Radiant Heat isn't about the feet....

Unknown

Actually you're wrong John

Ask any Levittown homeowner who converted from the original radiant floor to baseboard heat and everyone , I mean every one of them miss the warm floors the most .

Playing on the floor with your toys or dog as a kid , playing with your kids on the floor later on in life , using the bathroom with just socks on or bare feet when it's 20 degrees out - there is no better feeling once you lived in a radiant floor home .

Marketing guys hurting the reputation of radiant heat ? My opinion is the marketing guys have it dead-on . Is your beef with the marketers that they tout the warm toasty floors first in the sales pitch and explain the other benefits later , or do you think they keep it simple with the one benefit of radiant ? Which marketers are you referring to ?

John Ruhnke

Low E homes.....

Ron,

This post came about from the comment on low e homes. People are saying that because the floors are cooler radiant isn't a good option. They miss the point. It is a radiant heating system not a conduction heating system.

Yes if you have an old drafty house like in Levitown, warm floors are nice. I never said that warm floors weren't nice That is heat by conduction not radiation. It is a very good byproduct.

On most systems that I design, the average temps are 75 degrees. If you walk barefoot, it will be a little cool of course still warmer then with hot air. The comfort comes when relaxing in a chair. You don't feel to hot or too cold just nice and comfortable. The comfort comes from the radiant part of the heating system.

JR



Didn't you feel the same things?

JR

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S Ebels

Not to nitpick here but.........

Hot air does indeed rise by virtue of the fact that it is lighter than "cooler" air. This is an immutible law of physics.

Radiant heat does not "rise", it travels 360* from it's source.

The issue of radiant heat causing stratification is encountered in lot's of poorly designed systems. These are usually where the effective radiant area has to be driven to an unrealistic surface temp in order to adequately heat the space. The overly "hot" surface heats the air which then, because it is lighter, rises.

Ever ponder how the heat from the sun travels 93,000,000 miles through -400* space and warms the earth.

Clue: It ain't forced air!

Unknown

How many

Low E homes are being built or renovated to be low E homes in the United States ? How many are actually using radiant heat ?

Are you saying marketers are hurting the radiant field because the " warm , toasty floor " slogan should not apply to this very , very small share of the radiant market as a whole ? John , I follow your posts regularly and the gist of this one , if I follow it right , seems overblown .

Mark Hunt

Ron

Can I take a stab at this?

You asked, "How many Low E homes are being built or renovated to be low E homes in the United States?".

The answer is...........3?

You make a good point.

I understand now what John was getting at though he did not do a very good job making the point earlier.

I rarely see a floor temp above 75 degrees for most of the new homes we install systems in. That does not make them "low E" necessarily because if I went back and did a blower door test they would leak quite a bit.

We have an area in our neck of the woods that I have mentioned to you before where the houses are identical to the Levitt homes you see so often. The floors in those homes get pretty toasty in the winter since they are seeing 120 degree water when the heat calls. If you want to hear something really neat, you should tag along with me when a customer that chose the cheap guy for the change-out calls complaining of over-heating. I have seen instances where the new boiler was set to run at 180 degrees, "Like the good Lord meant them to run", and floor surface temps so hot you could not walk on the floor. OUCH!!

I also agree that when those poor copper tubes give up the ghost,(usually not long after they see 180 degree water for a while)and the H.O has to abandon the system for baseboard, they REALLY miss those old warm floors.

I have radiant in my home. Kidz luv it and so does the wife. What more is there for me to worry about?

No question about it, people like the idea of not having to wear their winter boots when they walk into the bathroom on a cold winter morning or feel like they are ice fishing when they are cooking in the kitchen. (I secretly enjoy losing all feeling in my feet when I am ice fishing...beats freezing!)

Mark H





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Fred Campbell

Can't We all just Get Along?

