PV vs CV water heaters?

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Unknown

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Dec 21, 2006, 11:28:53 PM12/21/06
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So what do you guys think about the water heater debate? I
constantly get customers who have paid big bucks to have their home
audited and tested for efficiency ect...They tell the customer to
replace their conventional vented water heater with a power vented
one. I think a lot of people assume the power vent is high
efficiency because of the plastic vent. It doesn't condense so
obviously it's not. I have tested both using flue gas analyss,
found they run 75-80%. The power vent needs 120v though, so I lean
towards the PV actually being less efficient. Faster recovery time
though, lower input...so I dunno , confused...

What do you guys think?

-CanadianHeat


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jamesgangnc

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Dec 22, 2006, 8:42:26 AM12/22/06
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Tankless gas is less efficient at heating the water. If the usage is
infrequent then the savings from not having to keep the water hot
outweighs that. In a normal household that is not usually the case.
There is the added advantage of never running out of hot water though.

Bubba wrote:


> On 22 Dec 2006 04:28:53 GMT, DANgER (dan...@heat.com) wrote:
>
> >So what do you guys think about the water heater debate? I
> >constantly get customers who have paid big bucks to have their home
> >audited and tested for efficiency ect...They tell the customer to
> >replace their conventional vented water heater with a power vented
> >one. I think a lot of people assume the power vent is high
> >efficiency because of the plastic vent. It doesn't condense so
> >obviously it's not. I have tested both using flue gas analyss,
> >found they run 75-80%. The power vent needs 120v though, so I lean
> >towards the PV actually being less efficient. Faster recovery time
> >though, lower input...so I dunno , confused...
> >
> >What do you guys think?
> >
> >-CanadianHeat
>

> I didnt know there was a debate.
> Power-vented doesnt save money over atmospheric.
> The power-vented is usually twice as expensive as the atmospheric.
> Go with a tankless.
> .............and No, I dont have one........yet.
> Bubba

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jamesgangnc

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Dec 22, 2006, 9:33:04 AM12/22/06
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I didn't mean to suggest it was unlimited by saying endless. Within
it's gpm limitations a tankless will go on delivering hot water for as
long as you want. It won't "run out" because it keeps heating new
water. You can draw 2 gpm for as long as you want. You might run out
of money to buy the gas though :-)

Steve Scott wrote:
> The endless hot water thing is hype. Any WH can run out of hot water.
> A 100kbtuh WH will only deliver a little over 2gpm continuous flow at
> a 75F temp rise.
>
> On 22 Dec 2006 05:42:26 -0800, "jamesgangnc"

> --
> Keep your feet close to the ground.

Victor H Plank

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Dec 22, 2006, 2:43:32 PM12/22/06
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"Bubba" <LiKeAlA...@iname.com> wrote in message
news:rvmno29r7ptt4dhdp...@4ax.com...

> On 22 Dec 2006 04:28:53 GMT, DANgER (dan...@heat.com) wrote:
>
> I didnt know there was a debate.
> Power-vented doesnt save money over atmospheric.
> The power-vented is usually twice as expensive as the atmospheric.
> Go with a tankless.
> .............and No, I dont have one........yet.
> Bubba

Bubba:
About 8 years ago I replaced existing gas water heater with a power vented
gas water heater. Same capacity and same BTU input. Youngest daughter was
senior in high school. Gas bill dropped about 15% taking degree days and
such into account. When she went to college the next year gas bill dropped
another 5%.

Just speaking from experience.

Cost was about $100.00 more than regular vented.

Merry Christmas

Vic


Bob_Loblaw

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Dec 22, 2006, 3:56:41 PM12/22/06
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"jamesgangnc" <james...@earthlink.net> wrote


> Tankless gas is less efficient at heating the water. If the usage is
> infrequent then the savings from not having to keep the water hot
> outweighs that. In a normal household that is not usually the case.
> There is the added advantage of never running out of hot water though.

