Tankless water heater. Any good?

[Swftonyc.com]

I'm also considering replacing this 50G water heater with a tankless one. It looks they save money in the long run, especially for me who just need hot water for showers. I've done some research online and found mixed review about those tankless water heaters. Have anyone tried them? Are they any good?

 

[Cacher_Chick]

The initial cost is high and they are not nearly as reliable as a tank unit. Depending on the gas service provided, it often needs to be up-sized to supply adequate fuel to the unit. They are good if you need a continuous supply of hot water. They are an option if you have very little space for placement of a water heater. For the average single family residence, a tank is more economical and will require less maintenance.

 

[Sponsor]

 

[Jadnashua]

There are lots of threads on tankless systems and there's at least one article in the tutorial section about them.

The biggest things to know are that they have a minimum flow rate before they turn on. That may mean no warm water to wash your hands at the sink depending on the unit and how it is setup. They are also very dependent on the incoming water temperature. Being in NYS, your incoming winter water temperatures can approach freezing...most of the specs on the things talk about 50-55 degree incoming water...trying to heat that an extra 20-25 degrees as it flies past the heat exchanger often means it doesn't get as hot as you may want. Summertime use usually isn't an issue unless you have a deep, cold well.

 

[Master Plumber Mark]

if you just want hot water and not have to worry about bi-annual maintenance
I suggest you just get yourself a tank type heater, have it installed and not worry about
it for about 10+ years... You can flush out the bottom with a garden hose a few times a year
for free.... very simple and very easy......


Now, if you are into tweaking and maintaining a system because you like to mess
with mechanical sort of things.. then tankless heaters are right up your alley...
You will get to learn about "flow rates" through the unit and how only one person
can take a shower or use a faucet at one time..... This will be your first surprise

You will also get to learn how to de-lime your tankless heater after you have a
plumber come out and hand you a $300 bill for doing this service for you.....
So bi-annual de-limeing of the heat exchanger is something you will look forward to
learning how to do yourself. Surprise , surprise

Also if the unit goes down, you will get to learn how to trouble-shoot the system because there is
no competent service man within 50 miles of you......or he is booked for 2 weeks...... Surprise surprise

Am I making any sense here ??

 

[Dana]

If your space heating is being provided by a hydronic boiler (rather than a hot air furnace or something else) you will get better and more reliable hot water service & value out of an indirect fired water heater operating as a "priority zone" off the boiler than with a tankless, and you won't have to upgrade the gas service or the gas distribution plumbing inside the house, which can be expensive cost-adders when "upgrading" to a tankless.

When correctly installed, the standby loss of the indirect water heater is much lower than a standalone 50 gallon tank.

If your space heating boiler is a non-modulating type you can achieve even higher combined net efficiency by installing both the indirect water heater and retrofitting indirect-aware heat purging boiler control such as an Intellicon HW+ or similar. This is even more true if the boiler is grossly oversized for the actual space heating load (true of MOST of the boilers found in homes in the northeast.)

 

[Master Plumber Mark]

If your space heating is being provided by a hydronic boiler (rather than a hot air furnace or something else) you will get better and more reliable hot water service & value out of an indirect fired water heater operating as a "priority zone" off the boiler than with a tankless, and you won't have to upgrade the gas service or the gas distribution plumbing inside the house, which can be expensive cost-adders when "upgrading" to a tankless.

When correctly installed, the standby loss of the indirect water heater is much lower than a standalone 50 gallon tank.

If your space heating boiler is a non-modulating type you can achieve even higher combined net efficiency by installing both the indirect water heater and retrofitting indirect-aware heat purging boiler control such as an Intellicon HW+ or similar. This is even more true if the boiler is grossly oversized for the actual space heating load (true of MOST of the boilers found in homes in the northeast.)

We dont see a lot of these any more in the mid west .....especially the oil burning boilers
they have gone the way of the dinosaur...... I am not a fan of them , but in their day they
worked pretty well...... Some I have seen in the past you had to keep the boiler running all summer
long to heat the water... where others were only a back up and worked only in the winter months....

