My Tankless Experiment

[master plumber mark]

Another beautiful Sunday Morning Indiana week #2
Temps are now starting to drop in the area

My 75 gallon Brad white gas how water heater
has now consumed a total of 1235 cub feet

looks to be averageing about 618 cub feet per week..

still need to look up my cost......per therm.

[GrumpyPlumber]

Mark, I'd figured you connected the tankless by now.
A difference of temperature as little as 10 degree's makes a difference in btu consumption.

[master plumber mark]

At this point of this experiment I am lucky to
have gotten this much done...


Thought I would give the 75 gallon a month or two
of readings....


I realize that this means that the Tankless will be comming
on line in the winter and the readings would
be at their absolute worst...


.


Or I can wait till around x mas and do the change out...


Ideally it would have been more fair to have done
this during the summer...

but we have winters here and the tankelss will
still have to perform every year through that season...

gas consumption and performance are both on my mind here

the incomming water temp is now 69 degrees....e




I am hopeing to get a Large Takagi tankless in a few weeks


to be perfectly fair they should be both running at the same time..
.through the exact same season

but I am doing what I can with what I got...


if you have a spare takegi that will handle 3 bathrooms
for dirt cheap or free......send it my way

[master plumber mark]

The temp of the incoming water is holding at 69 degrees

We have had company come into town this week since friday....the big sister in law is
in town staying with us...

takes a lot af water to hose her down........

presently the amount of CUBIC FEET used by the 75 gal gas is at 2065. cub feet


this messes up my esperiment a little but I suppose
I can use the figures for the first two weeks an be ok

[master plumber mark]

week 4...Temp is now down to 67 deg..

had company this week for a funeral...

the gas meter is now sitting at 2800 cu ft...

[master plumber mark]

the meter is now at 3500 cu ft

the water temp is now at 63 degrees...

I am sort of interested in seeing how much gas
the heater will use when the water temp crashes to
about 45 degrees this winter..

[master plumber mark]

temp is now at 60 degrees...

cubic feet used to date 4300..

[master plumber mark]

heater has now used 5030 cubic feett

water temp is now at 60 degrees....

I still need to see what a cu foot is costing me


looks to be averageing about 700 cu ft per week......

[Bob NH]

heater has now used 5030 cubic feet.

water temp is now at 60 degrees....

I still need to see what a cu foot is costing me


looks to be averageing about 700 cu ft per week......

Look at your last two gas bills. Assume that 100 cubic ft is one THERM. It is probably costing you about 1.5 cents per cubic ft.

[master plumber mark]

I was gonna get around to calling the gas company to
nail that down tomorrow...

I will be spending the day at home with a sick kid...
so its time to catch up on my paper work


at 1.5 cents which you claim it shoud be per cubic
foot that only works out to about 75 bucks for 7 weeks???

5030 cu feet x .015 = 75.45

or about 10 bucks per week??

[jadnashua]

Now, with the water meter, how many gallons of water were heated? You can then figure out approximately how much was used to heat it the first time, then how much was standby losses. You have the average input temp so you know the temp rise the heater is trying to provide.

[master plumber mark]

I think That would really be cutting some fine hairs....

That would involve putting another meter on the
heater to measue water usage ...

I am only looking at the average usage for a family of 4....
a ballpark average is good enough
I am not going to get suckered
into turning this into a bigger project than it already is

I dont think its necessary to figure out exactly how much
energy it took to heat up 100 gallons of water...

Especially when at this point it looks to be doing about
only around a measely 10 bucks a week anyway....


this is all very boring right now...in Week #8 but they
seem to be passing very fast.... .


The big hurdle is still ahead some day with the tankless
unit ......probably next spring...

of course I am still in the "procurement phase."

I am still looking for one of the owners of a supply house
around here to donate a scratch and dent one to me.......
that will do 3 bathrooms...

[GrumpyPlumber]

I'll guestimate,
At 22-24% higher efficiency and the standby heat loss on a 75 gal, You'd save about $2.50-$3.00 a week.
Approximately $140.00 a year.

[master plumber mark]

I'll guestimate,
At 22-24% higher efficiency and the standby heat loss on a 75 gal, You'd save about $2.50-$3.00 a week.
Approximately $140.00 a year.

So Grumpy.....you have not been around for a while...
did you get back from a vacation to Europe or some place exotic?


