Tankless Hot Water Heaters

Uni R_2

Wait... do you have a boiler? I guess that is a better first question. If you do you should get an indirect. It's better for the environment, it's better for the boiler, it's better for your wallet in the future. Then the big question remains, do you have enough space for a tank?

An important question because:

A tank requires space. If you can't afford to lose the space, then by all means get a tankless.

If you don't have space, you're going to have a machine with a set maximum and a set minimum that is going to be jumping from idle to full throttle any time you move a tap open just far enough.

Standby losses on modern tanks are so low that the claims of tankless mfr.s that they don't have the excessive standy losses are far fetched. They really make those against open flu water heaters with their own built in burners.

You also give up a tankful of hot water should you lose resources. That vent is also going to be a big issue because it will have to get added somewhere.

To me there really aren't any pluses to a tankless other than space savings. Another external vent, another burner full of parts that might fail, minimum domestic flow rates, easily achieved maximum flow rate heat transfer limitations and no real savings over indirects, in fact more costly verses condensing boilers and the fact it is better for the boilers over the summer.

For gas without a boiler, maybe its okay.

Electric tankless units should almost be outlawed. If you get too many of those big mega amp units all sparking off early in the morning at nearly the same time on your street and you'll know why your lights are flickering.

Europeans have these tankless units because they don't have space. These are also easy to shut off. They leave their heat off a lot in some cases where they aren't there each day - more convenient for that, but still, they need the space. Viessmann sells wall mount indirects in Europe. They look kind of like a Vitodens and hang near it. Smaller tank, but probably quite capable attached to the right Vito.

will smith_4

Out with the (not so) old...

Time to replace my hot water heater, and I'm leaning heavily towards a tankless unit. I guess I've gotten to that age where I'm a bit suspicious of "new" products (at least till the bugs are out). What's your take on the tankless units out there? Anyone have preferred manufacturers, warranty issues, reliabilty issues?
Short story long, would you put one in your mother-in-law's house? (the ultimate test of faith in equipment)

realolman

I am thinking they ain't too good

I have no experience with a gas or electric one, but I have a tankless in my 12 yr old v 74 burnham boiler.
I think I am coming to the conclusion that it costs considerably too much money to heat your water with one of these guys.

There is too much stack loss of heat.

I am still in the process of evaluating mine, but at this point I would not recommend one in your oil boiler. I think it is going to end up that I would recommend against one.

ann_4

tankless heater

We have sold rinnai water heaters for around 5 years. Great product. Once the hot water arrives you will not run out. Try the rinnai 2520FFU heater.

Dave Faust

tankless wait

Yes, but it takes a long time to get to the faucet.

hvac-tech

in hot water

1. temp. of your cold water into your home?

2. # bath rooms?

3. you will need outside wall for the tankless & new venting.


4. a new gas line 1" or larger form gas meter to new tankless

5. for " a pay back at 25years. "
Feb. 05 Consumer Report Mag.

6. tankless unit DO HAVE STAND BY LOST.

Pete_24

We have a Rinnai 2520ffu and love it (it must be direct vented).

We don't have any issue with flow to multiple devices. The only thing you give up is instant hot water at the tap, but you gain absolute temperature control and never run out of hot water as long as you don't exceed the flow amount (which we have never exceeded).

As long as you can deal with not getting hot water the second you turn on the hot water then they're great devices and use very little natural gas. Make sure that the hot water device is as close to the devices that need it as possible -- limit unnecessary hot water pipe during the installation.

Biggest complaint about Rinnai is that they only allow authorized dealers to install the units so that they supposedly can train them properly and control quality, but these authorized dealers generally charge way too much because they can.

Scott Gregg

Tankless

The time to get hot water for a tankless is only a couple of seconds longer. This is because hot water migrates some up the pipe with the tank but doesn't with tankless because the unit is always OFF.

Yes they work great. (Stick with e good unit from Noritz or Rinnai)

Yes they save energy. The amount saved is not much over a 50 gallon gas fired tank heater but IS a lot on larger tanks and is a LOT over an electric tank.

If you want the whole scoop go here:
http://profitableplumbing.com/_wsn/page5.html

(BTW...I am about to re-vent a pile of Rinnai units that were vented WRONG by the "trained installer" and will fail if not corrected. It happens, but the Mfg'ers are trying to minimise such things by requiring training.)

Pete_24

Out of curiosity, what did they do to vent it wrong?

