Insulation Options with Ultra Fin

Heatmeister_2

In other words Ultra Fin says " 3 inch above an 2-3" below, for a total of 6" plenum. My joists are 10" so the method you suggest might be perfect, but time consuming.

Next question and important, how did you suspend your tube? My guy did it with cross bars. Some are higher than others....and this concerns me. I spoke with UF last week. They recommend the snake hanger. That way you know that you are exactly 3 inches down.

Heatmeister_2

Insulation Options with Ultra Fin

I am ready to put up insulation under my Ultra Fin. However, I cannot get a staightforward answer on what type of insulation works best. My basement is heated with PEX ins slab, so I am trying to find out performances differences between the following:

1)Insulation with no Batt, 2)Insulation with Foil Batt, 3)Insulation with regular Batt or 4)Bubble with Foil.

My intuition leads me to believe that Foil Batt (foil side facing Ultra Fin Plates) would give you the best "responsiveness" and possibly best efficiency. However I have no emperical or anectdotal evidence. Ultra Fin does not specify insulation type and in the marketing material they just show plain insulation with no Batting material under the floor.

A real easy install, given this remodel, would be to buy 4 foot wide rolls of foil and lay them across the bottoms of the floor joist and rock right over. I could do my whole basement in a few hours. However this would heat the entire joist cavity up, thus reducing responsiveness. Ultra Fin did not have much data on this, but did say as long as my basement is heated, this would work as well as batt. My intuition again leads me to believe this is not true.

Anyone care to weigh in? I could some real life examples.

Thanks

Unknown

I recommend insulating with a real aluminum plate.

Har har.. seriously, I would put in at least an R13 over heated space; batt, or foam. If you want reflectivity, it'll help.. at least at first.. but is NOT a replacement for real R-value in my opinion. Longer term effectiveness is too iffy.

Make sure the rim joists and edge joists are well sealed as well.

Bob R

ultra-fin

From what I remember from the Ultra-Fin class is that this is not a quick response system. The idea is to heat up the joist space and the heat stays contained and radiates through the structure. I think they said standard batt insulation with no facing was the best.
Bob

Heatmeister_2

Can I enhance the system with Foil...

You're 100% correct. Heating up the plenum space is how the system is designed to work. However, I "thought" I could enhance the system by using foil faced batt with foil facing upward. I was thinking that doing so would help contain the heat in the plenum space, about 5 or inches, rather then allowing some of the heat to work its way down further into the entire joist space. Does that make sense, or is it the case that once the space is heated, it's a mute point?

I am no expert, but intuitively, that makes sense to me. Any insulation experts out there that can address this question?

Rob Blair

I have usually used foil insulation about 2 inches under the tubing and then filled in the balance with batt insulation. I know more than one person who just did as you said with the insulation at the bottom of the joist and it did well. Also I know people who did no insulation and only dry wall and it heated fine. Efficiencies, ??

Rob

kevin coppinger_4

foil will help...

a very little bit at first...but after a period on a couple on months dust will render the foil ineffective....Put as big a batt of fiberglass as will fit and call it good. Seal up the ends well..use foam if you need to. kpc

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[Deleted User]

Critical issues with suspended element radiant panels...

A consistent air gap below the heat source is a must. Push the insulation too far up into the cavity and you'll lose a major portion of the panels output.

End of bay insulation is important too because heat flows to cold.

Low resistance vaues are important over any radiant panel (thinner or none is better) cause you are already limping heat transfer wise, and you don't need any help in being bad, i.e. thick blankets of insulation being piled on top of the radiator.

A tight control on the infiltration of the building is a must.

ME

WSI Joe

R-Value is R-Value, bottom line. Like another poster said, even if you put the foil face facing up it will just be covered with dust eventually and be rendered useless as far as reflectiveness is concerned. I usually reccomend a minumum of R-19 as long as you can fit it in the bay while maintaining a consistant air gap between tubing and the bottom of the floor.

heatboy

Do you think.........

.......the insulating contractor will take the time needed to install the insulation, which is the most critcal part in this application, correctly?

I think I'll keep the extruded plate as my sole joist bay heating.

hb

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hr

My experience shows

that the foil gets dusted over and does very little work for you.