When water is heated, the minerals drop out of it.
Tankless heaters get a build-up of minerals much like a persons veins do
with hardening of the arteries.
They should be flushed out with a vinegar solution every year(the tank, not
your veins.Veins should be flushed with copious amounts of Stella Artois).
This is just one more reason to stay away from them.
If you place your hand on the side of a conventional type of tank ,you will
notice that there is very little heat transfer due to the high insulation
value of most tanks.
Turn off your water heater and you'll still have hot water 8 hours later.
Tankless heaters are popular in Europe mostly due to space constraints.
They are not a good idea unless you need the extra room.

--
Respectfully, Bob

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chiggorrt

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Dec 22, 2006, 7:44:00 PM12/22/06
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Goddam Canadians

Unknown

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Dec 22, 2006, 11:08:37 PM12/22/06
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I've taken some training on a rinnai tankless. I wondered how well
they would hold up. Japaneese seem to have built a good machine from
what I saw. I have yet to get to install or service one though.
Thanks for the input about them Bob. I guess maintenance will be
the big issue.
Vic your numbers are useless for my original question. I don't pay
for gas so I never really get a chance to see LOL

Jeffrey Lebowski

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Dec 23, 2006, 12:05:14 AM12/23/06
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"Bubba" <LiKeAlA...@iname.com> wrote in message
news:upnoo2lab6isagv66...@4ax.com...

> Water heaters are out of sight anymore.

Here, the electric ones are quite commonplace...

Funny thing, I had packed one from an old rental place around for nearly 25
years...cause I was in a hurry to replace it....and was no time to
troubleshoot at the moment...

Well, the heater recently went out in the shop, and so finally the time
came--and I found a loose wire there where it attaches to the lower element.

Total cost= FREE (plus yesterday's alrerady spent dollars )....

--

AKS

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Dec 23, 2006, 11:15:11 AM12/23/06
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Question: what happens with furnace when vent fails to open??????
from Dido

"DANgER" <dan...@heat.com> wrote in message
news:458b5f05$0$22679$9a6e...@unlimited.newshosting.com...

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Bob_Loblaw

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Dec 23, 2006, 2:36:08 PM12/23/06
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"AKS" <a.s...@verizon.net> wrote

> Question: what happens with furnace when vent fails to open??????
> from Dido

What furnace has a vent that closes?
If you're refering to a vent damper, then you shouldn't have a license if
you don't know the answer.


--
Respectfully, Bob

Oscar_Lives

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Dec 23, 2006, 9:41:52 PM12/23/06
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"Bob_Loblaw" <inocent...@hotmail.com> wrote in message
news:Iyfjh.18706$Ca.1...@read2.cgocable.net...

No, he is talking about the return vents on the upper level that he closes
to help the air conditioner cool better.

I figgered that he thinks that the "cold air return" vents will let all the
cold air return to the lower level, so he wants to trap it upstairs.


Bob_Loblaw

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Dec 24, 2006, 1:07:30 AM12/24/06
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"Oscar_Lives" <nos...@nospam.net> wrote


> No, he is talking about the return vents on the upper level that he
> closes to help the air conditioner cool better.
>
> I figgered that he thinks that the "cold air return" vents will let
> all the cold air return to the lower level, so he wants to trap it
> upstairs.

Honestly, I doubt even he knows what he means!! LOL

--
Respectfully, Bob

AKS

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Dec 24, 2006, 9:49:24 AM12/24/06
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If you two can see beyond tip of nose you would understand
that my "question" was not question it was comet.
but your knowledge is overtaking by selfishness and arrogance
Have happy holiday Gents
Dido

"Oscar_Lives" <nos...@nospam.net> wrote in message
news:QNljh.1106906$084.926259@attbi_s22...

Oscar_Lives

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Dec 24, 2006, 11:41:27 AM12/24/06
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"AKS" <a.s...@verizon.net> wrote in message
news:Urwjh.509$Ej7.105@trnddc02...

