Anyone every use a whole house tankless water heater?

[John Schmidt]

We currently have a double solar panel on the garage roof to help heat the water and it does a bang up job. A week ago I found the water heater tank is leaking somewhere, it's maybe 15 yrs. old so not surprised(perfect timing: Merry Christmas, here's the bill for installing a new water heater). 

The solar water heater is different from a regular elec. heater, it has four pipes running to it, is usually a larger tank(ours is an 80 gal.), and has extra wiring for the recirculating pump sensors inside the tank. Result....a rather pricey item compared to a regular heater. So now I'm looking at installing a single whole house tankless unit in place of it. I can get one for $505 from Home Depot and it delivers 5.3 gal/min. which seems more than sufficient. I'd have to run some new heavier wiring with appropriate breakers but I'm thinking I'd still come out well under $1000....the rough estimate for a new solar tank plus installation. With the tankless unit, I should save some $$ on my elec. bill, something I've always appreciated on the bill with the solar panel, but I'm wondering if it's all that it's cracked up to be. Has anyone on here ever had a tankless unit and did it perform as required, especially with company? Only extra bad part about it is I'd have to patch up about eight holes in the garage roof where the solar panels are mounted, plus a couple more for the piping.

[JimC]

John
I have been using a Rinnai 75 tankless for 5 years now, and I have been very satisfied with it. My only complaint is that when I turn the hot water on it takes about a full minute before I get hot water to the open faucet. But when the hot starts working, it never stops, it just keeps on working as it is supposed to, so in that respect it is great. It is just my wife and I using it, but I am sure when sized properly it will work fine, I have taken a shower while the dishwasher and washing machine were running and never had an issue.

As far as $$$ goes, I did not have a standard type in this home prior to the tankless, so I can not give you an actual savings over the standard water heater. One thing I would check into is the exhaust venting, it cost me almost as much to vent the unit as it did to buy it, but where you are you may be able to mount it outside and eliminate that part.

To be honest, I doubt that you will save anything when you compare solar and tankless though, the sun keeps shining and it is free once the system is hooked up.

Jim

[scooperhsd]

Doing a whole house electric is going to USE electricity - figure on 4-5 40-50 AMP 220V circuits. I'm using a 1 GPM tankless in my kitchen - and it uses 1 50 AMP 220V circuit..

Most people using tankless use gas - either propane or natural. Even at that - these take larger than normal.

[Steel cowboy]

Out of all the instant hot "water heaters" I've seen, I've never seen one last as long as a tank unit. They are great as an auxiliary unit under the sink or next to the jacuzzi tub, on the other side of the house. That way you don't have to run the faucet for a minute to get hot water. Solar hot water systems heaters will use a larger tank than a standard to hold more water since the collector is not that efficient. It's basically just a helper to the water heater to maintain the temp in the tank. In earlier days there were ECU units that worked off the AC condenser unit outside. They used the hot freon going back outside that had absorbed the heat out of the Evaporator in the air handler, to heat the water that was pumped thru it back into the water heater. They could raise the temp in the water tank by 20 degrees. Today's units loose efficiency (SEER) when coupled to them.

[John Schmidt]

As far as running water for a bit before getting hot water, we have to do that anyway...especially in the master bath since it's at the opposite end of the house. Generally, if the tank is working properly(which it isn't at the moment) in conjunction with the solar panels, the water coming out is really hot...especially if it's sunny out. Our shower has a single faucet control and I have to have it slightly to the cold side when all is working right. At the moment, it's being turned more to the hot side due to loss of efficiency and some water at the tank. I have a semi-retired plumber neighbor that I'm waiting on to come and check things out, he usually has a lot of time on his hands but has been quite busy the last few weeks. Guess he's OK with it....just bought a car for his college age son. If he can replace the existing tank for a decent price including labor, I'll probably go with it. Kinda a puts a damper on Christmas spending, I wanted to make this year rather special since my wife was in a nursing home last year and there's no guarantee for the future. I'm putting a new 43" flat panel TV in the master bedroom for her since she spends the majority of her time either resting or sleeping now. But I sure could do without the extra expense of the water heater at this time.  

[cookiedough]

Here is my experience and opinion having for 20 years a tanked water heater that finally leaked 4-5 years ago or so and went with a tankless gas water heater.  