I dont really know how efficient this actually is and what this has to do with this thread...

 

[Jadnashua]

Many places in the NE do not, or didn't have NG available, so your heating choices were, electric, propane, or oil. There were a lot of oil burning boilers in the area, and some still don't have NG.

A modern cold start boiler works fine for use with an indirect, even in the summer, since it isn't damaged by cold starts. Older designs often needed to run all summer, or you had an oil-fired HW tank, or an electric WH to make things easier. Radiant heat is much nicer than scorched air, but can be more expensive if you need ducts for a/c that are only used part of the year. But, they can be optimized for cooling rather than being a compromise for one or the other.

 

[Dana]

We dont see a lot of these any more in the mid west .....especially the oil burning boilers
they have gone the way of the dinosaur...... I am not a fan of them , but in their day they
worked pretty well...... Some I have seen in the past you had to keep the boiler running all summer
long to heat the water... where others were only a back up and worked only in the winter months....

I dont really know how efficient this actually is and what this has to do with this thread...

OK, I'll accept that you really don't know, so lemme 'splain ya:

Since he's talking about a tankless, it means he's probably either on the gas grid, or maybe he has propane. It's unlikely (but not impossible) that he's replacing a 50 gallon oil fired water heater, but it could be electric.

Hydronic heating (all fuels) is still pretty standard in swftonc.com's Hudson Valley location, even for new construction. But it is nearly universal in pre-1990 construction. It's a reasonable expectation, since he's not " ...in the mid west...".

The hot-water only efficiency of indirect HW heating + boiler is comparable to that of a non-condensing tankless even when the boilers are right sized, but in cases where it's more than 2x oversized (more common than not) the increased duty cycle has an even higher benefits on fuel use. This has been studied for decades at the Broohaven National Laboratory. Those data have been the basis for providing the same sort of rebate subsidies in NY / NE state efficiency programs as tankless water heaters.

An indirect does not have the same gallons per minute limitations of a tankless, and effectively zero pressure drop to create problems with mixers & anti-scald valves. If there is a pre-existing hydronic boiler the installation cost will be LOWER than a new tankless, and it's a better solution in terms of hot water delivery.

In short, it's even odds or better that the place is heated with a boiler, and if the place is heated with a boiler the combined efficiency improvement will be comparable to a tankless, upfront costs are less, and the hot water delivery will be better.

And that's what it has to do with this thread.

 

[Master Plumber Mark]

I'm also considering replacing this 50G water heater with a tankless one. It looks they save money in the long run, especially for me who just need hot water for showers. I've done some research online and found mixed review about those tankless water heaters. Have anyone tried them? Are they any good?


It looks like a simple 50 gallon gas heater the guy is talking about
and you go into a dissertation on how a indirect boiler would work
for him.... if he has a boiler in the first place.........

I suppose he could also have propane or even solar too.....
why dont you give us all a lecture on how the solar would work out
if that is what he has in his home.... There might be even odds on that too.......

 

[Jadnashua]

A tankless, IMHO, is rarely the least expensive or best solution. SOMe situations, they work great, some, they do not.

NOt counting installation costs, in order of operating costs, things go sort of like this:
- solar heated tank
- indirect tank
- NG WH
- Might be a tossup between propane or electric WH
- oil WH
- tankless

IMHO, throw in initial costs, limitations, maintenance required, and tankless often still sits at the bottom. If you don't already have a boiler, disregard the indirect.

The allure of endless hot water comes at a price, and if not carefully sized for the intended job, can often disappoint. ANd, if you don't do the periodic maintenance (the harder your water, the more often it is required), your performance can quickly erode. Then, try getting a repair part in a timely fashion...may not happen, as they aren't composed of mostly universal, interchangeable parts like typical tanks. Finding a good tech can be a problem, too. You may be lucky and have a competent one nearby. Not everyone can fix a tankless system, at least efficiently.