Patrick Mullaney

Apartment Building

I was thinking of placing one in my apartment building - 3 units, 6 adults, 3 children - but have been concerned the volume would not be able to handle 2 simultaneous showers and sinks going off, especially if they are 2 floors away. I have the space for one and have the outside wall and a great place to vent - that is not a problem.

Found a bunch of great info here:
1) http://www.toolbase.org/TechInventory/techDetails.aspx?ContentDetailID=599
2) http://www.popularmechanics.com/home_journal/home_improvement/1274946.html
3) http://www.seisco.com/pages/gas_vs_electric.html
4) http://www.hometips.com/help/tan1.html

At this stage, the way my boiler is running, I cannot imagine using it year-round to produce hot water. And, I would never do an electric.

Uni R_2

Indirect

I would actually think that an indirect would be the best thing for your tenants,, your boiler and especially your wallet. Quick payback there...

mp1969

Tankless On Demand Heaters

I just put a "Takagi" in my house with a "Heating Box" alongside it for my in-floor heat (up to 2000 sq.)We love it and I am about to install my second system for a friend's son in his new house.

There is a reason all the major water heater manufacturers are taking on an instantaneous line. These slick compact units are very viable alternatives if you maintain good water quality.

Also there is a $300.00 tax deduct you can take for installing one of the qualifying units.Yes there are design concerns but if you get past the learning curve you will start designing, installing and using these low mass heat producers!

Rich K.

Make Peace your Passion

Scott Gregg

Wrong slope +

They vented them between 8-15' with the grade back to the heater and no drain tee. Rinnai will condense in the vent on runs over about 5' and this is very acidic. I have seen some units last just over a year like this, others 2-3 but not much longer. Vent Condensate Eats Heat Exchangers!

Also many of the vents stick out the wall as much as 18". The Rinnai vent has an outer wall of thin PVC and it is not UV stable. The sun will rot in a few years and it will fall apart, possibly causing combustion issues.

If the vent is sticking out the wall too far AND graded wrong, it acts like a "Rain Scoop" and water runs out the bottom of the heater when rain is falling that way. (Some homes have both)

None of this is the fault of the Rinnai. It is a fine unit, but it has to be installed properly to get the best performance and life cycle. These issues only effect life cycle. I expect most of these units to have the heat exchanger fail (Leak) within 2 – 3 years unless corrected right away. Some damage is most likely already done but stopping it now will make them last longer.

Again, I like the Rinnai product. There is nothing wrong with it and they work great. I happen to prefer Noritz due to many more options and I think they have some key advantages, however I would never be able to say anything bad about the Rinnai. The big thing with all of these brands is they must installed correctly…Just like a ModCon Boiler and other high tech equipment.

Scott Gregg

Possible Solution?

Assuming 2 baths each unit for a total of 6 showers:

A twin Noritz N-069M or N-069M-DV system would work great.

If you only have one bath units, one will probably work fine and you could always add the second until later if you wanted.

You CON NOT "overshoot" them and get colder water! You get the flow it will give you at your set temperature always.

Mike Thomas_2

Noritz

I went to a factory training seminar and was pretty impressed with Noritz. I have installed one and it went really smooth. Customer is very happy with it. I took considerable time explaining to he and his wife about how it works differently from a regular water heater. He has a big whirlpool tub he wanted to fill and this thing really hit the mark. He dials in the temperature and the gallons he wants on a remote we located near the bathroom. When the alarm goes off he is ready to soak!

Patrick Mullaney

interesting

there is 1 bath per unit and no dishwashers and only one washing machine. How much do these cost and what is the ROI on one versus the existing 50 gallon hot water heater? And, no unforseen issues pumping hot water to the 2nd floor, 3 stories up since this will be in the basement? Any mods to my existing gas line needed and do I need electric supplied to it?? Got a website?

I had a guy give me an estimate for solar hot water, but it was just too much moneny for any potential ROI for the building. Plus, the roof is wayyyyy too steep on this building.

Thanks.

ScottMP

We just installed a Takagi

for a customer with two rentals units in the house. We installed the unit with a 60 gallon Super-Stor. When the tank temperature drops it turns on a bronze pump which creates flow thru the unit and turns on the flame. Nice set-up and they will never run out of hot water.

Considering they had a 50 gallon gas commercial hot water heater with 98,000 input, this should be a real savings.