I found another site that claims a tankless will save as much as 23 dollars per month to heat the water....

it dont seem realistic to install the tankless if all you
are going to save is a so small....

here is the article I found from the Plum biz newsletter I get

Are they really cost effective?
Last week I started prying open a can of worms concerning the cost savings of tankless versus storage type water heaters. It's been over twenty years since I had my first practical lesson in the benefits of both. With the help of the engineers at PVI water heaters (I live less than two miles from their HQ) I wrote the specs for a municipal maintenance facility. The facility included crew showers which, if I remember correctly, would accommodate 8 mechanics at once. In theory, they would likely all be hitting the showers at the quitting time so we needed to provide enough hot water for all of them at once. To handle the task, we installed a 250 gallon tank type heater which only had about 100,000 btuh or so for a burner (I could be off a bit on the burner size). At first, I thought their engineers were just trying to spec a big tank but then I realized how much money we saved on the project by specifying this monster. For all I know, it could have been the key to winning the job.
Installation costs were shaved in several ways: The flue was considerably smaller than one which was necessary for a quicker recovery unit. This was important since the roof was about 20 feet overhead. Then, there was a considerable savings on gas piping. If we had run piping for a half million btuh burner we would have been into welded pipe sizes, instead of being able to stick with screw pipe. Let's not forget that by being well under the 200,000 btuh boiler threshold we didn't have to deal with an ASME rated tank.
The tankless market is asking us to reverse these infrastructure savings. Although there are plenty of instances where a tankless model makes good sense (I have no plans to remove them from my price book system) but, whenever the government gets involved, as in offering rebates for energy savings, then it's time to take a look at the real world that they may not have thought of. (Can you say "Daylight Savings Time?")
So, let's say that half the population of a given neighborhood suddenly decided to go tankless. Since large segments of our population share schedules ( "rush hour" doesn't just happen on the freeway). So, what happens at 6:00 a.m. on a January morning when everyone hits the showers at once?
Here's a simple example: Let's say a distribution branch is designed to handle a hundred homes equipped with 45,000 btuh storage type water heaters. If just 10% of those homes switched over to tankless, at 190,000 btuh each, demand could result in a 25% increase in peak energy demand. In other words, just as individual homes have to be upgraded to accommodate the peak demand of tankless burners, the municipal infrastructure could have to be upgraded in order to provide enough energy for peak usage. Fortunately, the high up front cost of converting to tankless will prevent hoards of consumers from adopting these units but that doesn't change the fact that several tankless heaters on a single distribution branch could cause problems.
If you don't think this could happen, perhaps I should tell you about the challenges I've seen neighborhoods experience when severely cold weather resulted in every furnace firing at once. The gas company had to bring in tanker trucks of natural gas, pumping it into the local distribution system because the infrastructure couldn't deliver enough fuel gas.
I realize this is getting a bit far fetched but these infrastructure problems would be a real headache if the population in general decided to go tankless. It won't happen, as mentioned already, but it's still evidence that tankless isn't going to solve our energy challenges.
Speaking of infrastructure and payback. Last week, I mentioned that I had found a manufacturer boasting of 50% savings. Here's the phrase from their website in case you missed it:
"[Our brand] tankless gas water heaters provide an endless supply of hot water on demand; only heating the hot water that is needed. This performance cuts water heating costs up to 50%."
I asked them to help me understand the savings claim and sure enough, they have a real live case study where they replaced a 40 gal. NG water heater with their tankless unit. They had 6 months of before/after fuel costs for each water heater (I'm not sure how they gleaned that part of the data) and sure enough, they managed to squeeze out as much as 53% savings in a couple of the months. The six month average savings ended up around 45%. This is a pretty significant savings by any measure. Very impressive. But there's a hitch: That 45% savings results in a monthly dollar savings of. . .are you ready for this. . . less than $23.


At $23 per month, what's the estimated payback (in months or years) for swapping out a 40 gal. Nat. with a tankless unit from your shop? For calculations, use a tankless unit that's just under 200,000 btuh max input with a remote T-Stat. Be sure to include re-sizing gas and flue piping as would be typical in your area when working up your prices then send me an e-mail with your bottom line number: At $23 per month, how many months would it for a conversion to pay itself back?

[GrumpyPlumber]

Heya Mark, thanks for noticing...feast or famine here.
Got real busy about a month ago and been crazy since.
As for $23 a month, it's math.
Lets say a 40 gal tank costs $800 for install and a tankless costs $3K.
A disparity of $2200.
At $23 a month, thats $276 a year, $2200 in 8 years.
I better stop ignoring those Plumbiz E-mails..apparently I'm missing out.