> If you two can see beyond tip of nose you would understand
> that my "question" was not question it was comet.


Stormin' is the one with the comet. Go to his house-- the comet train
leaves in a few days...


> but your knowledge is overtaking by selfishness and arrogance
> Have happy holiday Gents

> Dildo


Hey Dildo,

For the Christmas holliday,
GO FUCK YOURSELF ASSHOLE!

wdge...@rogers.com

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Jan 4, 2007, 2:57:14 PM1/4/07
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Finally some good advice re tankless wtr htrs. The reason they have a
problem with mineral clogging is because of how they work. They
regulate the flow and pressure to ensure that the water comes out at
120 F for example. When you heat water and change the pressure,
minerals tend to drop out. Ground/water source heat pumps can also
have that problem.

Tankless water heaters require very high firing rates, at least in the
north where the entering water temperature is 50 F or lower, to give
us the amount/volume of hot water most people are used to. In many
cases, around 200,000 Btuh or more is required to do that. In many
existing homes the gas piping will not accommodate this along with a
gas furnace and other appliances without a piping up-grade, adding
further to their already high cost.

The standby losses through the tank walls for a conventional or power
vented gas water heaters is about 6-7%. Most of that loss is inside
the building envelope and in many areas reduces the normal heating
load of the furnace. During the AC season it can add to the AC load,
a minor problem in the north and a non-issue in most homes with
basement installations.

It is also difficult to find a service contractor who knows how to fix
the ductless units, especially since there are so many brands out
there. I also imagine parts availability can be a problem in many
areas. Part prices may also be very high.

Most people that try the tankless water heaters are not happy with the
flow rate they get. We have often had to remove many of them and
replace them with a regular PV model.

Where I live, the average family spends about $350 a year for gas hot
water heating. Conventional gas water heaters can be installed for
somewhere between $600 and $700. A tankless water heater might save
$150 a year in this example. At that rate, the payback period will be
quite long, not even counting the annual acid flush and other repairs
that WILL be necessary over its life. Very little goes wrong with a
conventional water heater - we ought to know as we rent out well over
a million of the things.

Having said that, one day in the not to distant future, I will think
we will see them become the norm in new construction, especially as
the short comings get addressed.

daytona°

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Jan 4, 2007, 7:38:57 PM1/4/07
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You have a very good point. BUT in alot of cases for us, we have installed
TWH's for unlimited hot water usage. Took out (2) 50 gal atmospheric HWT's
(in a LARGE house) and installed (1) Noritz N-132M (13.2 gal per minute) The
Dr wanted the biggest. He had 5 baths (3 whirlpool tubs) 5 children and the
story goes on. Installed with the option flush kit and remote controller.
Ended up with all hot water taps opened with 132° at all taps. Dr happy and
paid the bill (cash). We have been once to flush appliance...routine
maintenance. He has said his gas bill is down and the consumption is also
down. Maybe a few of the kids moved out :o)

<wdge...@rogers.com> wrote in message
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wdge...@rogers.com

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Jan 20, 2007, 8:33:23 PM1/20/07
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That Noritz unit must have a whopper of a firing rate? What is the
Btuh input? There was no doubt once we got past the tiny output Euro
models, with good reliability and a big enough gas line, these
instaneous water heaters would be the way to go. 13.2 gallon per
minute at what incoming water temperature. We run about 45F or less
here in winter and 50F in summer.


On Thu, 4 Jan 2007 19:38:57 -0500, "daytona°" <HV...@excite.com>
wrote:

Elocin

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Nov 24, 2021, 10:01:38 AM11/24/21
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I’m looking to change from chimney vented to power vent and the rental per month goes up from $17 to $35, plus tax is there a huge saving?

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For full context, visit https://www.homeownershub.com/hvac/pv-vs-cv-water-heaters-10382-.htm

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