Scott

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Scott Gregg

Tankless

First your ROI: It ain’t gonna be very big if you only comparing to a 50 gallon atmospheric gas heater. You have to remember you are comparing a unit that can do up to 378Gallons per hour to one that can do about 60 first hour and then has to recover. Plus the life expectancy of 10 years v/s 20. Look at Energy guide stickers and you will see about $176 for the tankless v/s about $190 for the tank…not a big deal in energy for that one.

Your main ROI is not ever running out of hot water and having to get nasty phone calls. Also it will last longer saving you one replacement cost over its life.

Here is a site with loads of info: http://profitableplumbing.com/_wsn/page5.html

If you were comparing it to a 75 gallon gas or and electric the savings add up very nicely to about $190 - $250 per year. Plus, check with your accountant to see if apartments qualify for energy tax credits!

One Noritz N-069M should handle things well. If you can mount it on a exterior wall and pop the vent right through you’ll save on installation too. (Not having to vent through the roof or make a long run.)

Patrick Mullaney

BallPark Me

Scott-

What is the price range for one of these units?

Patrick Mullaney

Product Specs

Scott-

I looked at the product specs for the 069M and would be concerned the GPM at a 130 degree setting (3-4GPM) would be insufficient for 2 simultaneous showers or a shower + sink + washing machine. Thoughts?

I plan to read your - http://profitableplumbing.com/_wsn/page5.html - later tonight before going to sleep.

Darrell

I just took out two Rinnai R-53's. The power went out when it was minus 10 outside and they froze and split. One owner said his split in twenty minutes. Neither unit was purchased or installed by a heating professional, let alone a Rinnai trained one. Both were purchased online...one from E-bay and the other from some earth-friendly web-site. One was installed very well...the other needed some TLC to bring it's self image up. This is not really a statement of the relative value of the Rinnai...just a pertinent anecdote. The local rep...statewide...said that there is a fix for the freeze potential. They recommend a pair of solenoids, one NC and one NO, so that when the power goes out the supply water is shut off and the Rinnai dumps it load someplace.

By the way, I believe that the warranty is void on both units...homeowner installation. I'm OK with Homeowners doing their own work...been there done that...but, most of the warranties will be voided. And so will your homeowners insurance if there is ever a claim even remotely related to the unit in question. 'Course, some "professional" jobs would probably void the warranty too!

Scott Gregg

An Example

At 4 GPM assuming a setting of 130º you are looking at a 75º rise or 55º incoming water temperature. This is where it would be around here for a few weeks in the dead of winter. Our summer time incoming water temps get to 82ºF! The rest of the year there is a “curve” of sorts on public water. Right now it is 67ºF. So at a setting of 130º we have about a 65º temp rise and the unit would put out about 5GPM.

Typical showerhead at 2.5GPM with a hot water setting of 130º is going to use about 2gpm of hot water assuming 0 system pressure looses which is kind of rare. At 130º you will probably use less than 2GPM but I’m going to use that for arguments sake) Two of these showers going would be 4 GPM of flow. If someone turned on the washing machine it would take about 3 minutes to fill and the hot water pressure to the showerheads would drop. (Not the temperature! Just the pressure!) As soon as the tub in the washer is full everything goes back to normal. Hot water temps remained constant and you still can’t run out of hot water.

Lets’ say it’s Thanksgiving weekend, you have guests staying over and everyone is getting ready to go out. You have a 75-gallon tank water heater and just ran a load of clothes and the second set of dishes from the big dinner the night before, uncle Joe gets in the shower and Mom gets in another one. As soon as they get out you get in and your wife gets in the other one. You both run out of hot water towards the end. (If you had a 50-gallon you were out after the second shower) You may still have 2 or more other people who now have to wait to shower. If you had a tankless you take 100 showers like this and not run out. Want to fill up the soaking tub? Your out or almost out of hot water once it’s full with most tanks, not a tankless.

In northern climates you very well might notice more pressure drops with multiple fixtures in the winter however you still are not out of hot water and you can’t feed these things ice cubes. In areas where incoming water is that cold tank water heaters are also going to have a problem keeping up with demand. This is why indirect water heaters on boilers are such a great solution up there where hydronics are already in the home! (Or Bock Power Gas and oil fired water heaters)

There are several GREAT solutions to hot water in a house. Tankless is one of them in many locations. That’s my point.

As far as price the good ones are going to start at about $900 give or take, last 20 years on average (Not 12) and there is a measurable energy savings, plus a $300 tax credit.

