Underslab Bubble Foil Insulation: Reflective Insulation

Radiant Heating Design Guide
 
radiant floor heat

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The performance of radiant barriers in wall and roof assemblies can not be contracted with underslab applications. 

If a distributor or manufacturer intentionally or unintentionally has lead you or anyone you know to this conclusion, contact the Federal Trade Commission

toll-free #:
1-877-(382-4357)


What does The Safety & Buildings Division, Building Products Evaluation, State of Wisconsin note for this manufacturers product?

"Limitations of approval:
Brand-X under-slab reflective insulation can be installed but, no credit will be given as under-slab insulation.

Brand X under-slab reflective insulation shall not be installed as a stand alone product in lieu of the current code requirements."


The Federal Trade Commission makes note that "Sellers had failed to disclose R-values, and caused substantial consumer injury by impeding the ability of consumers to make informed purchasing decisions."  Now if you were a consumer living in the State of Wisconsin and built your home based on the performance of the manufacturers or its distributors claim unbeknownst to you  the government  evaluation, how would you react after the home was built and you were informed that the insulation did not meet State requirements?

If you were in the process of buying or selling a home and this was brought to your attention how would you react?

Consumer Warning:

These are three landmines to avoid...

If the salesperson is...

Prescribing before diagnosing...

Masquerading marketing materials as science...

Trying to solve problems you don't have...

Call the Federal Trade Commission.

toll-free #:
1-877-(382-4357)

More is not better


Source: National Research Council of Canada

 

  

Misleading Claims on the Web...Brand-X

Example #1 : "Under-Slab Insulation the industries' number one selling under-slab insulation. Why Brand-X Works... Traditional mass insulation such as foam board addresses mainly Conduction and Convection and has been shown to be only 30% effective when dealing with Radiant heat flow. Unlike conventional insulations, Brand-X reflects up to 97% of the Radiant heat transfer back into the living areas. There is no need to use other insulating products in conjunction with Brand-X for it to achieve its superior performance... Brand-X stands alone.

Example #2: "With Brand-X under-slab installation, the response time of the heating system is quicker and more consistent due to the insulation's superior reflective properties"

HH Response: These claims appear to have come from this document.  A few other sites also state, "In a heated slab, Radiation is responsible for 93% of the heat traveling downward."  Since the claim is made under the heading of 'Under-Slab Insulation the industries' number one selling under-slab insulation. Why Brand-X Works.', a consumer could easily be misled to believe this to be true given the contents of the article when in fact downward heat loss in an underslab system is 100% conduction and radiation plays no role. 

We consider this text from the distributors web site, "In a heated slab, Radiation is responsible for 93% of the heat traveling downward", as inaccurate and misleading as is, "...underslab heating...the response time of the heating system is quicker and more consistent due to the insulation's superior reflective properties" since reflection plays no role under the slab.

Interestingly, the manufacturers website (referenced below) is somewhat careful and makes no such specific claims so you can tell in this case others are taking some liberty with information.

Example #3: "In a heated slab, Brand-X improves the performance of the radiant heating system and provides higher slab temperature output."

HH Response: The performance of the radiant panel is a function of the surface temperature, it's emissivity and the temperatures of the other surfaces in the room. No insulating product not even Brand-X is going to change the physics of radiant transfer. What insulation does in an underslab application, is slow down the conductive rate of downward heat loss, which means in part, there can be less heat input to the slab which means the design will be for a lower slab temperature not a higher slab temperature. 

In fact higher slab temperatures are not necessarily a good thing.  Most humans generally prefer surface temperatures between 74 deg F and 84 deg F with the lower value being preferable.  You can learn more about this here

We know the intent of the manufacturers wording but the general population has little understanding of heat transfer so in our opinion we consider this claim misleading. If they change the wording to state "Brand -X as an underslab insulation, has an R value Y according to test report Z by ABC Testing Agency, which reduces the conductive heat transfer to the grade below" ...it would serve them better.

Here's the real grit...In company literature an "Effective R-10" is claimed and associated to ASTM C518 test; this despite company representatives stating that they do not publish values since it changes with application. We have asked to see the original test supporting this claim but have yet to receive them.

Furthermore, at least one U.S. State has explicitly stated "Brand X under-slab reflective insulation shall not be installed as a stand alone product" when the product web site content says, "there is no need to use other insulating products in conjunction with Brand-X for it to achieve its superior performance"

This is a great big warning flag to consumers!

 Claim of the month **New**

Past Claim of the Month

Example #4 and #5

From Brand Y, "A HIGH-STRENGTH Insulating Moisture Barrier
for Use Below Heated Concrete Floors"

So here's their claim....

"Absolute Moisture Barrier
Keeps heat-robbing ground moisture away from the concrete."


Our comments:
It may prevent migration of moisture but it won't prevent heat transfer. Heat via conduction doesn't need moisture to occur - just a temperature differential...sorry brand y but that doesn't hold water in our science books (pun intended).

So here's their claim....

Reduces Downward Heat Loss By Over 50%
Exceeds the requirements of most HVAC load calculation programs.

More smoke and mirrors (pun intended again)...this is another bad case of prescription before diagnosis - first it can't reduce anything until there is something to reduce.  Two surfaces of equal temperature in contact with each other exchanger ZERO heat plus what they don't tell you is that even with the insulation the R value is still well below minimum standards such as those in the MNEC or OBC.  In our opinion, it is irresponsible to make consumers think that a reduction of 50% is better when it is grossly inadequate. Furthermore, exceeding, "...the requirements of most HVAC load calculation programs.", is a plate full of cow manure.  There is no software requirement. None. Zero. Zip. The software just crunches numbers - think MS Excel (r)  but with pretty colors.  It (the software) has no requirements to exceed - period - end of story. Let's just say these are more claims which are a bad reflection on the insulation industry (more pun intended).

This is exactly why the U.S. Federal Trade Commission and Canada's NRC/IRC are concerned about these products.

 


Have you read these statements on a vendors website?

Example #6

"Starting with the lowest level, radiant heat can be used for concrete. Without proper slab insulation, much of the radiant heat will be lost to the grade beneath. This is why it is important to use brand x under concrete bubble insulation. Not only will brand x radiant floor slab insulation provide insulation of R3.8, it also will reflect up to 97% of the heat upwards back into the living space..."

Example #7

You can increase the R value by using a radiant foil barrier such as brand x under concrete insulation. In addition to adding almost R-4 to your existing insulation brand x insulation under concrete slab reflects 57% of radiant heat back up to the surface so this heat does not escape into the ground.

HH Response: Same company - same product two different claims - both wrong and both misleading - folks you have to be very careful when shopping on line for under slab insulation.

More to come...

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