Radiant heating as \"Green?\"

Chris S

I just finished the training to become a CGP (certified green professional). I am not an expert on this, but I do have the manuals. In order to qualify a home as "Green" the building

1. must comply with the International Energy Conservation Code or a local energy code which ever is more stringent

2. HVAC loads must be designed using mahual J or equivalent.

3.A third party plan review to verify compliance with the guidelines is required.

Because the course & the program place a high emphasis on energy savings via insulation strategies, tightening up building etc. there is a great emphasis on air quality.
In reference to hydronic systems, there is but a brief paragraph in a 50 page chapter. I think this is because most new construction goes with forced air.

The underlying goal is however efficiency, and so we get points for a properly designed, insulated, and installed high efficiency heating plant. This would include the use of low wattage circs and zone valves as mentioned above.
In the overall scheme of things however we lose point if these components are shipped over 500 miles because of the carbon footprint associated with shipping.

And (from the manual) the benefits of a green building include more comfortable, healthier & safer homes, with lower utility bills. So I would say then that Radiant Heat is "Green"

Jack Sweet

Radiant heating as \"Green?\"

Hi, everybody. It's Jack Sweet from Reeves Journal. I was hoping to take a few seconds of your time to conduct a very informal and unscientific survey.

Is radiant heating a "Green" technology as that word has come to be defined? Why or why not?

I know it's a very general question and it would all depend on the heat source used, etc., but what about your typical basic radiant hydronic installation? How does radiant heating fit into the universe of "green?"

Brad White_203

Lower

water temperatures for one thing, Jack.

The notion of using condensing boilers is a given for most applications, but with low temperature systems, solar, geothermal and other sources can be "pooled" into the radiant heating system.

If you are dependent on a higher temperature medium (in your emitters), there are very few hours when low temperature fluids -those in the 90-110F range- will work. With radiant floor heating, these temperatures often work well even on the coldest days, depending on the usual variables.

Even if you have a higher-temperature system (oil-fired or gas fired cast iron boiler for example), one can still save energy using mixing strategies, sipping rather than gulping the hot water generated, so long as your radiant surfaces (floors, walls or ceilings) can use the "cooler" warm water.

Personally though, I find the term "green" as over-used as "groovy" and "let's do lunch".

I really wish it were retired, unless we can start burning chlorophyll.

Dave Yates (GrandPAH)_11

spot-on

Those same lower water temps lead right to the heat source too & the lower the greener. Modcon boilers get greener as water temps are kept lower. These systems perform in shades of green and their shade of green is largely dependent upon the skills of the designer(s).

The flexibility of hydronic radiant heating/cooling systems, as Brad points out, give them the ability to be conjoined with virtually any renewable energy source for a blended green approach.

But, it's the delivery & heat emitter portion of the system that determines the shade of green. For example, a staple-up or suspended tube application may well require 180F water on a design day while a better design for the same room/space will work equally well with 85F water temps.

We typically expect to realize a 50% reduction (or more) in fuel usage when we green up an existing home or business with a modcon boiler and radiant heating (or free standing cast iron rads).

klaus

One thing I would really be curious to see is the difference between a slow responding system like radiant, using low temps, vs. a low mass system that is very quick to respond using setbacks during the unoccupied times.

Radiant obviously couples well with modcons because they love the low return temps, but between the addiitonal electric and all the controls, are you really using much less energy??

I'll be the first to agree that Radiant is a more comfortable system, but for someone like me and my wife who are out of the house from 6am to 8pm everyday, i would really question what kinda savings I might see.

GMcD

As Brad and others have said

Low exergy system, creates great indoor comfort = great indoor environmental quality. Can use renewable heat sources for low grade heating water, highly efficient energy transport system using water to carry energy around a building rather than large amounts of air. Properly installed and controlled it can use much less energy to maintain comfort compared to all-air systems.

Dave Yates (GrandPAH)_2

greening up the juice 2

My modcon draws just over 120-watts when it's on cruise control. Can't do much there due to the head-loss through the boiler, but on the other side, I'm in the process of getting rid of my more than 1,000-watts of multi-circs in favor of a low-watt variable speed circ and 3-watt zone valves, which will drop me from more than $400 per season to just under $30. A nice bit of conservation and given that our electric rates will all but double in 2010, I'm looking at more like $850 down to less than $60. I'll also be eliminating some controls and transformers/relays.

