Quote for Radiant Heat

[93L#3008]

44x48x16 building Any thoughts here? or other recommendations. I have read most of the Radiant heat threads and still not experienced in radiant heat.

UNDERFLOOR HEATING MATERIAL
5 - 300' coils 7/8" PEX tubing (Lifetime Warranty) $1,065.00
1 - 5 Circuit 7/8" Pex manifold - 1" $519.00
1 - 7/8" Pex compression repair coupling $10.00
800 - Plastic zip ties $32.00
1 - Tubing cutter $15.00
UNDERFLOOR HEATING MATERIAL SUBTOTAL: $1,641.00
CONTROLS AND MECHANICALS
1 - SP-81 Relay box $67.00
1 - D-508 Floor/Air Control $99.00
1 - Medium/high head cast iron pump $299.00
1 - 1" Plumbing mechanical package (PMP) $369.00
1 - 2 Gallon expansion tank (TX-5 set @ 12 psi) $65.00
1 - Closed system package (1") $140.00
CONTROLS AND MECHANICALS SUBTOTAL: $1,039.00
TOTAL:

$2,680.00

 

[93L#3008]

or i can get it done for $5400?? including insulation.... im thinking let the pro's do it

 

[matouse3]

What kind of insulation?

The price difference isn't too much. Its a very time consuming task, so I guess you have to determine what kind of time you have available to learn how to do it. Its not hard, just takes time.

 

[93L#3008]

They use a foil back insulation not the 2" styro. Only use 2" around perimeter

 

[matouse3]

By "under floor" are you referring to running under the subfloor in a crawlspace?

 

[tdkkart]

They use a foil back insulation not the 2" styro. Only use 2" around perimeter

HUGE red flag right there........foil/bubble insulation ain't what it's cracked up to be.

 

[93L#3008]

HUGE red flag right there........foil/bubble insulation ain't what it's cracked up to be.

You know from experience??

 

[matouse3]

I have also read that the bubble stuff is less than adequate. Its cheap, its easy to work with, BUT with all things easy comes issues. The insulating factor is practically nothing and it doesn't perform well. I found lots of articles out there concerning this, just look around.

What is your application?- I guess I would like to know where you are building and what types of temp ranges we are looking at before I make too much judgement. How is this pipe being installed?

 

[c hardy]

Hi. I have also read many articles on the foil insulation. In North Eastern Alberta, People Do not use it unless it is layered in between the 2 sperate inches of styrofoam insulation. I chose to insulate my Pad but not heat it because of humidity concerns. My 2 cents.

Chris.

 

[BadgerBoilerMN]

Seriously 93, you read all the radiant floor threads?

There is no residential/light commercial radiant floor that requires 3/4 or "7/8" PEX tubing in this class of construction this is simply a gimmick. There have been no buildings proposed in this forum that would require or benefit from a non-barrier PEX more than 1/2" ID.

Bubble-foil is a HUGE flaming red flag. Professionals do not use or advocate its use in any radiant application, much less to insulate under a radiant slab.

Run, run away!

 

[rburke65]

The only people recommending the bubble stuff is the the people that are trying to sell it. And.....it might help if we knew where you are from.

 

[dirttracker18]

I chose to insulate my Pad but not heat it because of humidity concerns. My 2 cents.

Chris.

Care to explain that? I have in floor and no humidity issues.

 

[CARS]

Care to explain that? I have in floor and no humidity issues.

Maybe he means to control the floor from sweating???

My "old section" sweats bad on humid days, my new, insulated in-floor section is bone dry 365 days a year.

 

[dirttracker18]

Maybe he means to control the floor from sweating???

My "old section" sweats bad on humid days, my new, insulated in-floor section is bone dry 365 days a year.

He seemed to be saying that humidity issues come with in floor heating. I have never experience that with mine unless I let a vehicle melt in there. Forced air still will not take care of that.

 

[tdkkart]

You know from experience??

Fortunately I was smart enough to do my research, and in every case the actual test results echoed what the results of the link that BadgerBoiler posted above.
From what I've found, foil backed bubble insulation does OK in non-contact air to air applications, I've seen some impressive results when it's used in attics, but when sandwiched in direct contact it doesn't do much of anything.

 

[CARS]

He seemed to be saying that humidity issues come with in floor heating. I have never experience that with mine unless I let a vehicle melt in there. Forced air still will not take care of that.

No problems here.

How could a sealed system create humidity??? If nothing else, I would say that hydronic systems are DRY.

 

[Mr onetwo]

That's the craziest quote for a medium sized infloor job I have ever seen.Use 1/2" PEX laid out in 250 ft equal runs.1 manifold set (S&R)on each end of the bldg if you can't center them in the bldg.2 layers of 1 1/2" blueboard with staggered joints.Any other insulation is just a gimmick.A 60 mil vapor barrier sheet with tape on all joints and penetrations.Rebar on chairs on 12" centers with the Pex tywrapped to the rebar.6" centers for 2ft. around the perimeter and 12" there after.Insulate your tails if they get too packed together coming and going from manifolds.Use 4000 PSI concrete with water reducer and air entrainment.Spend your money on this phase of your building and you won't regret it.I have been doing this commercially since PEX first appeared in the "states".Just my humble opinion.