Guys, guys,guys,...why must some of us be so closed minded here. I'm not an engineer. I design and install well thought out, forced air systems AND hydronic systems for a residential market. A well designed forced air system can and will keep the people comfortable. Any misconception that 140* blasted into a space through a couple of ill placed supply registers with equally inadequate return(s) constitutes forced air heating...well, that's just what it is, a misconception.

We all know radiant heating, be it floor, cieling, or wall really is the most comfortable, even tempered (bit my tongue) way to heat a home. High temperature radiation/convection/forced air will stratify and cause varying degrees of stack effect. If a well insulated house is warmed to 68 or 72 with a 76 or 80 floor, you'll get more stack effect from the chicken soup cooking on the stove than from the heating system. With the reintroduction of 9 and 10' cielings in some houses does the owner really need to pay to keep the cieling area at 85*? Change a light bulb at 10' in a forced air or high temp convector/radiator vs. radiant floor and you'll know what I mean.

Well designed forced air systems know ALL about stack effect and redistribution of over heated or over cooled air. I'll still sell radiant based on the above arguments but I'll also design and install a forced air system that works for the user, and works for me.

Just HAD to add my .02

TG

PS. I'm not even gonna get into IAQ and humidity control

Tony_23

Fiction ?

Can you explain your statement about the numbers being BS ?

The ceiling temps for FA are probably embellished a bit, at least when the system is off, but the temps for radiant are pretty close to my experience.

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Mark Hunt

BAM!!!!!!!


Give that man a dollar!!

Second best reply on this thread TG!

First was the tragic story of the plane crash in Poland.

Mark H

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Kevin__Flynn

Tim

In response to your BS statment about the radiant vs. forced air diagram, I would respectfully have to disagree.

Suppose our radiant system keeps our floor surface temp at a given time at 78 degrees in a room that is trying to maintain 68 degrees. Now typically where we would like it to be 68 (70, 72 depending on the person) degrees is somewhere in the vicinity of our head. So, again it is 78 degrees at the floor now the floor starts to give up its heat to the surrounding cooler air and objects. This air now starts to rise slightly, but remember we only started out with 78 degrees so as the air rises it continues to give up its heat to the surrounding objects and the air begins to cool and become heavier. I'm sure you'll agree with the law of thermo-dynamics that says that heat goes to cold in any direction(paraphrsing slightly). Oh, and there is also that little rule of warmer air rising. The issue in the radiant system is that once the air has given up its heat it eventually becomes cooler than the surrounding air, therefore heavier, and is no longer able to rise.

Where this principle becomes most efficient is in buildings with high ceilings exposed to the outdoors. This is again, because the temps at the ceiling, especially a high ceiling are lower than that of a system that relies on higher temperature and moving air (slow or fast). This of course, reduces the delta-T between the indoors and the outdoors, slowing down heat transfer. (that darn hot goes to cold thing again) This, I will admit, is not as much the case with 8' ceilings with conditioned space above.

Now, if you are able to discharge your warm air registers into the room at 78 degree air temps low to the floor you may have a point. However, my guess is that the size of the ductwork and registers that you would need to accomplish this comfortably would be cost prohibitive.

As far as your comments about FHA being much more flexible when requiring humidification, HRV, air cleaning, A/C, etc... I would aggree, these things would certainly be more costly to add to a house with radiant heat. However, I don't by a chain-saw so I can also use it for cabinet making!!!




Kevin Flynn

Fred Campbell

Thanks Mark

Common sense does come in handy once in a while.

John Ruhnke

I was trying to make a point.........

Ron,

I will agree with Mark that I didn't do a very good job. It was in reference to some other posts that people said radiant wasn't a good choice because the floors were not noticabally warmer. I have that problem upstairs in my new addition. The addition is very comfortable though. I Take that back. They aren't hurting the industry. I shouldn't say that. Warm toasty floors is a good slogan. I think that radiant has more to offer then just warm feet. We need to explain in more detail the comforts of radiant. We need to prepare some of the homeowners for the fact that if you step barefoot on the floor you may not notice the floor being warmer mostly in the spring and fall. The house is still more comfortable though.

