I can't help much about the costs. Since we changed everything (2 heat/ac units, cook top, bbq, 2 water heaters and a ventless fireplace) over to natural gas, it's hard to tell. This is our first full winter on natural gas, and I believe it is much cheaper than propane.

I can tell you the space savings is awesome! We had an 80 gallon electric water heater in the new part of the house. It took a lot of real estate on the floor in the utility room. The new heater hangs on the wall, so I gained a lot of floor space (now full of Christmas decor!). My BIL has his behind a panel in his hallway, so you can't even see his.

We had a Noritz natural gas tankless installed as part of our remodel/addition January 2007. Since we live in the south we opted for an exterior installation. It does take a couple minutes during the cold months for the heated water to reach the farthest water source. In our case that's about 50 feet. Closer to the WH it's almost instantaneous.

Here is a link that might be useful: Noritz

We wanted to get one when we purchased our house. The reason why we opted not to get one is because we have very hard water and even with water softeners, the plumbers noticed that they had to replace them more frequently. So, we went with recirculating hot water which helps get the hot water to the upstairs master bath quicker. I also have two 40 gallon hot water heaters, run parallel with one set at a warm setting so that when the water hits the other heater, it is already on its way to hot. If we have company, we just crank the second heater up and we never run out.

We have the identical set up as Natal. Noritz 6.4 gpm. It is gas, mounted as hers is . We get hot water almost immediately except at the kitchen sink and that is only a minute or two longer. I have the adjustable thermostat in the laundry area. i keep it set at 120 degrees in the winter and 100 in the summer. This makes for a large savings as you never add cold to hot water and you don't over heat water only to cool it back down. We have had ours over a year now and love it.We never get bursts of cold water , in fact I think that would be impossible since you would have to have your gas flow be interrupted and I can't imagine how that would occur. Anyway we would never go back and have several folks in the area switch after seeing ours. c

We also mounted the thermostat in our laundry room. It's set at 110° year round.

Do these things hang outside the house or inside? Can it go in a garage? Our water heater is old and ready to be replaced so I'm very interested in the tankless style. We have very hard water and no softener so it will have to be pretty durable to deal with the lime, scale and other deposits the water leaves behind. My dream would be able to have a water softener but there's no space for it ...but if the tankless heater goes outside the house that would free up space for a softener (if it can fit in the same place the old heater took up in the garage). Anyone know how those work together?

I did so much research on this when we bought ours. I chose SETS because NASA helped fix a minor problem for SETS and then they used the units on the World Trade Center clean up doing 200 showers a day. We put in two SETS electric units when we built. We've been in now for 6 months. Our regular sink faucets seem to work pretty good but we have an had an awful time in our showers either getting or maintaining hot water. And if ANY other faucet is on we have no hot water. We don't really know at this point what is causing this problem. But it's really not fun to have nice warm shampoo shower water turn icy cold in a few seconds.
Both tankless units had parts that needed replacing when we first moved in. The SETS company was great up front and we received the parts the next day. We still cannot maintain a hot water flow in our showers. We also had boiling hot water suddenly spurt out in one bathroom sink while it was running cool water but that's only happened once. SETS hasn't responded to my husbands emails about either issue.
In all fairness the problem could be related to sediment from our well. We placed a filter at the pump and also put in a soft water system but still have a sediment problem. Flow is important in regulating these units

The sudden cold water that could occur with a tankless water heater that some of the posters mention is called the "cold water sandwich". Tankless heaters need a minimum flow of 1/2 to 3/4 of gallon (depending on the model) to turn on and start heating the water. That means that if you were to turn the hot water really low it could turn cold. That shouldn't really happen in a shower though because the flow rate is always high enough.

The main consideration with tankless heaters is how many gallons per minute (gpm) do you need at peak times and then get a heater than is rated at least that high (someone mentioned their Noritz 6 gpm heater above. That's a powerful tankless heater. You could run 3 showers simultaneously if you had to.

If your cold water coming from your town or well is lower than 55 degrees that too will have an impact.

One of the biggest considerations for many people who install a tankless water heater to replace a regular water heater is the gas line. (Unless you use an electric one which are less powerful and use a LOT of electricty wher they are on.) Gas fired tankless water heaters require a 3/4" hard gas line. Most standard water heater installations are only 1/2". This could be a small or large expense depending on how far the heater is from where your gas line enters the house.

Jim

Speaking of water softeners -- I don't know the state of these today, but my parents developed heart problems and were told that the water softener over the years was part of the culprit. Whatever the case or accuracy of my memory, it used a lot of salt and maybe do some research on how it relates to heart dz before using or getting one :)

Tankless heaters need a minimum flow of 1/2 to 3/4 of gallon (depending on the model) to turn on and start heating the water. That means that if you were to turn the hot water really low it could turn cold.

