How to Confirm the R-Value of a Piece of Insulation?

In summary, to confirm the R-value of a piece of insulation, you can check the manufacturer's specifications or labels, which often provide the R-value directly. If not available, you can use a thermal conductivity test, measuring the material's thickness, thermal resistance, and temperature difference across it. Additionally, you can consult industry standards or guidelines that outline typical R-values for various insulation materials. Always ensure to consider the insulation's age and condition, as these factors can affect its performance.
  • #1
DuncanM
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I'm getting ready to winterize my home and was browsing the insulation aisle at Home Depot. They have a wide variety of insulating products from which to choose: soft foam, rigid foam, batts, etc.

I got thinking it might be an interesting at-home experiment to confirm the R-values of some of these products.
For example, say I bought a piece of R-5 rigid foam and a piece of R-10 rigid foam.
Is there a simple experiment I could perform at home to confirm the R-values?
Or more generally, perhaps to find the R-value of styrofoam packaging that mail-order companies use?

However, I have no idea how to go about this.

Any recommendations for how a person would calculate the R-value of insulation products (at home)?
 
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  • #3
Build a box, fill it with a known mass of ice and time how long it takes to all melt.
 
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  • #4
russ_watters said:
fill it with a known mass of ice
You could avoid some mess with dry ice.
 
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  • #5
russ_watters said:
Build a box, fill it with a known mass of ice and time how long it takes to all melt.
You would also need the temperature on the outside of the box, right?

Could be a good lab exercise!
 
  • #6
Philip Koeck said:
You would also need the temperature on the outside of the box, right?

Could be a good lab exercise!
Yep, indoors at a stable ambient temperature.
 
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  • #7
Vanadium 50 said:
You could avoid some mess with dry ice.

russ_watters said:
Yep, indoors at a stable ambient temperature.
Please, not any significant amount of dry ice in-doors.

The CO2 gas, carbon dioxide, can suffocate living creatures.

On the other hand, leafy plants will love it. :oldbiggrin:

Cheers,
Tom
 
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  • #8
Tom.G said:
Please, not any significant amount of dry ice in-doors.
I said regular ice. I'm not as concerned about the safety as you because a small amount in a closed container it will sublimate fairly slowly*, but regular ice is easier to get, handle and use for this test.

*My clients store it in pallet sized bins indoors. All of the risk happens when shoveling it from one bin to another.
 
  • #9
Tom.G said:
Please, not any significant amount of dry ice in-doors.
Dry ice expands at about 600:1 on evaporation. (As does pretty much everything) A small room is about 60000 liters. OSHA holds that above 19.5% oxygen there is no oxygen deficiency hazard (and biological effects happen below that) So even with small rooms and poor ventilation (obviously not recommended), a few liters is well within industrial limits.
 
  • #10
Vanadium 50 said:
Dry ice expands at about 600:1 on evaporation. (As does pretty much everything) A small room is about 60000 liters. OSHA holds that above 19.5% oxygen there is no oxygen deficiency hazard (and biological effects happen below that) So even with small rooms and poor ventilation (obviously not recommended), a few liters is well within industrial limits.
CO2 is not an mainly an asphyxiant, it is a toxin. The OSHA 8-hr PEL is 5,000 ppm. STEL: 30,000. IDLH: 40,000.
 
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