automation functions of Alexa. I was geeking out on the functions, programmed Alexa to respond to "Good Morning Alexa". She would tell me the current weather, the day's forecast, then a joke, then 10 minutes later turn on a switch powering a boot warmer, so when my wife went downstairs to walk the dog she had pre-heated boots.


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## Ralph III (Oct 7, 2011)

raylo32 said:


> One thing I tried for my similar problem was one of those kluged recirc systems....these have a low flow pump that goes on your water heater outlet and you install a bypass line with a temp controlled check valve at the most distant faucet....



This is exactly what I did at our previous home. I ended up removing the system because as you noted you end up with warm water instead of cold water on the cold side of the faucet. 

The pump I used is a quality pump though and it has a built in timer. I can incorporate that at our new home to setup a true re-circulating system. It supposedly only consumes as much as a 25 w light bulb with constant usage. I will only need it to run occasionally during the day so it should cost near nothing to operate it. 



Ralph


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## iamrfixit (Jan 30, 2011)

Ralph III said:


> This is exactly what I did at our previous home. I ended up removing the system because as you noted you end up with warm water instead of cold water on the cold side of the faucet.
> 
> The pump I used is a quality pump though and it has a built in timer. I can incorporate that at our new home to setup a true re-circulating system. It supposedly only consumes as much as a 25 w light bulb with constant usage. I will only need it to run occasionally during the day so it should cost near nothing to operate it.
> 
> Ralph



Some tankless units can have a recirculation system built in. Can be setup on a schedule to only run at desired times of the day. Course that only works if your daily life runs on a set schedule. You can install a separate, dedicated recirculation line to avoid filling the cold line with warm water. Easy job in some houses but with a finished basement or two story it's much more difficult. 

The pump is only part of the energy story, you're going to be using hot water too. The lines will constantly lose heat, and they do so a lot faster than water sitting an insulated tank, so the pump must cycle to keep the pipes and water warm. Insulating the hot and recirc lines is a must, that can also be a challenge in some houses. Recirculating means more cycles for the heater, it will have to run more often to replace the lost heat.


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## raylo32 (Nov 25, 2006)

Mine came with a nice quality low power/flow Watts pump with a timer. That thing was heavy. But in my house the recirc system works just the same without the pump just from the temp differentials and the hot water rising 3 floors and the cold descending. So I took the pump out years ago even before I quit using the system.

I plugged in the solenoid valve awhile ago and got hot water at my bathroom sink as soon as I opened the faucet so I verified that it still works after several years of sitting. Now I need another TP-Link Kasa mini smart plug. I might as well buy several as I keep finding new uses for them.

As for getting hot enough water with this system, if I activate this about 10 minutes before I need a shower the hot water won't be far back at all. Plus at night I can activate it whenever and have warm water for toobrushing and washing... and have a Kasa timer to automatically turn it off every night. The other thing you can do is just remove the temperature regulating valve and let it recirc full hot water. Just be aware that it will come out hot hot hot right away to avoid scalding. I haven't tried that but might in the future.





Ralph III said:


> This is exactly what I did at our previous home. I ended up removing the system because as you noted you end up with warm water instead of cold water on the cold side of the faucet.
> 
> The pump I used is a quality pump though and it has a built in timer. I can incorporate that at our new home to setup a true re-circulating system. It supposedly only consumes as much as a 25 w light bulb with constant usage. I will only need it to run occasionally during the day so it should cost near nothing to operate it.
> 
> ...


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## Photobug (Jun 25, 2017)

iamrfixit said:


> You can install a separate, dedicated recirculation line to avoid filling the cold line with warm water. Easy job in some houses but with a finished basement or two story it's much more difficult.


That is what i have installed in my house. When the plumber was roughing in the house, he asked if I wanted a recirc line, and I agreed. It goes from the farthest point in the crawl space back to the water heater. I imagine if a pump was installed it would not affect the temp of the cold water in the house.

I am pretty good with my system as it is now but one thing my wife pointed out to me is how long it takes for hot water to get to the upstairs sinks, when she wants to wash her face at night, a problem I have never come across.


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