Pros:  save about 20 bucks per month on gas bill tops, if that.  The tankless units are suppose to last 25-30 years as is most made nowadays tanked gas water heaters are junk they will NOT last any of them over 12-13 years more than likely due to inferior too thin tank walls that will leak sooner as compared to the tanks made say in early 1990s and older were better constructed.thicker to last longer.  Not just me saying that, verified with a few plumbers in my area all said it is true.  So in reality my near double pricing for tankless should pay for the difference if it lasts 25 years as they say it should, will see I guess?

Cons:  my initial cost was near double over 2K vs. say 1K for a very nice tanked gas water heater installed.   Yes, it does suck to have an extra 2-3 minutes of COLD water doing dishes or taking a shower, especially here in WI in winter takes a little longer to get HOT in the cold.  We do dishes by hand and if you do not keep the water going slowly doing dishes keeping the tankless unit gas running constantly the water gets COLD not staying warm and then having to wait and wait just to get dishes done needing hot water preferably.  PLus, our unit must not be big enough (go bigger if you can on tankless unit) since if doing the laundry filling up the washer with hot/warm water then the shower if taking a shower is NOT fully HOT just luke warm if running 2 or more high volume needed of HOT water.  We just learned to live with it and not take a shower same time as doing laundry.  

If I was older say in my 60s not expecting to live the next say 15 years or so, I would just go tanked gas water heater and save the extra 1 grand it will cost you on a tankless gas water heater.  If young in the 30s or 40s, then I would go tankless gas water heater which is what we did since if what they say is true, the tankless gas water heater if lasting near double will more than pay for its more upfront cost plus 15-20 bucks or so tops per month in gas savings, coming from a family of 4 in the house with kids taking lots of showers and LONG showers and more laundry as well.  It does save some on gas have noticed that, but not enough to really make a HUGE difference but in 15-25 more years, it does help in the long run.  

Plus, we got an energy tax credit on our income taxes for a home efficiency tankless gas water heater that the model we got qualified for cutting some of that more upfront costs away.

[Cracker Jack]

John, you mention wiring so I assume you are talking about an electric unit. You say the one you are looking at at Home Depot is rated for 5.3 GPM. 5.3 GPM at how many degree rise? The heat input is a function of watts, volts times amps in this case.

Electric water heaters are rated in watts. One KW will raise a certain flow rate a certain rise in temperature. I don't know off hand what the multiplier is.

To determine the wattage you need, you need to know what flow rate you need and what rise in temperature you need. For instance, to supply one shower alone with a 2GPM shower head and you have 60 degree water into the heater and you want your shower to be 110 degrees (without any heat loss from heater to shower), you need a heater to provide 2GPM with a 50 degree rise.

The heater mfg. will provide a chart to show the available rise for various flow rates. The flow rate you use to size your heater should include the total flow you plan to use at any one time.

The link below indicates that for your area, you should plan on inlet temp of 67 degrees and to run two 1.5GPM showers at 105 degrees (38 degree rise), you need the 18KW model which is good for 3.2 GPM.

https://www.ecosmartus.com/product/ecosmart-ECO-18-18-kW-Electric-Tankless-Water-Heater

[firemedic309]

tankless waterheater out of Sarasota 

[Hook#3287]

I built my house in 1990 and installed a top of the line tank gas 50 gal water heater. 

It lasted about 7 years due to hard water, even with a water softener.

I installed a gas tankless and have been totally happy with it.

It stopped working a couple of years ago and I figured I got my money out of it, started looking at replacements.

I decided to see if I could find what was wrong and discovered a wire connection had corroded.

Cleaned it up and she's been running fine since. ( probably just jinxed myself)

If you have a natural gas line it's a no-brainer, I'd even go tankless if propane is available.

There's a learning curve with tankless, but you get used of it.

[robin]

I had a tankless in my house and lasted 30 years it was a Poloma i did put in a water softener to take care of iron.You can put multiple ones to take care of different parts of the house upstairs,downstairs if ya have just one you will need to do one thing at a time but ya get used to it.