Scott Gregg

Question

I understand using a indirect with a tankless sometimes, especially up north for a big house or something but for a two unit apartment? It seems like buying a car and then buying a horse to pull it. (Or using the car to push your horse)

What did I miss? If you have one of those wells that kicks out 35*- 40* water all year I get it. If you have 4 - 6 baths I don't. You could use two Takagis instead for the cost of the one with the tank and have no storage / Stand-by heat loss.

ScottMP

Scott

I am up north ( Mass, right on the water ), and I do have concerns about in coming water temperture. I don't know where you are but the price of the tank was just about equal to another unit.

The customer has a good size house with two rental units in it. She DID NOT want to run out or have a loss of preasure. Since the Super-Stor loss is only 1/2 degree or less an hour I think the tank loss is an issiue.

I like the tankless's but have a problem with the delay. It may be just seconds but seems to be minute's . I installed on in a Doctors office for his exam rooms sinks and was Really Suprised at the wait for hot water. You mentioned heat migration up the pipes for tanks as helping with delivery but the delay from the flow switch and fire-up is noticable.

With the storage tank system, I have effecient production of HW, no loss of pressure during peak demand, and fairly immediate supply ( with or without heat migration). I also don't have the " cold sandwich " during multiply use, as the units ramp up and down.

Scott

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Scott Gregg

Got it

Now I get it better. Thanks. So, you paak your caa in the garaage. :-)

If you get a chance begin measuring your year round water temps on both public and wells. I'd be curious to know what they are up there.

Yes, it does take about 2 seconds from the time flow is initiated until the set point temperature is coming out of the heater. Factor that with several feet of pipe that is not hot since the unit is always off and you get 4 - 5 seconds of extra wait.

The northern tier areas and other cold climates are places that have been reluctant to use tankless, however with the low-mass modcons taking over hydronics they are starting to make inroads. I have to try to be cautious in my enthusiasm for tankless on the net knowing that many people here (The website)live under much different circumstances than we do here. (Richmond Virginia area) I have learned a great many things about flow, temperature and hot water because of these things.

One of them is to not get too hung up on the numbers. Meaning that if velocity at a showerhead is good, there is not one person I've ever met that can look at it and tell if it is putting out 2.5GPM or 1 GPM. If the temperature remains constant and hot you don't get a phone call. With most tankless remotes I can measure these flows and it has really opened my eyes. Without that or a bucket test most of us assume that a 2.5GPM showerhead that was rated in a lab under 80PSI with no system pressure losses is putting out 2.5GPM. “Bucket test” some with a watch and you will get interesting results. I’ve even seen 1GPM and 2.8 GPM in the same house on two different heads with the valves set up the same and both of them clean and free of debris.

Anyway, here is another great use of a tankless and indirect: Restaurants where the commercial DW needs 15 - 30GPM to the solenoid valve! With a small tankless and an indirect you can meet the need with super high recovery without banking a couple of very big very expensive tankless! Works great. These systems only use about 1.5 gallons per cycle anyway. Of course a Bock BCS power gas also works great as would a modcon with a indirect. The Bock BCS power gas is about the most overlooked tank water on the market and is one hell of a machine. (And it uses a Carlin Burner from your back yard!)

Patrick Mullaney

Domestic Well Temp

Scott-

I am about 30 miles northwest of Philadelphia and my domestic well temp remains about 53 degrees year round. One of the reasons I just installed an open loop geothermal heating system.

My apartment building is another 20 miles northwest just outside of Reading, PA. It is serviced by municipal water. No idea about temp fluctuations relative to the seasons.

This has been a very enlightening thread for me as I toyed around with this idea last Spring. Maybe after my boiler is up and running and my tenants have evenly distributed comfortable heat, I will look into this retrofit. I am going to take a picture of the space tomorrow and ask for some feedback.

Next Scott, I am going to need an "expert" up in this area to do the install!!

mp1969

> I just took out two Rinnai R-53's. The power

> went out when it was minus 10 outside and they

> froze and split. One owner said his split in

> twenty minutes. Neither unit was purchased or

> installed by a heating professional, let alone a

> Rinnai trained one. Both were purchased

> online...one from E-bay and the other from some

> earth-friendly web-site. One was installed very

> well...the other needed some TLC to bring it's

> self image up. This is not really a statement of

> the relative value of the Rinnai...just a

> pertinent anecdote. The local

> rep...statewide...said that there is a fix for

> the freeze potential. They recommend a pair of

> solenoids, one NC and one NO, so that when the

> power goes out the supply water is shut off and

> the Rinnai dumps it load someplace.