JR

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Mark Hunt

e house

is that something you get on e-bay?

Mark Hunt

relyable

is actually spelled reliable, but who notices spelling?

Bob Bona_4

I agree

I totally get what John is saying. He is just re-inforcing the point that floors need not be "warm" to the touch to make the space comfortable. It's all about equillibrum (sp?)..body temp vs. surroundings.

Far as I'm concerned, ductwork is great for IAQ, and cooling. Humidification not much of an issue with hydronics. Some situations make HA more practical, unfortunately just as a house on slab makes radiant a practical choice.

I know John personally ( he lives next town over) and the man is passionate about details. Don't get hung up on some mis-spoke phrases (typical of genius)-look at the gist of his posts.

You go, John!

Bob Bona_4

right on kf

I'd hate to toss my Wirsbo CDAM in the trash. Propoganda? I think not.

scott w.

coal furnace

Just remembering Grandma's old coal furnace with the floor registers. They were great to stand on after coming inside on a cold winter day after she had just stoked the fire. The old heat would just pour out of those old register and warm your feet to your butt. Of course you would just about smother when changing a light bulb in the ceiling fixture.

Bob Bona_4

think he

is saying that marketers push the warm floors thing hard, and can leave the consumer with unrealistic expectations.

But, in their defense, it grabs the consumers attention faster and better than a lesson in physics..that can come later once a design is done, and the consumer is made to understand how radiant heating works.

I have 1/2 my house done w/ QT panels..hardwood and tile. On certain days, a neutral feel is all it takes to meet the heat loss. I'm not cold, not hot, just "am":)

That's the beauty of radiant!

Gordy

Phantom proof reader

Love the edit button better now? Go back to Ebay.

Gordy

Brad White_9

Operative Phrase

John-

The operative phrase was "properly designed". Not equating RFH with FHA, but FHA does not have to be poorly designed. All systems should be designed at their best.

There are enough poorly designed RFH jobs out there to give them all bad names should someone take those poor performers and call them indicative of all.

Taking the worst of FHA -or any system for that matter- and saying, "see, they all do such and such horrible things", is not the responsible thing to do.

Tim_33

IF you read

what I said originally, you would know that I like radiant heat. I think it is a wonderful way to heat a space. I know how it works and I also am very familiar with its limitations. I am very familiar with forced air systems. A good portion of my income is derived from remedying the many poor practices used in the forced air systems that are very prevalent. My main complaint with you and a lot of other very competent professionals is use of negative comparisons, many of which are exaggerations of errors and not fair system comparisons, to promote a superior product. Besides that fact that your statements about forced air systems are mostly incorrect, they are unnecessary. Take the high road, not the low road. You CAN extol the virtues of hyronics and radiant heating without saying anything negative about FHA, IF you're good enough. Are you? I believe so.

Tim_33

Probably?

"..ceiling temps for FA are probably embellished.."

No probably about it. If embelishment is required, then it is a fiction.

Tim_33

John Ruhnke

Think about what you say........

Bob,

You said "is saying that marketers push the warm floors thing hard, and can leave the consumer with unrealistic expectations."

Well put, that is how I should have said it.

I now see that I should think a little bit more before I post. It is important to say it right so as not to offend.

I should have said besides warm floors there are other important benifits from radiant heating.

JR

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Kevin__Flynn

Umm, Tim...

First, "BS" was your statement from a prior post, not mine!!!

While I didn't realize we were debating English 101, I do appreciate you pointing out my spelling mistake. I might however, suggest that you consider addressing the grammar from your last post if you want to nit pick.

Now, are you capable of discussing / disputing my facts or perhaps you'd like to debate geography next?

Believe it or not, my intention WAS to be respectful.

Kevin Flynn

Tony_23

I've seen 90

at the ceiling, just not often, and not on a properly designed system.

