T(h)ankless Water Heaters

[Aaron Miller]

A good article to pass along to clients:
Are Tankless Water Heaters a Waste of Money? | GreenBuildingAdvisor.com (http://www.greenbuildingadvisor.com/blogs/dept/musings/are-tankless-water-heaters-waste-money?utm_source=email&utm_medium=eletter&utm_term=energy-efficiency&utm_content=20120411-tankless-water-heaters&utm_campaign=green-building-advisor-eletter)

[Nick Ostrowski]

Great info Aaron. I see very few of these units (maybe one every year or two) but I do get questions about them. Looks like the cost savings just are not there to justify the expense.

Does anybody have an idea of what the average life expectancy is of these units?

[wayne soper]

On average, if serviced, cleaned and pampered , I believe they last to just a few years prior to when they would have paid for themselves, 20 yrs

Just like everything else, why would they build something that would actually last, when they can build crap and get us to keep buying them.

Solar, same thing

I wonder how much greenhouse gas is burned in the making of all that money?

[Bob Harper]

I like the (h) pun. I'm not a big fan of these units for a number of reasons. First, they are expensive. You can buy several CAT I gas water heaters for the price of just the equipment.

They are more expensive and complicated to install. Special fittings, valves, etc. plus the wiring, etc.

They require a LOT of gas when firing. These things are notorious for dropping out other combustion appliances, which has often necessitated the installation of a dedicated 2 psi gas supply to them (read: expensive and more to go wrong). Often the meter itself must be upsized.

Nobody seems to be able to install the venting properly. I've found most of these units improperly vented. Apparently, most plumbers cannot read instruction manuals, don't want to be bothered with instructions or "know enough" on their own they don't need no stinkin' instructions since they've "done a million of them". Now, that's a scary thought!

They require expensive annual maintenance. Most homeowners who pay for the 'annual' maintenance get sticker shock then try to make that their once in a lifetime maintenance. Meanwhile, the scale decreases the efficiency thus minimizing any gains over traditional water heaters.

They often cannot meet the demands placed upon them. Sizing and lifesyle are important in the decision tree.

Some have funky parts that are not typically stocked locally.

They are a poor choice for hard water.

Other than that, every home ought to have one if we're to fend off global warming and save the polar bears.....

[John Kogel]

Not long ago, I saw a house with both a tankless and a storage tank water heater. The owners had turned the gas off to the tankless. :D

Would 2 small storage tank heaters be better than one large one? I think so.
The cost is a little high, close to double for 2 tanks, but one could feed warm water to the other, and could be turned up when company arrives.

[Bob Spermo]

I installed and use an on-demand tankless gas water heater and I love it! It is in a laundry room on the exterior wall so the venting was easily installed. I routinely run 2 showers and a washing machine at the same time and there is plenty of hot water. I have used it for 5 years with no problems. My cost was less than $1000 and my gas bill to heat the water is $2 - $3 a month! It produces 6.5 gals of hot water a minute.

[John Wood]

I have installed a number of these units. In my experience there is really only 3 situations where I recommend them.

First - if someone uses a spa tub where it takes large amounts of water to fill them. The tankless are unlimited and some of these spa tubs use 60 to 80 gallons

Second - if people travel or there are intervals where people do not use their hot water. A tankless will sit dormant

Last - if space is an issue!

Some of the problems I often run into, are that unless it is new construction most gas service is too small; the distance from the meter is too far, or the supply to the unit is undersized.

Additionally every time you turn the faucet (or demand) off, the unit turns off and resets. When the demand turns back on, it takes a couple seconds for the unit to fire up, recalculate itself and produce hot water. The result is a Morse code of hot and cold dashes of water in the hot water line. People saving water and turn off a shower to lather up find a nice surprise.

[Garry Blankenship]

Great article and so is your word play thread title. Ultimately a tankless heater is a, ( hopefully ), conscious donation to the green cause. Two items I did not notice is the instant "on demand" electrical load required by electric tankless heaters. Most services can handle it, but not all. Upgrading an electrical service to accommodate a tankless water heater would move the payback out another century or so. Another often overlooked cost factor for conventional electric water heaters is how replacing the sacrificial anode in them can substantially increase their life span, probably double it. Easy enough to do, but talk is cheap. Good fodder to explain to clients, however.

[Ron Keeney]

Keep in mind that there are some valid uses (locations) for tankless heaters, either gas or electric, that should not be overlooked. Perhaps its just a question of looking at them as replacements for the main hot water heater or as "point-of-use" water heaters. Examples:
1) When a "Powder Room" is remotely located from most other plumbing and the hot water only gets used for quick hand washing.... running all the cold water out of the hot water line for 10-15 seconds just to get 10-15 seconds of warm water is quite a waste of water, and afterward that hot water just sits in the pipe in cools off again;
2) When a bathroom is not used often, such as the one in a Guest Room suite, there's an inefficiency in supplying hot water to it all the time;
3) As part of a "hot water house humidification system": These require just a trickle of hot water down across a metal mesh matte thru which a fan then blows humidified air out into the house. But keeping hot water in that pipe up from the normal water heater for just that little trickle (particularly in demand on a cold winter night) is expensive. (Yet the system works well because it's relatively self-cleaning by washing the typical calcium build-up down the drain.)
4) When an element of the bathroom is not used much (we have a shower stall in a remote Powder Room) it makes more sense (cents?....) to use a Point-of-Use water heater to supplement that hot water rather than keep enough hot water in a tank awaiting the shower use.