 

[Mr onetwo]

Another thought....don't skimp on the tubing!!!!!If your calcs call for 2200 ft use 2500, ect.More tubing means lower supply temp,more comfortable floor conditions and a more responsive system as a whole.Do not oversize your boiler under any circumstances!

 

[93L#3008]

Note that I am from Indiana so winters arent that severe normally.... Doesnt eat rise?? I asked about the insulation and he recommended 2" foam on edges but some type of radiant barrier everywhere else. hes also been doing this for years and has done his own research and recommends what was quoted.

 

[D.J.]

Indiana is a large state! Gary or Evansville? or somewhere else very big difference! Indy east west north or south?

 

[Mr onetwo]

I'm sorry Dude, but 7/8 tubing isn't used until you get up into 10,000 to 15,000 aircraft hangers and exterior snowmelt.Reflectix bubble insulation or similar has been proven to be useless underslab.I recommend 3" blueboard because it is cheap,never breaks down and pays for itself every cold day.You need to think of future fuel costs, not todays.Prices don't go down.These recommendations don't come from my "research"...they come from being involved in over 40 commercial projects from 1000 sq ft on up to over 1million sq ft.I have seen what works and what is a waste of money.If you must save money, do it on your heat source.Not on the stuff that is in concrete.You can always change out equipment, but if you screw up underslab you will be sorry for a long time.I am offering these opinions up not just for you,but others who read this.

 

[stingry]

Note that I am from Indiana so winters arent that severe normally.... Doesnt heat rise?? I asked about the insulation and he recommended 2" foam on edges but some type of radiant barrier everywhere else. hes also been doing this for years and has done his own research and recommends what was quoted.

NO! Heated air rises. The heat created by the heated water in the tubing heats the slab by conduction. The underslab insulation is necessary to keep this conducted heat from heating the ground below the slab. Once the slab is heated it then heats the space above it primarily by radiation.


Cheers
Steve

 

[BadgerBoilerMN]

I have been installing radiant floors since 1987 and can tell you, experience is no substitute for knowledge. Ask your installer for a heat load analysis. The load dictates the return on investment for insulation, condensing boilers, wood boilers, controls, tube spacing, etc. etc.

It is true that location matters, but in a flat state in the Midwest, nothing you can do with tube will matter much. Best to get a proper design, this is not the place for engineering advice.

Some suppliers will offer reasonable accuracy, but if they offer bubble foil, 7/8" PEX or
"open" hydronic systems...move on.

 

[Mr onetwo]

Note that I am from Indiana so winters arent that severe normally.... Doesnt eat rise?? I asked about the insulation and he recommended 2" foam on edges but some type of radiant barrier everywhere else. hes also been doing this for years and has done his own research and recommends what was quoted.

One of the best things about infloor is the almost complete elimination of stratification.With forced hot air,propeller unit heaters or higher temp convection(baseboard) you get a huge amount of heat up near the peak of the space...fans help a lot.With infloor, above head height there is very little temp rise.

 

[93L#3008]

One of the best things about infloor is the almost complete elimination of stratification.With forced hot air,propeller unit heaters or higher temp convection(baseboard) you get a huge amount of heat up near the peak of the space...fans help a lot.With infloor, above head height there is very little temp rise.

Thank you all for the comments... I'm a fan of saving money but also look for the long term investment.

 

[86turbodsl]

You've gotten good advice here. 1/2" barrier pex, 12" on centers, 250' loops, try to keep them all the same. 2" min 25 psi foam insulation under the whole slab. I am a mechanical engineer and have designed several hydronic heating systems. Forget the bubble insulation. If you decide not to pursue it because of cost, just spend the money on the pex and insulation so you can add it later. Trust me, it's worth it in a shop.

 

[BadgerBoilerMN]

One of the nice things about getting older is making fun of "guys who have been doing this for years. Radiant barriers often make great conductors. If what we assume is a good "radiant barrier" i.e. reflects a certain wavelength of energy, once it is buried beneath a slab and in direct contact with it, it becomes a conductor. Just the opposite of what you want.

If your radiant floor contractor has done his "research" then he won't mind referring you to his results. Where for instance did he find radiant floor radiant barriers recommended? Not in any of my dozen or so PEX manufacturers installation manuals. Can't find it in any of 5 radiant floor software programs.

It is noble and sometimes necessary to trust your local installer - to install. But go the the manufacturer or independent designer before spending serious money.

It is common for commercial buildings to be insulated at the perimeter and not at the center depend on the indoor and outdoor design temperatures, but suggesting a radiant barrier under a slab-on-grade radiant floor defies accepted radiant floor designs and common physics for that matter.

Mr. has it right. You radiate the floor to lower the warm-air stratification, increasing comfort while lowering the fuel bill.