You really want to see stacking and stratification ? Take some measurements when heat is provided by a space heater or a floor furnace

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Tim_33

My mistake...

I apologize.

Certainly love to discuss this in great detail. Don't have the time just right now.

Mike T., Swampeast MO

Into the Fray

Very interesting discussion here gentlemen even if a few parts are nothing more than petty bickering.

John has a very worthwhile contention that selling radiant floor heat because the floors are warm can be a problem. Efficient shells and/or moderate weather WILL cause a properly controlled RFH system to become "neutral" or "unnoticeable". Such can cause a serious problem with consumer expectation.

Tim makes valid arguments as well. Forced air heat is not necessarily uncomfortable.

Most of my past life and much of my current is spent with forced air heat. The most comfortable BY FAR forced air heat that I've experienced comes from a 1960s GE system with "radiant wall" registers in a rambling ranch home with 8' ceilings and at least decent returns. There are however quite noticeable balance issues. One bedroom in particular truly "sucks" air from the outdoors and the main hall return "whined" until I turned the grill upside-down.

One of my business endeavors finds me decorating homes for Christmas. These are typically in multi-gable monstrosities with "volume" ceilings and forced air heat. I will UTTERLY confirm that air temps with high ceilings are truly stifling. If the homeowner isn't around I open the doors regardless of the weather when decorating a 12' or so tree. I've NEVER seen a ceiling fan in such a space as they're too informal...

I routinely tour new homes in all price ranges under construction. While I agree with Tim that it is possible to design a good forced air system, I see utter crap conducted in the cheapest possible way. I've yet to see fully ducted returns and supplies are sized based on convenience rather than load. The joints [usually] seem to be reasonably sealed, but I've yet to see a gored elbow taped and KNOW from experience that they are inherently leak prone.

When it comes to radiant comfort my only true experience is my bathrooms. The wild, "super-simple" radiant that works off the same curve as my standing iron radiators.

My "reading room" for morning BM is located on the constantly set back side of my home. In EARLY mornings with the room temperature at 59F-61F I was not uncomfortable with my pants down reading technical literature for extended periods of time while I waited for the forced air boost in my office. This with a typical supply temperature to the Thermofin of 72F.

Christian Egli_2

>The< wind tunnel

They didn't call it a radiant tunnel either and at the time, it was the biggest in the world, right here in Dayton where the Wright brothers stole the secret from the birds.

Their success was unambiguous, anyone else in the world trying to fly planes at the time recognized why Wilbur and Orville got there first. Insert patent lawyers and you get squabbles over seemingly harmless details. That's life.

Otto Lilienthal was also investigating air lift. For his studies, he devised a whole mountain that he built in flat landscaped Berlin, off of which he jumped with his air wing tests - a testament to his drive; the mound was really big and high. That method was the precursor to the mini wind tunnel.

There, I'm making a mountain out of a mole hill. I love mentions of the Wright brothers from Dayton. They chose steam heat.

This link gets you images of the Fliegeberg, the flight mound.

http://www.lilienthal-museum.de/olma/eba1895.htm

And this one to the 1901 machine that made the pyramid obsolete.

http://www.first-to-fly.com/Adventure/Workshop/1901_wind_tunnel.htm

Sit back, relax and enjoy your flight.

John Ruhnke

I call it as I see it.....

Tim,

I call it as I see it. I believe in honesty. Honesty is hard because it isn't always what you want to hear. I was explaining why I believe radiant heating is more comfortable then forced hot air.

Yes I believe you could build a comfortable forced hot air heating system. I believe in indoor air quality. I believe that you still need to install a cooling ducted system and I believe in running a Heat recovery ventilator in the winter to keep indoor air fresh. I believe though you can run ducted equipment at a much slower rate then needed for heating so as to not stir up the air as much. I do not believe you can run a air system for heat without moving the air enough that it reduces your comfort level. I believe Radiant cooling is nice and comfortable but in this country it isn't developed far enough to be a good sole source cooling system. I believe radiant heating is more comfortable then forced hot air. Though I believe you are a very good designer and you could design a hot air system that is more comfortable then some of the poor radiant designs I have seen in my area.