 

[Master Plumber Mark]

A tankless, IMHO, is rarely the least expensive or best solution. SOMe situations, they work great, some, they do not.

NOt counting installation costs, in order of operating costs, things go sort of like this:
- solar heated tank
- indirect tank
- NG WH
- Might be a tossup between propane or electric WH
- oil WH
- tankless

IMHO, throw in initial costs, limitations, maintenance required, and tankless often still sits at the bottom. If you don't already have a boiler, disregard the indirect.

The allure of endless hot water comes at a price, and if not carefully sized for the intended job, can often disappoint. ANd, if you don't do the periodic maintenance (the harder your water, the more often it is required), your performance can quickly erode. Then, try getting a repair part in a timely fashion...may not happen, as they aren't composed of mostly universal, interchangeable parts like typical tanks. Finding a good tech can be a problem, too. You may be lucky and have a competent one nearby. Not everyone can fix a tankless system, at least efficiently.

\


Well stated........


now please close this thread before Dana begs to differ with you......

 

[Dana]

A four sentence description of the indirect option along with a picture is hardly a dissertation (at least not where I went to school. YMMV)

Having to explain to some random midwesterner why it's probably relevant to someone in Hudson valley clearly needed more words.

I'm also considering replacing this 50G water heater with a tankless one. It looks they save money in the long run, especially for me who just need hot water for showers. I've done some research online and found mixed review about those tankless water heaters. Have anyone tried them? Are they any good?


It looks like a simple 50 gallon gas heater the guy is talking about
and you go into a dissertation on how a indirect boiler would work
for him.... if he has a boiler in the first place.........

I suppose he could also have propane or even solar too.....
why dont you give us all a lecture on how the solar would work out
if that is what he has in his home.... There might be even odds on that too.......

A four sentence description of the indirect option along with a picture is hardly a dissertation (at least not where I went to school. YMMV)

Having to explain to some random midwesterner why it's probably relevant to someone in Hudson valley clearly needs more words.

 

[Master Plumber Mark]

Well chickaree-bow-howdy......
I did not realize what a mid-west hayseed I was till you
explained it all to me Dana...

The reason I dont know anything about tankless hot water heaters is because
us mid-westerners only take baths on Saturday nights and dont need an endless supply of hot water....
you northern folks do need to bathe more often..
.

Yee-haw......

 

[Dana]

I didn't realize midwesterners in general were considered hayseeds, but it's been decades since I lived in Indiana ( then later, Illinois.) I guess I'll have to take Mark's word for it.

In upstate NY they don't bother bathing in the winter- that's a springtime weekend activity, but that's another story... ;-)

The fact that hydronic boilers, and in particular oil boilers aren't very common in the midwest particularly relevant to the discussion either, given that the original poster is in NY, eh? I figured swftonc.com is probably on the gas grid based how the original post was worded, with at least 50/50 odds that the place is heated by a boiler based on the location. Could be wrong on both counts, but four sentences and a picture isn't a huge distraction (or is it?)

I don't know what the prevalence of hydronic heating systems in the midwest has to do with this thread...

Were I responding to someone in IL or KS the indirect water heater zone an existing boiler solution would have been a long shot, but in NY it's pretty likely, so I ran it up the flagpole, since it's a better solution by most measures. By begging the question with, "I dont really know how efficient this actually is and what this has to do with this thread..." it's a bit odd for Mark somehow be offended by the answer, since there really is an answer to both the efficiency and relevance question.

Just don't ask me what time it is, that could be a really long story...

 

[Master Plumber Mark]

you just go on and on...... reading your post is like beating a dead horse...
I don't think the guy is even gonna come back here and
tell you what kind of heater he is actually talking about
so why don't you let it go......

I gots me some vittles to eat then gonna go on a hay ride
gonna be a full moon night so that's what we do here in the mid
west......

he haw...