However it is easier to control the air gap with that bubble foil product that fits tightly in the joist bay and has a staple tab.

If cost isn't an object use a layer of bubble under the 2" air space, then a fiberglass batt. Not compressed!!

Did you do a heat load calc first? I'm not convinced you would get the same output as a plate sysyem. Under 25 btu/ ft should be fine.

I've found UF to be a big step up from the dangaled (aka suspended tube) method. You need to work within their limitations.

I did some testing comparing foil/ bubble/ foil compared to an R-11 batt recently. Actually the thin bubble foil, alone performed as well as the R-11. This was under a plate system demo in my shop. Neater looking and the itch factor goes away.

hot rod

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Ken_40

Keep in mind however,

The refective value is not lost due to dust, merely minimally occluded. Remember, the reflection of radiant energy is NOT what one sees, rather, what actually happens.

A few thousandths of an inch of dust is a minor factor, when coimpared to the absolute heat-sink nature of open FG batting. One does not insulate against radiant energy as well as one can reflect it. We CAN insulate against the heat, but must remember the heat is the result of radiant energy striking an absorbing material.

Heat is a function of air. It can be the result of radiant energy, but not the cause, unless of course the radiant is a log fire, an oil flame, or the face of the sun.

Then too, it could be the warm water, half an inch below the oak flooring...

Plumdog_2

No empirical or anectdotal

but I tried this and it works: 2 inch rigid insul board cut in widths to fit tight between the joists; it will squeeze enough to stay put. Whether or not it should have foil facing is arguable, but I don't think it can hurt, even it does get dusty eventually. You can find damaged stocks of this stuff at the lumber places cheap. It is messy to cut but really increases the amount of heat driven upwards to the floor. Just install it flush to the joist bottoms and leave a cavity above. Batts are not tight enough, and bubble foil is for wrapping presents only.

Ken_40

I agree!

Being fanatical, I also placed a bead of 3X foam on the jont where the 2" foam and joist web butt. I did simple FG with 2" air void in another area. Surface temps are 3 degrees higher in the reflective foam area. It's been almost a year, and a wire needed to be run and a ceiling opened. The foil face is still pristine.

Admittedly, the house is not just tight. It is super tight. About two A.C.s per day! That may explain the foil face cleanliness, but not the 3 degree better temperature surface readings

[Deleted User]

R you kidding me???

HR, DId you adjust for the emmisivity of bright aluminum with your IR camera when you shot the B/F/B??

My testing of it proved that it had the equivilant R value of 1/2" sheet rock. R=.5...

Inquiring minds...

ME

Glenn Sossin_2

Foil like a mirror ??

While I don't know this to be factual, I would think the value of the foil as a reflector of heat energy would be just like a mirror reflecting light energy. A dirty coated mirror will not reflect light energy as well.

I remember reading about foil chips blown into attics as an insulator for AC systems in the Southwest. The reason for the layers was to preserve the lower layers refelctive characterists by keeping it clean and letting any dust particles accumulate on the top layer.

HR, i'm sure you could prove or disprove this easy enough with some IR photos. Love to see and confirm that is the case.

hr

Hard to read a surface that shines!

I tried all the scales on the camers without a good read. Same with the fiberglass batts.

Later in the day we sprayed the bubble and fiberglass with flat black paint.

I need to dig out that pic, as you can see by the scale this was not it.

I will say to the touch the bubble foil never got warm on the bottom side, even with 120F running to the plates for over an hour. Hard to get a feel on fiberglass batts
I know that faced bubble foil does a great job doing what it was designed to do.

Many poultry barns around here use it under the rafters to reflect heat. It makes a big difference in temperatures.

I notice they are making roof plywood with aluminum on one side.

Hmmm must be a radiant application there.

hot rod



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Unknown

In dusty conditions, oak ridge measured a 50% reduction in effectiveness in one year.

That's in conditions worse than a typical joist bay, perhaps, but still does not bode wall as far as I'm concerned.

Ken_40

Visible wave

Or radiant?

I have no idea, but being an amateur astronomer I would be hard pressed to "see" a distant star with 1/100th of an inch of dust on the reflector mirror - suggesting 50% of what could be seen - is now lost.