I believe that a quality designed radiant heating system is the most comfortable heating system in the world.

Technology is always changing and improving. Someday I may find some system that i feel is better. I just haven't found any yet.

JR

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Unknown

and now.....

Bodies count now stand at 451... Polish officals say its true the 2 passegers did walked away from the wreckage and now asking volunteers to re insert the bodies to proper place...

Tim_33

Why the diagram is incorrect

First, we all (I think) agree that warm air is less dense than cooler air and rises in relation, right?

By your own statement, "Oh, and there is also that little rule of warmer air rising.", you must believe this.

The RFH part of the diagram shows 60 degree air (heavier) remaining suspended over 65 degree air (lighter), which remains suspended in the middle of the space, over the air near the floor at 81 degrees (lighter still). Based on your statement previously, with which I agree, this is not true.

Based on one simple principal, that (almost?) everyone agrees is universal, the comparative diagram is false. Intentional misinformation. In most people's vocabulary, this is known as a "lie". One person chose to consider this misinformation as "embelishment". So, though the diagram IS recognizable (by a proponent) as untrue, it is a "good untruth". i.e., one that helps me sell my products and services.

The details of radiation, convection (free and forced) and conduction heat transfer are beyond depiction in a simple diagram.

John Ruhnke

Have you ever measured actual temperatures at differant heights?

Tim,

Have you ever experimented and measured different temperatures at different heights?

I have been in plenty of hot air homes and noticed the higher ceiling or higher second floor temperatures. I have also seen the results of radiant systems and lower ceiling temperatures. Second floors are more evenly heated with radiant systems. The results show that with radiant heat rooms with high ceilings have cooler ceiling temperatures then rooms with hot air heat and high ceilings.

John Ruhnke

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Unknown

Tim...

Go to Boeing plane manufacting plants, I was told that the new building with RFH, workers are comfortable wearing short sleve shirt at floor while others above them are wearing jackets.... Prove what u don't know about RFH... I seen the result of 2 story bldgs, air at ceiling are cooler than floor, therefore, don't use the ceiling fans!

John Ruhnke

What I learned from an ASHRAE Technical Paper...........

Tim,

I found a study where they actually measured temperaturers all over a room with high ceilings. Here are the results.
I went to the ASHRAE bookstore and downloaded paper #3389. It cost me $6.00 dollars!! A person with a PHD was on the team.

Title: Investigation of Heating Systems for a High Ceilinged House.

17.7 foot ceiling in a room and Five methods were tested.

1) Forced air distributed from a wall mounted heat pump at about 6 ft and no radiant

2) Forced air distributed from a wall mounted heat pump at about 6 ft and radiant floor heating

3) Forced air distributed from a wall mounted heat pump at about 9 ft and no radiant

4) Floor console type heat pump

5) Radiant floor heating only

In systems 1 through 4 the temperaturers varied a lot all over the room. There were hot spots and cold spots all over the place.

In system 5 radiant only the temperatures were 86 degrees at the surface then rose steady for about a foot. At the 1 foot mark all the way up to the ceiling at 17.75 feet high the temperature was a steady 70 degrees. Also it was a steady 70 degrees from one end of the room to the other. North, south, east, west, high, low(above one foot) everything was even and steady at 70.

I think this study easily proves my point that radiant heating is much more even and much more comfortable.

In the study radiant only method 5. If you walked from one end of the room to the other you would experience 70 degrees at body height above your feet everywhere.

If you walked from one end of the room to the other with heating methods 1 to 4 the temperatures varied widly, by as much as 10 degrees. In no place, not even at the ceiling were the temperatures even. Hot and cold spots were everywhere high and low, east and west, north and south alike. I would assume that this can't be comfortable.