Yet one more shade of green.

Jack Sweet

So, I guess it would be fair to say:

--That radiant hydronic systems are "green"-er, depending on many variables.

--And there are components of a radiant hydronic system that could be considered "green" in and of themselves.

--And the systems can be used to complement the overall "green"-ness of a building as a whole.

--However, we probably won't be seeing radiant hydronic systems marketed to consumers as a "green" alternative the way we might be seeing that happen with other products, services, etc.?

Unknown

I would have to say

they are Green. After all the window companies call their LOW E windows Green and we know their is nothing further from the truth. They are the largest heat loss in the home. So compared to windows they are Super Green.
TONY

Andrew Hagen_2

Green

"Green" is the mist overused and misused term I can think of recently. Is a product green because it is low VOC, ie, are solid granite countertops greener than laminate because granite is natural?

I do not see anything about radiant heating as inherently green, although radiant systems certainly make it easier to take advantage of some other green products. What is truly green is the superinsulation that accompanies most good radiant systems. To save the planet and ensure our energy future isn't a scene from Mad Max, we cannot simply burn a lot of fuel efficiently. We must burn less fuel.

My opinion is that the greenest products allow us to conserve by using less while not detracting from our quality of life or significantly affecting our way of life. Solar panels are an excellent example, because they can supplement our energy consumption without any interruption of service to the end user. Corbond insulation is also a very green product. CFL's are green. Energy star appliances are green. Accurate thermostats are green. Properly designed radiant systems fit with these green products very nicely, but I feel "properly designed" has to be the baseline upon which "greenness" is measured.

Proper design and installation is the green part of any heating system.

rb_6

the inefficiencies of delivering efficiency

My 40 grit comment…until the inefficiencies of delivering efficiency are corrected - no electromechanical or building component/system should be called green/sustainable/efficient or any other word that prevents us from looking hard at the combined use of power, fuel and subsequent emissions and wastes from mining, component manufacturing, transportation, distribution (imports and domestic), local transportation/ installation/assembly, maintenance and final disposal of so called “green” products and systems.

Just because we can’t see or choose to ignore the “ungreen” elements of manufacturing a product or fabricating a system doesn’t mean its “green”.

humbugger bean

scott markle_2

my 2 cents

Many of us can agree that a major realignment of our priorities is required to avoid further diminishment of our natural world.

Green is about refocusing our lens to see our context in the living world.

How efficiently we heat a structure does not need to be hitched to a world view, It's just a sensible endeavor.

Radiant energy is a component of any emitter. A generously sized panel radiator operates largely in the radiant "spectrum".

Trophy second homes are intrinsically unsustainable, Some will be engineered and executed better than others, this has little to do with how green they are. "You can't have your cake and eat it too". If something is in contravention of the ideals of sustainability no level of efficiency can make it green.

Does the Hippy in his tepee need third party review to prove compliance?

Tony, in regards to the greenness of low e glass I would strongly disagree. Just because it's a bit loose with your precious btu's don't disregard what that window brings in. We can quantify the lumens and btu's , but beauty is not a metric. A windowless foam box could be configured with a heat pump, HRV, radiant slab, net metering and a bunch of silicon. This house is net zero, but is it green?

Mark Eatherton

I tire of the use of the term \"Green\"....

In fact, I don't use it. Most of the people responding to this question have been doing the "right" thing for years, and that may include solar, GSHP, and in most cases uses radiant as a method of delivering efficient comfort.

The term radiant, as known by most knowledgeable people in the comfort business, drives the bus of human comfort. Properly applied, it CAN deliver the goods. Improperly applied, it delivers misery, and poor efficiency. Is it green? It can be, or it it can be black.

So, the only correct answer, as is the case with any hydronic question, is "It depends", but you already knew that ;-) It starts with good sound design, good building science and good installation practices, and finishes with an efficient system with happy, healthy occupants.

ME

rb_6

Green photo

While doing research for an upcoming presentation on sustainability I shot this photo of a roof top unit supporting green growth...something profound about it...

Andrew Hagen_2

Throwing out the baby with the bath water...

The more readily the average person will accept a product or practice that reduces energy consumption factors in to how green I personally view it to be. We can offer the greenest products and practices available, but if few adopt them is it better than if many people will adopt something slightly less green? We need to get people started down the path somehow, and I think that pushing things that are "too green" too soon will tend to push people to reject anything green at all.