But I doubt it would reduce my radiant energy more than 5% - if that much.

The fundamental reasoning being, 100% visible waves are blocked by anything opaque; while radiant energy passes THROUGH objects, diminishing in power similarly to light, but far less so.

What we feel, and what we see are totally different phenomenon.

If I heat a pot bottom with radiant energy, doesn't the heat pass through to the food being cooked?

But if I put a light under the pot - it CANNOT pass through the pot botom.

Or did I miss something?

Unknown

thermal effectiveness, not visible transmissance.

http://www.ornl.gov/sci/roofs+walls/radiant/rb_02.html

It's not definitive, but it does indicate that trusting reflectivity long term may not be particularly well advised in a typical radiant (upward facing) application.

Where are you getting the idea that radiant energy passes through opaque objects? Last I knew, when radiant strikes an object, the object heats up, indicating the energy is being absorbed, not passed through. And until said object heats up and re-radiates through the other side. You don't heat food in a pot by allowing radiant energy to pass through, you radiate to the pot which heats up and then conducts or re-radiates out of the other side of the pot surface.

Radiant energy IS infrared light. It's just a light we cannot see.

Heatmeister_2

I am still confused

In other words, if I use the foil batt below my floor, AND it gets dirty, its value diminishes over time, thus loosing the effectivenes of the product. Not too mention it costs 3X's as much as unfaced AND takes 2 weeks to get in my area b/c nobody carries it.

But what if the foil doesn't get dirty? My rims are all foamed and their will be drywall underneath (my ceiling).

jp_2

not simple at all.....

very interesting topic.

simple answer, it depends.

x-rays partially past through us, so I assume by varing the frequency of the x-ray less or more will past through, until all or no x-rays pass.

ever cover the flash light with your hand at night? body seems to past a fair amount of light.

ever wonder 'what makes glass transparent? 3 years at university and I could not asnwer this, neither could several within the physics dept.

so, what is transparent to what wavelenght/energies is a real complex question

hr

If you look closely at foil faced batts

you will notice about 1/4 or more is printed on with red ink. R-value, brand name various listings, etc. So that part isn't available to "mirror".

If it were me and I REEEALY wanted an aluminum faced batt I would (and have) purchased un-faced batts and wrapped restaurant gauge aluminum foil on top.

100% shiney surface, heavier gauge, and a lot cheaper than special order foil faced fiberglass batts. Not much foil faced stuff on the shelves these days.

hot rod

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hr

Take a look at this Ultra Fin under power

I took this shot about 15 minutes after start up. Again, I had to spray paint the UF to get a good read. All I had with me was some bright red marker paint

Fair enough to say the addition of UF greatly increases the emitter surface conpared to plain "dangled tube" methods, when talking joist bay convection systems.

Also notice the "pigtail" tube supports.

hot rod

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Jed_2

Hot Rod

Please tell me; what's the 95.6°F temp? Air? Yes, those "Snake Hangers" allow parallel tube installation. It get's a little complicated trying to figure the "adjusted" UF spacing and drill sequence. Or, just wing it?

Jed

Unknown

good points jp.

In practical terms though, opaque is "opaque enough" to block radiant heat transferance here in the real world. You won't get enough through to make any difference to anything, at least.

Here's how glass works, btw.. defintely more complex than my example was! http://science.howstuffworks.com/question404.htm

hr

95.6

is the temperature of the fin near the tube. The air tempersature in the bay was around 65F. Supply from the Knight at 110F.

I suspect what you see is the temperature change @85F as the air passes through the fin, purple color.

I used the UF design program to get the count and spacing of the fin installation.

Old habits die hard, I used two tubes per joist bay and staggered the UF's. It took less drilling, but used more tube.

Also gave me a bit of a cushion, seeing as I was trying to meet the load at the lowest possible temperature to keep the mod con pleased.

Second heating season, the Knight is on reset with 150F max. supply. I doubt it goes that high very often.

I don't agree you MUST run 160- 180 to get UF performance.

As always the loads will determine the required temperatures.


The beauty of that Lochinvar Knight is the adjustable boost feature on the reset program. It will boost until it get's the job done.