And that's exactly what happens. I've been washing dishes in a bus bin in the bathtub for the past year (during construction) and a few times I noticed the hot water turned cold while I was rinsing dishes, because I had lowered the flow.

We have the Takagi tankless water heater. It was initially installed outdoors but after an addition on the house, it became part of the indoors. One of the largest expenses was venting to the outside. You have to use a special high heat ducting that is stainless steel ($$$$). I think it was a little over $1K for the venting alone and that was for a very short run thru the roof.

One problem we had with hanging it outside like the pictures above was that the mounting instructions said it had to be a certain distance from doors and windows because if it wasn't vented thru the roof then whatever gases it gives off could be sucked into your house thru the window/doors. In our old house, we really didn't have any length of wall space that was far enough away from a window or door.

We have one that's rated to handle two fixtures at a time (such as shower/washer, washer/dishwasher, etc). Unfortunately, we do run into the low flow situation where the hot water will cut off and turn cold because the flow is too low to keep it fired up. We can't use a low flow showerhead for that reason. It does seem to me to take longer to get the hot water than with our conventional water heater and they were basically mounted in the same place. It did free up a lot of space. Due to the purchase price/installation costs I would only purchase again if space were an issue.

I don't know if it has saved us any money. My gas bills were not that high to start with. I know it has not saved us the cost difference between a conventional water heater and a tankless and we've had it for a few years now.

We've had a Rinnai for just over a year. We haven't had a single of the issues I hear from other people -- no sudden cold water even with kitchen sink flowing pretty low. We LOVE it. The *only* problem is that if the power goes out, we have no hot water at all until it comes back on (heater is gas, but ignition and power are electric).

No clue how it will hold up long term, but for now we don't regret it a bit. It did cost $$$ (mostly because they had to do a lot of replumbing because the previous job wasn't done right).

One thing NOT to do is to go with the cheap ones they sell at Home Depot. From what I understand, a lot of the problems attributed to tankless heaters are problems with cheap DIY installs.

I think one thing that was mentioned some time ago here about these, is that the part of the country you're in makes a difference, ie, how cold it gets in winter.

Squirrel, that is interesting about the water softener and heart disease ( and I am sorry to hear that both of your parents developed heart disease - my dad and dear MIL both had it as well).

I am wondering how your parents' softener was connected - the one in our home (and the ones in the homes in which I grew up) bypass the kitchen faucet and outside faucets, so the softened water is not used where it is not needed and so the taste is not affected.

Merci beaucoup to all who have taken the time to respond here. I will pass along this thread (and any more discussion that follows) to them. I know it will be appreciated.

We have two propane gas fired Rinnai's. We have had absolutely no problems so far, in 6 months. They are mounted on opposite exterior walls, the gas tank is buried and the water softener is outside too - so NO loss of space inside at all! This set up works flawlessly for us whether there are two of us or a houseful. I can't tell you about cost but we are very pleased with our gas usage.

Les, the softener went waaay back in time, but I'm sure it went through the whole house and seem to recall the water actually tasting better!, lol. The soft water is great, we all loved it, but maybe back then they didn't bypass the kitchen for drinking. ? I'll have to ask my mother and see what she recalls. (She'll probably say she's never heard of such a thing! lol)

Just found something on it. Not meaning to hijack the thread, but in case anyone's interested in health concerns around the water softeners. Apparently it's not just the softeners, but simply hard vs soft water as well.

Discussion

Medical Article

Living in Japan we are very used to tankless water heaters and think they make good sense. We plan to put one in a rental unit in Minnesota that may only be used a few days a month, thus we did not want to keep 80 gallons of water hot for the Japanese soaking tub. I am also wondering about the concern about the "temperature of the water from the well or city." In Japan, the water pipes are not insulated and run up outside the house, thus in the winter the water coming from the faucet can be 40F . We never have trouble getting non stop hot water.

Here's a blurb from Wikipedia, and the link where info on thermodynamics and other things has been contributed.

...Although instantaneous heaters can give a continuous supply of DHW the rate at which they can produce it is limited by the thermodynamics of heating water from the available fuel supplies...color>

Here is a link that might be useful: Check out Thermodynamics of Water

Here you go Les and Cindy, on the affect of region and climate.

Here is a link that might be useful: Tankless Units and Climate

Wow, I'm so glad this conversation is going on; I just put an offer on a house yesterday and the only thing I would change about the whole thing is a huge, space-wasting cabinet in the kitchen that was installed to hide the water heater. Massive kitchen square footage has been rendered useless.