[da prez]

  I am not jumping in with my limited knowledge of tank less , water heaters as we just started thinking about them for our house in northern Wisconsin. Reading this , I may pass on them. Until we use it as a full time home , it is shut down and winterized.
  The wonderful thing about this board is the vast knowledge that exists.

                                         da prez

[cookiedough]

  I am not jumping in with my limited knowledge of tank less , water heaters as we just started thinking about them for our house in northern Wisconsin. Reading this , I may pass on them. Until we use it as a full time home , it is shut down and winterized.
  The wonderful thing about this board is the vast knowledge that exists.

                                         da prez

agree, not worth the expense if not using it near daily.  I say in the long run if a single family home and not too large of a home, go tankless gas if planning on staying in the home (or living) say another 20+ years.  If not, just take your chances on a gas tanked water heater and hope it lasts 10-12 years.  My moms in her house was installed new way back in the late 1970s and still works but they were made better back then and am sure there is so much lime/deposit buildup all over that it cannot leak that is what is holding it together, but is only 1 person the last 10 years or so not much use.

We had to install gas lines and exhaust out back.  One thing for us cold northerners is the exhaust can be tricky and 2xs when BITTER cold here in WI say -10 below Fahrenheit with HIGH winds wind chill readings say -30 below,  the strong winds have come thru our exhaust vent and froze up (frost layer) the internals of our gas tankless water heater a few nights since wife showered in morning (she was pissed) and was a code reading on the unit not working.  I just had to take a hair dryer on high and take off front cover to thaw things out for 10-15 minutes, reset unit, problem solved.  Poor design and mfg. knows this but refuses to provide a remedy/solution.  I put up an old BB hoop backboards in front,  but NEVER too close to the exhaust say 3-4 feet away to help block some of the wind from entering in the wintertime, seems to help if needed the 1-2 times every winter it did it the first year.  I once set BB hoop backboard 1 foot in front of exhaust only  and NEVER do that since backup exhaust pressure was shaking and shuddering unit/pipes,  VERY dangerous am sure.  Luckily I was home and heard something shuddering in basement and figured it out ASAP.

It does take some getting used to since for sure running 3 hot waters will probably not work fully HOT just luke warm water.  I set mine at 120 degrees since can take HOT showers fully HOT near cranked up all the way HOT.  I tried 110 degrees full blast on HOT and not HOT enough.  115 degrees would probably due but if running washer and shower same time,  best to go up 5 more degrees without burning yourself still. 

As said, longevity of where the HOT water goes makes a HUGE difference.  Our hot water heater is in one corner in basement and has to flow up one floor into the shower located guessing 40 feet away tops.  If I had 3 level home vs. single ranch with full basement, I would be skeptical on if only one gas tankless water heater would do the job in a much bigger home as well.  Now running 2 showers at once you would for sure have to get the BIGGEST unit available to keep up the demand of HOT water.

[scooperhsd]

Ok  - more amplification -

I AM using a 9.5 KW tankless in my kitchen, because of the long run from the electric tank water heater (well over 60 seconds to get hot water without the tankless). This heater takes a 50 AMP 240V breaker by itself, and mine is one that has a thermostat so it can take the "hot water" input. Given it's intended use, I have the tankless set on 135-140 Degress F. It also supplys 1 GPM at the temperature rise I need - it works fine as a kitchen source, but it is not large enough to run a shower or the laundry.

We use an electric 40 gallon tank for regular uses - I either just let the cold water in the laundry or if I want a hot water load - pre-run the laundry room sink until I have hot water.  If it was a real big deal, you can get recirculating pumps that will return through the cold water lines.

John , If it was me - I'd either just replace your tank or put an electric tank type in (who says you have to hook the power to it ? ), whichever is cheaper. Or you could put a gas tank type WH in.

