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Posted by ransley on December 4, 2008, 6:39 am
> ransley wrote:
> >> ransley wrote:
> >>>> ransley wrote:
:
> >>>>>> In a hydronic floor heat system, what is the best way to heat the =
water
> >>>>>> in the pex tubing?
> >>>>>> The initial study of the building design recommends a 16800 BTU 85=
%
> >>>>>> efficient boiler ($2000 US). =A0I am hearing about possibly a more
> >>>>>> efficient way using two 90% efficient 60 gal water heaters.
> >>>>>> Can anyone make some suggestions to me? =A0I live in Northern Colo=
rado.
> >>>>>> Project description:
> >>>>>> 42 x 80 Pole style building, single level (metal siding + metal ro=
of),
> >>>>>> 12 ft side walls
> >>>>>> FLOOR: =A01 1/2" "Blue board" foam insulation on top of pea gravel=
- 5"
> >>>>>> concrete slab w/ pex tubing on 12" centers - 3 zones (3750' of 1/2=
"
> >>>>>> tubing in approx 250' runs
> >>>>>> INSULATION: Walls- R-26 -- Ceiling- R-38
> >>>>>> Thanks!
> >>>>> =A0 =A0Is this a troll, =A016800 Btu has to be a typo, you do mean =
168000 I
> >>>>> hope I hope. You want efficency and you discuss 85% efficent boiler=
s
> >>>>> when up to 98% are made !! =A0What boiler are you looking at.
> >>>>> =A0 Tell us all who makes a 90% efficent tank water heater... Answe=
r
> >>>>> nobody makes a 90% efficent fossil fuel water tank. Learn about EF-
> >>>>> Energy Factor ratings, and show us the tank. And a tank isnt design=
ed
> >>>>> for long life but it truely aint efficent.
> >>>> You seem pretty sure of yourself ... for being wrong.http://www.amer=
icanwaterheater.com/products/pdf/lpg100.pdf
> >>>>> =A0 1.5" Blueboard is R 7.5,, =A01.5" foil faced Polyisocyanurate i=
s R
> >>>>> 10.5 with an added radiant barrier, which is still not optimal R va=
lue
> >>>>> for concrete radiant heat.
> >>>>> =A0 Walls R 26, Ceiling R38, it sounds off. =A0What is construction=
and
> >>>>> type of insulation You have lots a learnin to do wilma fingerdo, ca=
use
> >>>>> someones lyin to you.
> >>>> More than one person is lying to Wilma.- Hide quoted text -
> >>>> - Show quoted text -
> >>> I see your as dumb as her if you dont know facts. Gees, what ignorant
> >>> folks believe.
> >> What part of the Polaris efficiency specification did you not understa=
nd?- Hide quoted text -
> >> - Show quoted text -
> > Polaris, Ao Smith, condensing, are not 94-96% efficent.www.energystar.g=
ov
> > publishes efficency ratings for all tanks made. Efficency of a tank is
> > rated as EF or Energy Factor, the number rating of 85 means 85 cents
> > of every dollar you spend heats the water. I have a $2000.00 Ao Smith
> > Cyclone condensing tank of thermal and burner efficency of 93% but its
> > EF rating is about 83, and all boilers are at least 82% efficent
> > today. 95 or so % of all Tank water heaters sold today in the US even
> > the ones labeled High Efficency are in fact only 55-65 EF. The
> > government still hasnt set a standard yet, its a scam to the
> > uneducated. The lowest gas tankless is 83 EF and a condensing Takagi
> > is 93EF. that is the highest efficency water heater I know of made
> > today, so what you see is most always no better than 55-65 EF or 45-55
> > cents of every dollar you spend heating water goes up the chimney !
> > =A0 =A0Boilers can be much more efficent, the AFUE ratings reflect use,
> > like EF rating does on tanks. There are many 93-96% efficent Ng
> > condensing boilers out, that are the best for Radiant tube sine
> > Radiant uses realtivly low water temps and Condensing boilers drop
> > dramaticly in efficency at over 140F, there is one I know of from
> > canada that is AFUE 98% efficent, and the best tank is maybe 83 EF
> > that I know of.
> > =A0 EF is not a rating Tank manufacturers publish often, or like to tal=
k
> > about, because it highlights tank limitations in true efficency
> > =A0 OP doesnt discuss Condensing units, but is in fact looking at 83%
> > boilers, when 96 is easily avalaible, and most likely is looking at
> > Two, 55-65 EF tank, now thats a waste of money. First 2 tanks would be
> > less efficent than one and she doesnt need 2, but tank are not
> > designed to last as home heaters.
> > =A0 The last I read Energy Star is still working on a tank
> > specification.
> > =A0 Op is best with a 96-98% AFUE condensing boiler, not a 55-65 %
> > efficent water tank made for showers. Find the EF rating on Polaris
> > and post it, Ao Smiths site wont post all EF numbers on their super
> > expensive Condensing units, but I own one.
> Sure, you can define and redefine efficiency any way you want. =A0You
> simply said "efficiency" in your post, you didn't say "energy factor."
> I could also redefine "efficiency" as total energy leaving the ground
> vs. what ends up as heat in my water tank including the energy required
> to extract and transport the fuel to my house and then claim that water
> heaters are only 30% efficient. =A0If you want to play definition games.
> Overall system efficiency is not a simple equation and should include
> economic efficiency as well. =A0Often the extra cost of the ultimate
> highest energy efficient boiler or furnace isn't justified economically.
> When I built my house I went with a 92% efficient (AFUE) furnace vs a
> 95% for two reasons:
> 1. The cost delta was substantial at that time and the payback period
> would have likely exceeded the life of the furnace.
> 2. The contractor told me that the newer furnace had been very
> troublesome compared to the 93% model which had been on the market
> several years longer. =A0Apparently, the variable speed motor and variabl=
e
> flow gas valve hadn't yet been fully sorted out from a reliability
> perspective.
> Using a water heater sounds odd for a building of the size the OP is
> looking at, but if there are other needs for a large water heater
> anyway, then using a large water heater vs. a boiler and a water heater,
> might make sense economically. =A0Then again, maybe a boiler with a heat
> exchanger to heat water for non-heating purposes might make more sense.- =
Hide quoted text -
> - Show quoted text -
I did not say Energy Factor, wait one minute, I am the ONLY person to
talk EF
Sure my heat guy said condensing is an issue, his stupidity was the
issue.
Show me one study the states condensing wont pay off, I mean wake up,
at a minimum you get 10% savings.
How many folks here have tankless water heaters in the US, Naw you
guys are all to smart for those. I have one in my house and in summer
my gas bill went down from 45$ to 9 month, mine was a 450$ Bosch, I
get a 4 yr payback and its maybe 6yrs old now
The only way a 55-65% efficent tank makes sense is if you are dumb,
and you cant drink or shower from water for heating so if OP has 2
tanks to heat the OP needs a 3rd unefficent junk to heat water.
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