But, since the present heater is on an interior wall, it gave me pause to hear that venting has to go through the roof. I assume this is not the case for electric, just gas?

Does anyone have thoughts about or experience with electric tankless water heaters?

No, it doesn't have to vent through the roof. Our gas tankless is in the basement and vents out to the side of the house. There are "rules" on what can be around the vent and the placement (ours is near a HVAC system and a cooktop downdraft exhaust), but it doesn't have to go through the roof. Check you local codes to see your restrictions.

Betsyo -- We have the exact same problem. I've gotten two estimates so far for tankless -- both external. The first guy wanted soemwhere around $15,000 because he wanted to fur out the exterior wall to recess two Rinnai units and put in 3 control panels. The second guy wanted about $4000 to install a single external Norritz with a recirculating pump and one control panel. The unit would not be recessed in the wall, but would stick out like the pictures in this thread. To me, it just looks like another electrical box, so I don't mind it at all. He didn't think we would need two units with the recirculating pump. I am a bit concerned about the water pressure/hard water issues, but the plumber I spoke with seemed to think that the recirculating pump would solve the water pressure issues. I didn't ask him about hard water.

squirrelheaven -- the water softener we had when I was a kid used salt, but I haven't had one in any house since so I don't know if the technology is still the same.

sara: what size home are you in? How many bathrooms ? We have 4000 sq ft on 2 floors with 3 1/2 baths. I have the laundry area and one dishwasher , Bosch, with an internal waterheater . I am not sure why you would need 3 control panels. If you set the thermostat to 120 then it is not too hot for a shower in cold weather and you need not worry about burns . It is never necessary to change the preset temp. In the Spring when the weather warms up I lower the thermostat on the digital control to 100 degrees and that is perfect for showers til the weather cools off again. This way you never waste energy by overheating hot water then adding cold to temper it. My dishwasher heats the water on up as it cycles. We have a 6.4 gal per minute so never need a second unit. I dont have any recirculating pump and am not sure why/if you need that expense either. If you have the one large unit and one digital control in the laundry area and mount outside then I think your cost should be quite a bit reduced and you will really like the setup. What do you think? c

Uh, er, $15k, $4k -- I'm sure not aware of that little hurdle. I was told it was somewhat comparable to replacing the tank. Sure hope that doesn't nix things over here.

Actually, I could get a decent size storage room at U-Haul for a number of years instead.

$15k?, I agree, that would have blown the idea for me as well!

we briefly looked into replacing our gas water heater with a gas tankless in January. I think the units themselves- decent ones- were about $1000.According to the vendor websites, the vent needed was a 4 inch, whereas the existing vent is a 3 inch. The hole thru the basement wall would need to be widened and it was a lot more to consider than just swapping them out. Certainly not a decision we were willing to make spur of the moment- just because our hot water heater unexpectedly quit in winter. We were lucky enough that the parts came and my DH made the repair on the heater so we have a bit more time to look into this.
We don't want to get one that is not large enough for our needs or will not pay for itself in sufficient time to be worth the hassle. If the cost is prohibitive we will stay with the old tried and true.
Sue

We have a 2500 sq ft California side split level, one bathroom on the third level, one bathroom and laundry on the second level on the same side of the house as the third level bath, master bath on the second level but opposite side of the house, and kitchen in the middle of the second level. The unit would have to be mounted on the exterior wall of the master bedroom where all of the gas, water and electrical meters/boxes are. The traditional gas water heater is currently located in the kitchen, which is why I want to go tankless.

The units cost about $1000. The recirculating pump was recommended to me to solve the problems described above re: slow to heat up in the laundry and the two bathrooms on the opposite side of the house and loss of water pressure. The recirculating pump is electric and costs about $500 for the pump itself. The rest of the costs (wildly different, but both high) are labor, venting, etc. We're trying to get more estimates, but having difficulty getting folks to come out and take a look.

We considered this option as our boat does not fit in garage because the waterheater is in the way. But as mentioned above, the gas line is not right size. We could retrofit as the line is about 5 feet from the meter, but it is just not something we want to do right now. The unit cost was about $1000-1500 depending on size. Hiring the gas man would be a lot. So we repositioned the boat.

We have been in two houses since 1993 and have only ran out of hot water one time that I can recall. Recently I ran the dishwasher, then dd got in shower- she needs a timer- and then I took one. By end of my quick shower, water was luke warm. Since I usually run dishwasher at end of day, this was just a freak co-ink-i-dink.