[John Schmidt]

The link below shows the unit I was investigating, a 27kw electric. As for life span, I'd love to see if it would actually last another 20 years. Problem is, I most likely won't....that would put me about 3 months shy of 100 years old and my chances of living that long aren't all that great. Looking at it from a total work and financial outlay, it would appear just replacing the old tank is probably best. If I went with a tankless unit, I would have to patch 10 holes in the roof after removing the old solar panels and pulling all the piping out. Then add the cost of additional wiring for the elec. load of the new tankless unit. I have to tell another story on a new post, takes up some room. 



https://www.homedepot.com/p/EcoSmart-27-kW-Self-Modulating-5-3-GPM-Electric-Tankless-Water-Heater-ECO-27/203316218?MERCH=REC-_-rv_search_plp_rr-_-NA-_-203316218-_-N

[Jess Tolbirt]

there is no such thing as a hot water heater

[John Schmidt]

Au contraire mon frere. On the not so sunny days, the water from our solar panels comes into the tank at under 100 degrees, at which time the hot water is then heated to the setting on the controls. Hence....a hot water heater since the water is already hot, just no hot enough. As is often the case, all depends on one's perspective. 

[Crackerborn]

While I limited personal experience with the tank-less water heaters, I have a client that converted an old school house to a 16 unit apartment and he used natural gas tank-less water heaters in all the units despite the plumbing contractor attempting to dissuade him. Two units leaked in the first month, one leaked(?) immediately (the heating coil was improperly soldered) another failed without leaking within 3 months, 3 others failed in the first year (one was a warranty replacement unit). Yes they were under warranty to replace or repair the water heater but they would not cover the damage caused by the faulty units which was extensive. Wood floors and drywall ceilings in 5 furnished units as well as putting the tenets up somewhere while the repairs were completed was an expense that dwarfed the cost of the tank-less water heater units. The entire building now has conventional tanked water heaters with floor drains under each water heater and it was initially finalized for occupancy less than 2 years ago. The tank-less water heaters were manufactured by Rheem under another company name and as a result of that fiasco, I have steered all my clients away from any Rheem product.

[gordonv]

I researched them about 10-15 years ago, when I needed a new elect tank.

You can put multiple ones to take care of different parts of the house upstairs,downstairs if ya have just one you will need to do one thing at a time but ya get used to it.

I understood that in Europe (Holland, where family is), they use multiple heaters beside the place they are being used. No single source.

We use an electric 40 gallon tank for regular uses - I either just let the cold water in the laundry or if I want a hot water load - pre-run the laundry room sink until I have hot water.  If it was a real big deal, you can get recirculating pumps that will return through the cold water lines.

Actually a recirculating pump should move the hot water through the whole systems, back to the tank. This way, the water in the hot line is close to the tank temp.

Then when a hot tap is turned on, it draws it from the already hot hot line.

I don't know how good this would be in an existing home. I would want the hot pipes covered with insulation, to lesson their heat loose, and not warm the walls/house.

It's been a long time, but I don't recall which was better tank-less, gas or electric. I think electric. The retro fitting of your home, only you can answer that question, maybe what will cost you the most (gas fitter/electrician, venting, etc..).

[John Schmidt]

To start with, no natural gas available in this immediate area, only LP. And the only place to put a tank of LP is outside our bedroom window....which ain't happening! 

[Titan]

For those of you who have to wait a while to get hot water to part of the house, take a look at this pump. I’ve had one under my kitchen sink for years. Primarily, it pulls water through one pipe and sends it back out the other to the water heater, thus not wasteung all that water that you would be running down the drain. It gets the hot water to you faster. It’s activate by a momentary push button switch that I installed in the counter beside the sink and it stops pumping when it senses warm water.

http://www.chilipepperapp.com

[gordonv]

Here is the info I saved, from this web site.

http://www.finehomebuilding.com/?s=hot+water+on+demand

Check out the one on the recirculater.

http://www.finehomebuilding.com/2010/11/11/hot-water-recirculation-systems-how-they-work

A lot of info on this site.

[_Sheffjs_]

Tankless but natural gas. 

[solo1]

I learned something.  The retirement apts where I live use the gas water heater to heat the apt.  We have the usual trouble of running the water until it gets hot. In addition temp varies depending on the apt heat requirement. 

The big problem is that our town's water and sewer rate is based on water usage. Cost is super high because of federal mandates.  The apt. owners pay the water/sewer bill. as a result, my rent has sky rocketed since they pass along the costs.  TheChilpepper recirculating pump ,as noted here, might be something to cut down the cost and usage of water and sewer..  good idea.