>

> By the

> way, I believe that the warranty is void on both

> units...homeowner installation. I'm OK with

> Homeowners doing their own work...been there done

> that...but, most of the warranties will be

> voided. And so will your homeowners insurance if

> there is ever a claim even remotely related to

> the unit in question. 'Course, some

> "professional" jobs would probably void the

> warranty too!

mp1969

Heating Box

You want to go to: www.NavienAmerica.com (Google search works best)and check out their on demand add on unit.

This product is fairly new and gives you all sorts of options for your on demand gas fired heater.

It gives priority to the domestic use while providing up to 80,000 BTU's for space heating.

The hydronic side could also be used for a remote indirect storage tank if one is needed for domestic hot water load.

This product comes as an open system (where water separation is not required) and as a closed loop system (in areas where the domestic and hydronic must be separated)

This product is a major labor saver and quite easy to install alongside your Rinnai, Noritz , Takagi etc.

I have installed two units and I am so impressed that I am looking to become a rep for this company. The customer service has been curteous and prompt to reply.

The only problem I have had was finding a stocking wholesaler as the product was just introduced in January.The engineering and layout of components in this heating box is amazing!

You can contact them at 1.800.519.8794 (tell them Rich from Wisconsin recommended them)

I showed this unit to Dan at his hydronics seminar in Milwaukee.If I become a rep I will be advering and promoting this product on this site.

The combination of this "Heating Box" with a properly sized Rinnai,Noritz, Takagi etc. gives you the lowest mass heating system currently on the market.

This system has a terrific future and tankless technology is here to stay.

Contact me: rkontny@charter.net if you have any questions??????

I will (with my wife's assistance) be posting pictures by Thanksgiving.

Enjoy your Holiday!

Rich Kontny

Patrick Mullaney

Municipal Water Temp

Talked to the plumber at my apartment building in a municipal borough as they are replaicng the water main in to the house today and asked him the water temp question.

He said the temp did not fluctuate as the water pipes are running 3-4 feet under ground and the temp is a pretty constant 52 degerees.

Have not verified this via a 2nd source.

Elmer Fudd

Tankless Domestic Water heater

I am considering getting a tankless hot water heater for my house. I agree that a well insulated tank heater will save as much with less hassle but I have a small mechanical space and could use the extra room, putting anything outside in my climate is out of the question.

I am more concerned about minimum flow than sizing for maximum flow. I have been reading about more problems with low flow for the tankless. for example washing your hands, you turn on the faucet the flow is to low to get hot water, you turn up the faucet hotter and the flow starts but it is now to hot so you turn it down and it gets cold again. I have read about the same problem with showers. this may even be worse with low flow shower heads. Again I am not doing this for just energy (even though the tax credit is a bonus) but I would think there is a way to use a tankless with a small storage tank and a pump. It would still be smaller than a a tank, at least it would be on a wall versus some valuable floor space. anybody have any ideas?

Another concern is I have a well with very hard water even after softening. my pressure literally goes from 30 to 50 psi and I am not sure how this will effect the flow in the middle of a shower. also the hard water in the tankless worries me about premature failure. anybody have any experience with this?

Also I would need to have the piping from my propane tank increased to 1".

I am beginning to think the tankless in my case is to much and to stick with a standard tanked water heater and build an addition.

Scott Gregg

Yes.

With all the questions you posed instead of retyping everything go to the website and read the paper. It will anser all of these concerns.

http://profitableplumbing.com/_wsn/page5.html

Low flow is rarely a problem and easy enough to solve.

jp_2

50% savings

boy, i find it hard to believe, a tankless thats 10%-15% more effiecent than a tank delivering 50 % in savings.

Scott Gregg

thats ok

I've seen and heard all the doubts and seen the savings. It's more of an average.

I've seen the extream too!: 2 - 500 gallon electric hot water boilers replace with 2 - Noritz N-080M units in a locker room of a high school stadium in Newport News, VA.

The Natural gas costs for that building for 6-months?...
$27.00 (Not a TYPO $27.00!) They are paid for in less than a year over what their electric bill savings was.

Yes, they are not a HUGE savings over a 50 gallon gas tank type but 50%+ is a real number for larger unit comparisons like a 75 gallon. When get into jobs where twin 75s are needed the savings is way over 50%.

BTW, electric tank water heaters are 100% efficient and cost $450/year on the energy guide sticker vs. $176 for a Propane Tankless. Don't get too hung up on combustion efficiency numbers.