For commercial spaces, we have been in the habit of installing the smallest available hot water tank (10-20 gallons), knowing that they only get used for hand washing in a commercial / retail rest room. But in just the last couple of years, those small tanks are becoming very scarce and difficult to even find -- being replaced by electric in-line "point-of-use" water heaters.

[John Wood]

I think the thread is got a little misdirected. The original posts were to the gas tankless (whole house) water heaters, but the little insta hots that go under sinks are a whole different subject.

[Raymond Wand]

1.If you have hard water a water softener is a good idea with condensing units.

2.There will be a delay in hot water regardless what type of unit one has. Why would you expect instant hot water. There are work arounds if you want instant hot water.

3. In Europe these condensing units are very common, and I don't hear complaints.

4. Yes they are expensive. Recently I had a quote for a Navien unit and it came in at $4,800.

5. Sizing is important - incoming water line temp, number of persons in house, number of bathrooms.

6. There is no standby loss and not keeping 40-60 gallons hot.

-:- Navien America -:- (http://www.navienamerica.com/professionals/unitselection.aspx?skin=unitselection)

Water Heater Efficiency :: Hybrid Options (http://www.healthyheating.com/water-heater-efficiency.htm)

[Garry Sorrells]

I don't know if referencing Europe is in its favor.
"...3. In Europe these condensing units are very common, and I don't hear complaints...."

Europeans have vast differences in expectations that North Americans.

30 years ago I had a European ask what was the purpose of screens in the windows.
Did not understand until I did some research.

Europe accept $6 to $10/gal gas also....

[Raymond Wand]

Europeans also like baths more than they do showers.

They have dishwashers, laundry and several occupants, so whats the difference or what is different about their expectations?

[Ron Keeney]

Obviously, once one gets past the technicalities like power source and potential venting, the difference is simply LOCATION (close proximity to the plumbing fixture means less wasted water (cold) while getting to the hot water.....) and SIZE (you can't put a conventional 40-gal hot water heater tank under a bathroom sink...). One can then add QUANTITY (or amount of use and therefore convenience and cost savings due to not having to heat the water that gets left in the pipe to cool off after the fixture use).
But like any choice of a construction material, the list of considerations after that becomes typical and extensive: initial cost of the unit, initial cost of the installation, the cost per gallon to heat the water, the cost of maintenance (annual draining, etc.), the expected lifespan -- all shaded by the local energy costs, the quality of the water.... even local government "taxes".
Everything COULD to be calculated in for MOST such building materials, but I doubt it's worth getting past the first two or three major elements.

[Garry Sorrells]

Ron,
So, what is your labor - material differences on installing a 40 gal tank as opposed to a whole house thankless heater?

[Raymond Wand]

Recently rec'd a quote on installation for a Navien condensing unit. Including installation and taxes it was $4700!

[Garry Sorrells]

Recently rec'd a quote on installation for a Navien condensing unit. Including installation and taxes it was $4700!

Did you have any discussions on cost effectiveness with owners?

[Raymond Wand]

No I didn't, but that was not a consideration for the homeowner.

[Rod Butler]

No I didn't, but that was not a consideration for the homeowner.

I think that sounds typical and in reality I am all for wealthy people installing tankless heaters, solar collectors, PV panels, and driving electric cars. Makes the mfr's work on the technology to get it to the point where I might be able to afford it.

[Ross Neag]

Rod, you stole my line! It definitely helps drive hot water technology in the right direction. Ironically, I own a Noritz NO-69 and both love and hate it. The master tub can get hot water in about 20 secs but also runs an enormous amount of water to do it. Less than 5 feet away at the master lav I have to wait 1:45 for hot water after standby. That is unacceptable. The Mrs. takes a lot of baths, now its a plus again.

It's not the perfect appliance but has its use. You can't denounce those who have them anymore than someone choosing to drive a Mercedes when a Camry will do the same job (i.e. moving you). I really like the sealed combustion 50 gals and electric heat pump units that have come out in the last few years.

Another thing I hate is listening to all of the cycling during a warm or hot laundry load. All of those start up cycles will eventually take its toll and I think I will see less than 12-15 yrs on this.

FYI- just two people in our home, Mr & Mrs

[Jim Luttrall]

Rod, you stole my line! It definitely helps drive hot water technology in the right direction. Ironically, I own a Noritz NO-69 and both love and hate it. The master tub can get hot water in about 20 secs but also runs an enormous amount of water to do it. Less than 5 feet away at the master lav I have to wait 1:45 for hot water after standby. That is unacceptable. The Mrs. takes a lot of baths, now its a plus again.

It's not the perfect appliance but has its use. You can't denounce those who have them anymore than someone choosing to drive a Mercedes when a Camry will do the same job (i.e. moving you). I really like the sealed combustion 50 gals and electric heat pump units that have come out in the last few years.