For now, I am willing to accept inefficiencies in the manufacture of products that save energy in the long run. That sure beats the alternative of skipping it altogether, which I believe is still an alternative in many people's minds. History has shown that without high energy prices, energy conservation goes right out the window. To me that demonstrates how tenuous the green movement really is.

hb_9

Green Radiant

Lately, the only green in radiant I have seen is the money I make repairing deficient "systems".

While you may not always get what you pay for, you never get what you don't pay for.

Bob Bona_4

Amen, Mark. nm

scott markle_2

The bean perspective

First thing that came to my mind after seeing this post was the RB. Glad he is weighing in.

Not sure how the Bean reconciles consulting for the luxury market with the ideals of good stewardship. I'v put this question to ME in regards to snow melt etc. I believe social issues (distribution of wealth) are inseparable from the question of sustainability.

Efficiency and Green are different things.

I like the cradle to grave analysis that RB is advocating, although I think the calculations can quickly become quite abstract. Let the "bean-counters" focus on this as opposed to selling more widgets.

Dave Yates (GrandPAH)_11

yeah, what he said!

Green-wash is white-washing everything - just as did the term hybrid until that too meant so little no one paid it any attention anymore.

Like ME said, we've been as green as green gets before green became the latest buzz-word. From a pro's perspective the term green has already been bastardized, bashed, and put away so bruised it's become more black-and-blue than green.

We have no system in place to adequately judge the green-ness of our mechanical systems, so it boils down to the integrity of the individuals - from initial designs to finished operational system. The green standard-bearers remain focused on individual components. If we ever accept building performance ratings that take into account all aspects of mechanical systems performance (as is being done in Germany), the benefits of real-world conservation (green) will be blantantly apparent and our work will be seen as having real value - cream rising to the top, as it were.

Brad White_203

To the points made:

1) Yes, I would say that radiant hydronic heating is (ugh) "greener" than other forms of heating requiring higher temperatures.

2) Yes, many components are considered "green", such as the use of ECM motors, PEX and PEX-AL-PEX if those should be made of recycled materials, the fact that a concrete slab can do double-duty as a radiator (saving metallic emitter total embodied energy costs)... all true as applied. But one has to apply them correctly and get them on the job first.

3) By definition of the question, radiant heating, heating in general, is but one component. No real point in installing an ultra-efficient, low-energy system in a building that leaks like a sieve. They both work together.

4) Marketing: When we are brought in to design a project with LEED applicability or "like LEED", one of the first suggestions we give from the HVAC side is the possibility of using radiant floor heating where it is practical.

Seldom does it make it to the end design, alas. But in terms of marketing, it is one of the first arrows in our quiver to which we reach. But as you allude, heating, HVAC in general, is only a segment of the "verde" spectrum

Jack Sweet

This is great stuff everybody, thanks. Would there be any problem with me using some of these statements, attributed to HeatingHelp.com USER NAMES, in a short article?

It would look something along the lines of:

Users of the popular HeatingHelp.com Web site's discussion forum called "The Wall" say, blah blah blah.
"Blah, blah blah," said a user going by the screen name of of Hothotheating. "blah, blah, blah."

klaus

I agree w/ the other guys

Radaint has more potential to be green than most options out there. blah, blah, blah, blah, yada, yada, yada. (-:

Metro Man

greeness

What we have seen by the years of refinement and technological advancements in the radiant heating industry is what has been mentioned on this thread. Lowering the delivery temps to radiant heated buildings has created very efficient heating systems. This works well with the solar heating systems that we design. Delivery temps as low as 80*F can be realized from the solar heating and boiler system even on design day conditions. Combined with a properly designed storage system and a home can be heated for several days without firing the boiler back-up heat. I guess you could call that green.

It all goes hand in hand.... tightly built homes, properly designed heating systems, and educating homeowners.

Just finishing a 7500 sq ft solar/mod-con radiant heating home. Heat loss came out around 95 MBTU's. Had to run the numbers 3x to make sure. Concrete slab, gypcrete, var. speed pumping, continuous circ, etc... make this all work.

Metro Man

Chris S

an excellent point

The "points" alotted - only apply to the afue of the unit. energy star rated makes you green.

All the stuff that happens between the Supply and return pipe isn't even looked at.

Same goes for forced air. They want AFUE , or high SEER, and seal the leaks in the ducts, but what about all of the poorly designed & installed duct systems?