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). I am hearing about possibly a more efficient way using two 90% efficient 60 gal water heaters.
Can anyone make some suggestions to me? I live in Northern Colorado.
Project description:
42 x 80 Pole style building, single level (metal siding + metal roof),
12 ft side walls
FLOOR: 1 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
It is possible to make hot water heaters work with radiant flooring but in most cases the duty cycle is far greater than the hot water heater was ever intended for. You can figure what that does to the life expectancy.
Is this a troll, 16800 Btu has to be a typo, you do mean 168000 I hope I hope. You want efficency and you discuss 85% efficent boilers when up to 98% are made !! What boiler are you looking at.
Tell us all who makes a 90% efficent tank water heater... Answer nobody makes a 90% efficent fossil fuel water tank. Learn about EF- Energy Factor ratings, and show us the tank. And a tank isnt designed for long life but it truely aint efficent.
1.5" Blueboard is R 7.5,, 1.5" foil faced Polyisocyanurate is R
10.5 with an added radiant barrier, which is still not optimal R value for concrete radiant heat.
Walls R 26, Ceiling R38, it sounds off. What is construction and type of insulation You have lots a learnin to do wilma fingerdo, cause someones lyin to you.
He did qualify it as being "fossil fuel" powered and electricity may come from hydro or nuclear and thus not be fossil fuel. However, I provided a link to a fossil fuel unit that was still well above 90% efficient.
Polaris, Ao Smith, condensing, are not 94-96% efficent.
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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 !
Boilers 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.
EF is not a rating Tank manufacturers publish often, or like to talk about, because it highlights tank limitations in true efficency
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.
The last I read Energy Star is still working on a tank specification.
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.
Learn about Certified, EF Tank ratings, from the Government at
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EF is how a tank is rated, AFUE is a boiler rating, SEER is AC. That "well above 90% efficent Polaris" I bet is near 83-85% EF as is my Condensing $2000.00 AoSmith. Look at AoSmith, Cyclone and Vertex line, the same top end stuff as Polaris. My last Ao lasted near 20 years in commercial heavy use, AoSmith is a top commercial manufacturer. To heat a house even more efficently, get a domestic water heater built to it, or use a Condensing 93 % 93EF ! Takagi Ng tankless. And then there are more options.
Ah thanks. We would call them Boilers or central heating boilers.
Since April 2005 all gas boilers in the UK have been condensing types. Non condensing types can only be about 88% efficient but condensing types can be
90+% efficient..
Example:
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The oil boiler I have is 92-93% efficient...
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but there are different ways to calculate efficiency. This explains how to get a headline rate of 102% ...
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How do running costs compare for electric, gas, oil in the USA? We have a comparison site here...
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For what it's worth it assumes 90% efficiency for a gas boiler.
I guess they aren't mandatory in the US? In the UK all new installations or replacement boilers (tank heaters) have to be condensing. Been like that since 2005.
England an energy Exporter has had the foresight to mandate condensing heat units, here in the dumb ol USA 83% efficent is still pushed because installers like the "easy" instal and idiot homeowners are to dumb to do the math, its a joke, we import oil and we allow 83% efficent heat. Water heater tanks are just one reason we as a nation use a majority of the world energy by % of population. Its a fact, in new construction a hot tub is more common than a high efficency heat plant.
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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