The study concluded in saying that with 17.75 foot ceilings they needed supplementory heat added to the radiant to acheive the temperature they were trying to acheive which was 73 degrees. The radiant only method could not get up to 73 in an 8 hour period. They also concluded that it was best to heat the room with both radiant and forced air or method 2. This of course was because they needed suplimental heat.

JR

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Tony_23

Embellishment

My statement of embellishment was in reference to the ceiling temps of FHA. I think that 95 is a bit too high, 85-90 is closer to what I've seen.

Isn't it funny how we see and read what we want to ?

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John Ruhnke

What really happens........

Tony,

Looking at the 2nd picture, the reality is that the ceiling temps in a radiant system are the same as they are everywhere else in the picture except 1 foot or less from the floor the radiant temps would be 65 chest height and 65 at the ceiling.

The movement of air described by the 1st picture is close to accurate. With forced hot air the temperatures very widly. Personally I have experienced high ceiling temperaturers and high second floor temperaturers with hot air. Though the study #3389 above, shows that the hot spots could end up any where. The hot spots will be at the heat emitters and other cold and hot spots will be throughout the room.

In hot airs defense I feel that in the study they should have had more units installed and they should have run the air output at a slower speed. If they did they most likely would have received better results with the circulation.

Also in radiant heats defense, I think they would have found the room heated better if they tried adding some radiant supplemental heat to the walls or ceiling. Adding forced air heat to radiant reduces the comfort margin by a lot. In method 2, Forced air distributed from a wall mounted heat pump at about 6 ft and radiant floor heating, the air temperaturer swings were just as wide as with forced air alone. In order to get good even temperaturers you really need to run radiant by itself, supplimented by more radiant heat.

JR

JR

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Tim_33

Embellishment...

is still embellishment. I want to see nothing in particular, just read what you wrote. I agree, BTW, that is embellished, slightly so, but embellished, nonetheless. So, in your opinion, is the diagram/graphic in question as accurate as possible, given your personal experience?

I realize this is nitpicking. My point is that with radiant floor heat having an obvious comfort and consistency advantage over the average forced air system, why embellish at all?

Tim_33

A wall mounted

heat pump is not quite what I would consider a good forced air system. That is not how I would design a forced air system for such a room, though without the actual layout, the ceiling height alone is not enough information to acurately describe the space. Good practice for high ceiling spaces is to provide low or floor supplies at the perimeter and high returns on an interior wall.

Any thoughts on why the electric floor panel heater differed from the radiant only floor heat? I think that you are refering to an electric resistance "mat" under the finished floor, right?

John Ruhnke

Oops a mistake!

Tim,

That is a mistake on my part. I went above and corrected it. Method 4 is a floor console heat pump. Method five is radiant heat. Method 5 is a electric floor panal heater. I think they mean electric radiant mat running at a steady 86 degrees.

JR

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Tony_23

Geez....

I didn't draw the darn thing. I'm saying the FA side is warmer at ceiling as drawn than my experience has shown. By a whopping five degrees.

The radiant side is very accurate as drawn.

I'm not condoning embellishment, merely pointing it out.

I too design very quiet, evenly distributed FA systems. I use high/low wall returns on new construction when I can get access to the HO to explain the benefits and sell them a better system if they want AC or just can't afford radiant.

I have radiant floors in my first floor of a 130 yr old farmhouse. The second floor will get radiant ceiling, mostly because of ease of installation, but also as an addition to my "showpiece" home displaying the different ways of hydronically heating a home. My fuel usage last year was about half of the previous owner's with a 90% FA. My thermostat is set at 64 and there is a wall thermometer about a foot above it that consistently reads 2 degrees cooler than the stat thermometer. Our second floor is 5-7 degrees cooler than the first floor w/o using supplemental heat.

Now tell me, you've never seen any advertising graphics embellished before ?

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