All in all I was very pleased with the UF system in general. In the tall ceiling, glass ended great room I did add some ThermoFins on the exterior wall sections. Just to be sure as it was all sheetrocked below, no second chances:)

Somewhere I have IR pic of the floor above with the UF at work.

hot rod

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Singh_6

Can someone

explain to me when is a radiant floor panel , well ,radiant.

My understanding is that the foil stuff can reflect 97% of radiant energy. Or at least that's the claim.
But I thought the systems most of us install are primarily conductive forms of heat transfer, tubing conducting to plates conducting directly to subfloor to toes. Or in the case of ultra fin plates conduction to air in plenum space, air to floor. The radiant part mostly does not happen until above the floor.
So what me thinks is the reflecting foil stuff is not doing much anyway.

I'm just trying to understand this foil stuff more clearly, I know it has a purpose, just not sure if it is really meant for hydronic floor heat applications.

[Deleted User]

Reading bright metallic surfaces...

Thanks HR. I've seen the same thing with shiny copper and my handheld IR themometers. The reading is real low compared to actual. Even dulling the surface of the pipe with pipe dope helps kill the reflectiviy which affects the emmisivity.

I agree that the foil probably does reflect long wave transmssions, but as R value goes, it ain't there. Not enough dead air.

ME

Heatmeister_2

Hot Rod, I am running the same....

configuration as you have. Two tubes per joist 15" wide joist bay with 10" deep floor joists. I have each UF spaced around 3 feet or so on each tube, so that in a 15 foot run I have about 9-10 plates. Is that about what you have done or do you load up more?

When I spoke with the guy at UF directly he told me I may want to space them at 30" or less and add some addtional plates. That seems like alot to me. My runs with 1/2" PEX are about 250ft. Do you know what the point of diminishing return is with regard to plate spacing and placement? In other words, can you have too many plates which may reduce the effectiveness or does the effectiveness just taper off after a point?

Where I live in Minnesota it is cold so I want max BTU output which I believe you said is 25 BTU/sq. ft.

ALH_4

Insulation

This is a guess, but I have a feeling you are better off with extruded plates and skipping the insulation than with Ultra Fin and using insulation. You can run lower temperatures with plates, and the heat transfer is by conduction. Just a thought.

hr

Looking at the Wirsbo tables

they show a bare suspended tube output of 25 BTU/ sq. ft. at 8" spacing R-1 floor covering and 165F supply (20 degree delta T) Although they use a 65F room temperature??

Adding UF to my mind would enhance that output. I'd say 30- 36" spacing would work.

I think that 25 and up requirement speaks well to extruded transfer plates. A little more wiggle room should the load calc be off or additional floor covering added. And much lower supply temperatures.

hot rod

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Rob Blair

HR, That number sounds extremely high for tubing only. Do you really think that is true?

Rob

hr

Rob, marketing claims vsreality

is exactly what drove me to start doing all the IR filming.

It's easy to claim a method will work, and under ideal lab conditions... maybe.

But we all,know the reality of how homes get constructed, insulated, and used. A what point do you question "authority"?

Sure would be nice to have a 3rd party test and rate all these various methods. the KSU study was a good first step. better criteria and more products need to be tested and rated.

Be that as it may I know what systems do work! The conduction methods are King, no debating that.

Also knowing that 2 btu/ft/ degree difference is an acceptable radiant panel output.

With 68 room temperature and a 85 surface temperature the very highest comfortable temperature to bare feet then 85-68= 17 X 2+ 34 BTU/ sq. ft. max from a radiant floor panel.

How in the world do manufactures come up with claims of up to 50 btu/ sq. ft output? 90 degree floors or 60 degree room temperatures?Or both?

The stars may lie, but the numbers never do

hot rod

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Rob Blair

Thanks for the explanation HR. I made a copy of that one for my wall. I always forget that formula for computing the btu output of the floor.

Thanks,

Rob

Heatmeister_2

Easy to say where it not

for the fact my UF are all up and installed.

Kevin_in_Denver_2

Painting the foil

Don't forget the bubble foil reflects radiant heat UP, AND reduces radiant heat flow DOWN. By painting the bottom of the foil, HR, you reduced its R-value by almost half. That's quite significant in this configuration.