I'm going to pass this info to the owners.  TNX

[¿spoom]

Hopefully not too late to matter, but I got to talking with a retired plumber at the diner this morning, and brought up the details as I remembered them. He said his first research would be the condition of the solar panels and their plumbing to the residence, including age of the electric pump and the roof itself regarding any upcoming repairs or even the PITA quotient of getting at the roof shingles if overdue for replacement. Then, he said it might be time to think back to anything you really liked/disliked about the current setup, including waiting for hot water when a tap was turned on and overall usage/recovery time. Since your system is electric, he said you might be better off scrapping the solar system IF it's near the end of it's overall life and going with the tankless so you're not paying a dime for anything (including circulation pumps) until the second you turn on a hot water tap. He said if you have high enough service to the house and locations far from each other like a bathroom or laundry area at one end and kitchen  on the other, you might even consider two point of use electrics, sized according to GPM needed. He said even with a dishwasher, most kitchens actually can get by with a small unit, and that washing machines can do such a good job on cold settings that they only use a little hot water during the soap dispensing minutes at the beginning of a load, with the bathtub/shower being the REAL hot water hog.

[1NorthRyder]

I have a dual purpose on demand boiler that supplies the heating for the entire house (2700sq,ft.) and Garage (1000sq.ft.) as well as all domestic hot water. Cheapest utility bills I've ever had and works fantastic. The fact that you are pre-heating the water with solar is that much better.

[Jabba]

3413 BTU/KW

BTU = 500 x GPM x Temp Rise

Do the math...

Jabba

[Ramie]

I learned something.  The retirement apts where I live use the gas water heater to heat the apt.  We have the usual trouble of running the water until it gets hot. In addition temp varies depending on the apt heat requirement. 

The big problem is that our town's water and sewer rate is based on water usage. Cost is super high because of federal mandates.  The apt. owners pay the water/sewer bill. as a result, my rent has sky rocketed since they pass along the costs.  TheChilpepper recirculating pump ,as noted here, might be something to cut down the cost and usage of water and sewer..  good idea.

I'm going to pass this info to the owners.  TNX

They sell under the sink hot water recirculating system for as low as $200. 

[Jess Tolbirt]

Au contraire mon frere. On the not so sunny days, the water from our solar panels comes into the tank at under 100 degrees, at which time the hot water is then heated to the setting on the controls. Hence....a hot water heater since the water is already hot, just no hot enough. As is often the case, all depends on one's perspective. 

thumbs up!

[BudMan]

We have a (LP Gas) Rinnai Tankless and it has performed flawlessly for 14 years now. I did plumb it so I can isolate it and run vinegar through it once a year to deal with the accumulated scale in the heat exchanger.  The hot water is instantly up to temperature leaving the unit but like all non circulating hot water systems, the cold water in the pipes must be expelled prior to the hot water arriving at the outlets.

[cookiedough]

We have a (LP Gas) Rinnai Tankless and it has performed flawlessly for 14 years now. I did plumb it so I can isolate it and run vinegar through it once a year to deal with the accumulated scale in the heat exchanger.  The hot water is instantly up to temperature leaving the unit but like all non circulating hot water systems, the cold water in the pipes must be expelled prior to the hot water arriving at the outlets.

do you feel it is necessary to run vinegar in a 5 gallon bucket with hoses thru the unit EVERY year?  I have only done it once in 5 years now and thinking it should be done again.  I did it at 2-3 years and the vinegar was pretty clear still running it for near 1 hour with a sump pump/hoses not too discolored.  Thinking it is time again.  installer said once every 3 years is fine, agree or not? 

[Stanc770]

I recently had to replace an AO Smith 50 gal hot water heater at 15 years of use. No complaints about the time of use or quality. I installed a circulation pump on my system years ago that is simple to install and has only two parts, the pump and relief valve in the farthest place where is water needed from the heater. Circulation pump (Watts), is less than $200.

My neighbors on either side of me went with the Rannei Tankless systems 3-4 years ago and have the same issues of long wait times for water to get to the farthest point in the house and not being as hot as they want.. I spent roughly $700 for a new professional duty heater and it took about 2hrs to drain and install. My neighbors had to have gas and vent lines run and they spent on one house $4700 and $5100 on the 2nd house. The difference was they used different plumbers. I believe the ROI is in my favor due to they still had to have circulation pumps and when the tech came out to service the tankless unit (whole house), it was expensive.