Another thing I hate is listening to all of the cycling during a warm or hot laundry load. All of those start up cycles will eventually take its toll and I think I will see less than 12-15 yrs on this.

FYI- just two people in our home, Mr & Mrs

Now throw the "hybrid" water heaters in the mix for the best of both worlds. (or the worst... since I have not lived with one!)

[tom daley]

Just a mention of something i know two cents about:FWIW,

Condensing Boilers, as they are known in the UK & Ireland have been mandatory installations for the last few years. They have not so far been a success - for many of the reasons cited above. Essentially, they are complicated, expensive and have introduced new operating difficulties that were not thought thro before marketing.

My thoughts are that by the time they've sorted things out, a new generation of water heaters will have arrived.

Many installers are leaning towards a US type of tanked w/h, with more bells and whistles.

Boilers over there, of course, split the hot supplies into seperate domestic use, and hydro-heating use.

[Bob Harper]

Think about it for a minute--you install a tankless WH to save the planet then run huge amounts of hot water to take a bath, spa, hot tub, etc. instead of a frugal shower?

You spend over $4K on something that will take 10 yrs to payback when that same $4K spent on weatherizing the attic would payback in probably 3-4 yrs AND make the house easier to keep comfortable year round?

Seems a little oxymoronic to me. Kinda' like installing a condensing boiler to save money on a snow melt system for the driveway or swimming pool heaters. Talk about waste!

[Ted Menelly]

Think about it for a minute--you install a tankless WH to save the planet then run huge amounts of hot water to take a bath, spa, hot tub, etc. instead of a frugal shower?

You spend over $4K on something that will take 10 yrs to payback when that same $4K spent on weatherizing the attic would payback in probably 3-4 yrs AND make the house easier to keep comfortable year round?

Seems a little oxymoronic to me. Kinda' like installing a condensing boiler to save money on a snow melt system for the driveway or swimming pool heaters. Talk about waste!


That was the most direct and best addition of intelligence to the entire thread.

Many items put forth to save the world kill it in other ways. Cost more to do so. Manufacturers take advantage of the forgone conclusion everyone today is putting forth "Its expensive butttttttt"

This is why Solar will more than likely never take off. The massive amount of engineers and presidents and vice presidents and stock holders all banking on huge payouts tripple the cost of what solar could and should relally be.

This day and age is nothing more than mass marketing and so many believe they are the Godsends of the world and should get paid everything for it.

Oh well. I might as well throw this in

JP Morgan???????? 2 billion gone? Still selling something that really has no dollar value and the heads making fortunes doing it.

Just wehere could it have gone :confused:

Sorry. A little drift but kind of on track with the thread.

[Bob Harper]

I can't wait to hear from all those people who carpeted their roofs with solar panels that were heavily subsidized then will be left holding the bag when they need a new roof and have to actually pay out of pocket to uninstall then reinstall those panels that eventually will require maintenance/ replacement.

The most cost effective solar is passive but even that comes with an increased cost over conventional methods. Now we have the Green Building weenies advocating 100% glass wall construction. Peekaboo! No end to these green weenies...

Thx Ted

[Aaron Miller]

Green Building weenies

Is that a technical term from the BBQ section?

[Rod Butler]

I disagree with several positions posted above. Those that I disagree with may respond as desired, please keep it civil.

Condensing boilers; They do work and are very efficient and from my experience very reliable and simple to operate. I personally have installed four condensing boilers and have just had two condensing boilers installed in our new office building. They are working very well. The only disadvantage that I see is the individual unit capacity limitation at just under 400,000 BTUh's.

If you are in the position to be able to afford a snow melt system or heat a swimming pool, you damn sure should be using the highest efficiency equipment on the market. And even though I may be envious or even if I think it wasteful, I appreciate that some of those people are using the high efficiency or solar equipment.

People that are going to take many baths in their large tubs or long showers are going to do it regardless of the type of water heater. it would make better dollar sense to reduce consumption at the source but this is a free country and people will exercise that right based on their personal choice. It does make sense that if you are going to continue consuming large quantities that you do so in the most energy efficient way possible. Tank-less heaters make sense for some people.

Solar will take off, but not until it becomes economically feasible to do so. Fossil fuel in my opinion is a finite resource, maybe not in any of our lifetimes but it is finite. The only infinite resource is solar power and as energy costs continue to escalate it will continue to make more sense.

For those that have installed it so far and may have installed it incorrectly so that it may necessitate removal for construction repairs, I feel for you. Designs improve as a result of past mistakes but that should not discourage us from trying new ideas.

The bottom line as I have stated before is that if you can afford the use of high energy efficient cars, appliances, homes, even snow-melt systems, . . . please do so. We will all benefit in the long run with reduced prices as a result of mass production.

My brother has a home on the Big Island and in Southern Utah. In both places he lives off of the grid using solar collectors and salvaged building materials. I choose to live a different lifestyle the he, but I applaud him for doing it his way and reducing his footprint for the good of many.

At the end of the day we can only control what we consume in our own way and hope that others do their part as well.

And that's all I have to say about that. :)