Sara I am not a plumber or an GC but I do have one of these and can only offer an opinion. Since the unit is going on the side of the house where the MB/MBR are (that is where ours is) then the KItchen is in the center of the house ( that is where ours is) and the opposite side of the house for another bath (that is what we have too) , I can honestly say you don't need the recirc pump. We are talking only a couple minutes at most for hot water and then only in the coldest weather. Also how often do you wash clothes on hot water? I only do whites 1x week so that is not an issue. I sure hope you can get this resolved to your liking. The 6.4 would be way more than you need, I think unless you have more than 3 people showering at 1x. Hope this helps ,c

Hmm. We run laundry of various types on a daily basis these days, but that might slow down once the kiddos get past the occasional wet pants stage. Of course, that doesn't address the adult wet pants issues that are sure to come. :-). Right now, I can't see us having more than 3 people showering, but in a couple of years me and the two kids will be getting ready at the same time each morning, and the laundry and/or DW will likely be going at the same time. The difference in cost between recirculating pump + tankless heater and tankless heater alone was $500, which, while significant, is not a huge proportion of the entire cost ($4000). My issue right now is mainly with the labor costs of $2500 to install the system and remove the old tank heater from the kitchen, which seemed high, although significantly more reasonable than the first estimate I received. Since I have so far received two high, but wildly varied estimates, I am not giving up yet! I'm going to get a couple more estimates to make sure I'm comparing apples to apples.

OK, this is all hugely fascinating. The seller just signed off on the contract and now I'm in full what-to-fix-before-all-my-stuff-is-in mode.

I'm wondering how dramatically the cost estimates vary around the country; I live in N.C. and I'm wondering whether our usually-lower-than-average estimates will pan out, per usual, or if there will be some kind of cost penalty for making my plumber figure out the newfangled tech.

On the other hand, the new house is just over 900 sq. feet, so at least I can be sure that one unit will do the job.

Good for you. I know that there has to be a decent estimate out there. The unit itself is about 1000-1200 and you get a big rebate on it. The task of removing should not be a big deal at all ...it took them about 15 min. The running of the gas line was not much since it was right by the meter. So the electric is the only thing and I helped run the line for that and stapled the clamps to the joists since my electrician used me as his helper most days. I still think 4K is crazy if you figure $65 an hr for most of these pros. I hope this works out for you. c

Just wanted to give an update on the tankless water heater estimates. I now have 4 estimates.

First estimate was for 2 tankless Rinnai water heaters, which would require furring out the exterior wall and recessing them. 3 control panels (MB, laundry, kitchen) $15,000. Yowsa. No thanks.

Second estimate was for a Noritz 751 model including 1/2'' L copper pipe to tie it into the furthest bathroom. Removal of old water heater and plumbing/gas/venting. $3750. Discounted annual maintenance service offered. Did not include cost for electrical. Did not include water filtration system. This place sells both Noritz and Rinnai, but prefers Noritz because he says they stand by their warranties better and he has better luck getting warranty service and parts from Noritz over Rinnai.

Third estimate was for a Noritz 751 model including recirculating pump and L copper pipe to tie into furthest bathroom. Removal of old water heater and plumbing/gas/venting from kitchen. Did not include cost for electrical, permits, or water filtration system. $4,650.

Fourth estimate was for a Noritz 751 model + a small pre-system water filtration system. Did not include cost for a recirculating pump. $3,421 minus a $200 rebate from Noritz and a $200 matching rebate from the installer/seller ($3,021 total). Said we didn't need a recirculating pump unless we demanded instantaneous hot water at the furthest bathroom. For the next larger size, the 931 model, cost would be $3821 minus the two rebates, but still no recirculating pump. This guy sells both Noritz and Rinnai, but recommended Noritz for exterior application and Rinnai for interior application. He said that Noritz and Rinnai warranties are void without either soft water or some sort of pre-system filtration.

So that's the skinny for tankless in the OC. Having some difficulty evaluating which route to go since each estimate provided different things, and I got different stories about why I needed this or that from each place.

Hmmmm still seem really high to me . I don't have anything in my Noritz warranty that says that and I read it several times. It tells how to clean it if you have hard water to prevent deposit buildup but no " you have to have" in there. I guess your 4th estimate makes the most sense to me w/ rebates and I really don't think you need the recirc, but also don't need the filter....do you have really special water where you are ??? And you do only need the 1 control also. So I guess #4 or nada. How many GPM is the 751? c

I looked at the specs on the Noritz website. There are two numbers listed for gallons per minute: max hot water capacity is listed at 7.5 gallons per minute at a 45 degree rise, and a gallons per minute range at 0.5 (minimum flow rate) to 9.8 GPM (not sure how this relates to the 7.5 gpm figure).