When the technology catches up, I will probably go tankless when I need another heater, meantime I’ll look forward, based on past experience, of 15 years of not worrying about it.

The. Smaller units fit for sinks may be the answer and they are electric.

[¿spoom]

I think the technology is already available, as the US is about the last major country in the world that still heats a tank of water 24/7 instead of point of use. I'm guessing they have top shelf quality units available from the economy of scale and competition from millions of users, compared to barely being more than a novelty here. 

[BudMan]

We have a (LP Gas) Rinnai Tankless and it has performed flawlessly for 14 years now. I did plumb it so I can isolate it and run vinegar through it once a year to deal with the accumulated scale in the heat exchanger.  The hot water is instantly up to temperature leaving the unit but like all non circulating hot water systems, the cold water in the pipes must be expelled prior to the hot water arriving at the outlets.

do you feel it is necessary to run vinegar in a 5 gallon bucket with hoses thru the unit EVERY year?  I have only done it once in 5 years now and thinking it should be done again.  I did it at 2-3 years and the vinegar was pretty clear still running it for near 1 hour with a sump pump/hoses not too discolored.  Thinking it is time again.  installer said once every 3 years is fine, agree or not? 

With most normal water conditions, you are probably correct. Our water is quite a different situation.
We're on well water that I had tested. The DEQ, (Department of Environmental Quality) said "if it were just a little bit harder, they would suggest not even bathing in it! We use purchased Reverse Osmosis water for all drinking and cooking. (Sorry for the delay in answering, been doing the HO HO HO thing.)

[Robert]

Interesting thread and well timed for me since I was thinking about a tankless system. The cost of operation is not the thing for me since from everything I have read and researched it does not save that much. Not to mention better insulation of the tank and water temp settings on a conventional, makes it not a big savings. Once you take that out of the equation the cost of install is more. The only savings for me would be space since I would get  an outside unit and not have to have the heater tie up any space and be mounted on the exterior wall.

My hot water runs me about 25.00 to 40.00 a month how much more can I save off this and I even keep the water temp at about 140, since its only at temps this high that help eliminate bacteria in the water tank. It also saves on the washing machine heating water and the dishwasher heating water.

I can change out a hot water heater in about 2 hours and I dont have to have electricity to get hot water and here in S Fla with the power grid its a nice added thought. On the first Hurricane we had my family came to my house since I was one of the only ones that had hot water and was able to cook on the stove. We did have a small generator but that was so nice not to have to take cold showers in a time of stress. This was in the back of my mind when considering a tankless system and even a tanked hot water system since some now require power to run the efficiency gadgets mounted on them. 

If you have gas and call the gas company they do offer discounts on gas appliances sometimes and this could offset the cost of any appliance you install.

I did recently install a whole house water filter system and found that it was a good investment. Not only for the water quality but for the life of appliances and plumbing. It has a carbon and sediment filters that filter to 1 micron and remove all the chlorine and minerals that help to cause scale. I had at one time a washing machine valve go on me and I wonder if it was from the sediment in the water. We do have decent city water but I did notice that a glass of water went from a slight tinge to totally clear.

All my running expenses on my house are not that much, electricity for the ac or heat being the biggest expense. With the advent of LED's for lighting and appliances like tv's and most items that you have are not running real power but using small chargers the cost has gone down quite a bit. I did re insulate my house a couple of years ago and that saved about 50 a month off my electric bills along with a new ac unit.

All the promises of lower electric bills or gas bills when switching to me is almost like all the claims for add hp when bolt on items. I wonder how many here really know the exact cost of their hot water since its usually hard to separate out the cost of one appliance on electric. Mine is gas and I do have other gas appliances but the heater is probably the biggest user so its easy for me to see the cost. 

I have to curb my enthusiasm for shiny new things since I seem to be pulled in that direction, since most claims of added hp or added savings are smoke and mirrors.
 
As for the time it takes for the hot water to reach you most faucets are limited today to 3 gpm unlike the old days that you cold flow as much water as you wanted. So it takes longer for the hot water to reach your outlet whatever that is.

In most high end homes the accepted standard to get hot water is about 10 seconds from turning the faucet on.