The owner's manual pdf states on p. 6 in bold letters (that's a legal thing meaning, YOU SHOULD HAVE READ THIS, DON'T COME CRYIN' TO US):

"Treat hard, acidic or otherwise impure supply water with approved methods to ensure full warranty coverage."

and

"Problems resulting from scale formation are not covered by the warranty."

So it sounds like #4 knows most about what he's doing and has the most "reasonable" price, but the high labor cost may be due to locale. I swear everything here costs $$$ even if there is no reason for the difference. Think I'll next look into whether tankless water heaters will get me any sort of government energy rebates to make up the difference in cost.

For any other OCers out there thinking of going tankless -- let me know; we can compare notes on the estimates. :-)

Just an update -- we decided to go with the #4 estimate guy, and our tankless water heater is being installed as I write! :-) On the bright side, the estimate was somewhat better than I expected because unlike the second and third guys (both strictly plumbers), the company we went with specializes in tankless water heater installations, so their installation includes everything: gas line, plumbing and electrical, removal of old water heater and cap off of old gas, plumbing, vent in the kitchen, as well as the pre-system filtration unit. And the double rebates gives a better rebate than the one that the government was giving last year (all government rebates on tankless water heaters in our area have expired).

I'll post a review and pictures this weekend after I get to try it out, but so far, very exciting. No more water heater in my kitchen! Yay! Thanks everyone for all the advice, experience, etc., and special thanks to les for starting this thread.

YAY...sara. I am so glad. and you are right...I must be blind !! We luckily have no hard or acidic water here. When we had the internal filter checked it was completely clean. I will look forward to your pics and assessment. C.

So the tankless water heater company put the temp control panel on the outside of the house next to the heater. I thought it was supposed to go inside somewhere?

It should be indoors. You don't want to go outside to change the temp. Call 'em!

YES it is supposed to be inside. I have mine in the laundry area next to the washer. I don't change it often but I sure wouldn't go outside !! They haven't read the ads for these...it even says to get more than one controller if you like to be able to change at point of use. Go call. c

ARGH! I thought so. This is what happens when I leave DH to deal with these things. Contractor and DH take the easy way out. ARGH.

I mentioned to DH that it was supposed to be inside; his reaction was, why? We never changed the temperature on the old one, why would we now? He doesn't want me to call. Is there a reason I would need to change the temp on the water heater?

Well I bump it up to 120 and leave it as long as we are having cold weather. In the summer I keep it at 105 and when I wash whites I put it to 120 and also 120 when I run the dishwasher. I have a Bosch with the internal heater but they suggest 120 as a starting point to save time and energy.

The reasoning for the lower temp vor bathing is that you are wasting energy by heating water hotter than you need and adding cold....like you do with the regular old fashioned water heater. So I guess you need to think about lifestyle. In winter no change and in summer some runnin' to and fro....not horrible but perhaps a PITA ..you decide. c

Thanks, caroline. That helps. We all like REALLY hot showers and baths around here all year long, so I can't see us changing the temp. Even DD threw a small tantrum tonight because she wanted the bath water hotter!

I had to finally cave in and get a water softner since my area has one of the hardess water in the USA I am told and all my toilets and sinks were being ruined with having replacements being done prematurely as a result. I finally added a house water filter to filter the water after it is softened. I also have a water filter on my refrigerator. I hope this helps.

I know I may need a new heating/air conditioner central system soon as well as a new water heater so this discussion I have been following but do not know much about yet. Thanks everyone for sharing. Please Sarschlos_remodeler update us on how you like your unit when a little more time passes.

sara then I would not bother to move the controller and this way DH and DD will all be happy. We have open "wet" room bathrooms so in the winter , even with wall heaters on. the spaces are cooler. So we like hot showers. But in the spring/summer I like tepid. No hot for me and DH says the same. Since we only have ourselves to please we turn it way back. Glad you have it resolved ! c

"and special thanks to les for starting this thread."

You're welcome, Sarschlos. It was a 'tankless' job, but somebody had to do it! LOL

I learned a lot, and have passed the information on to my in-laws. Thanks to everyone who responded here.

Groan, les! lol.

Update: Tankless is working just perfectly so far. I'm very happy with it. Takes less time to heat up in the farthest bathroom than it did with the old water heater. We decided not to bother changing the location of the control panel since we're unlikely to change the temp.

Great Sara...may you have lots of hot showers. One selling point, that a friend told me, was that I could have the entire NFL come shower and never run out of hot water....uh..well...who is going to clean the bathroom after ?? LOL. I'm not sure that is what she meant ! c