The R-Value of Insulation is a Straightforward Method For Determining the Best Thermal Resistance

The R-value of insulation is a new term for you if you are researching home or office insulation for the first time. Insulation is rated with a number that represents its ability to resist conductive heat flow. This thermal resistance is represented by an R-value. The greater the number, the greater the effectiveness. For example, insulation with an R-value of R-30 will be much better than an R-value of R-4.1.

The R-value of insulation depends on many factors such as the type of material (reflective foil, fiberglass, cellulose, etc.), the thickness of the material, its density, and how and where it is installed. Another very important factor is the climate of the region in which you live. Check with your State Energy Commission, local power company, local building materials dealer or home center to find out the optimum R-value in your region.

When increasing the thickness of insulation, R-values also increase. For example, an inch of fiberglass batting adds about 3.5 to its R-value. However, if you double the thickness of the insulation (for example, you use two layers of fiberglass batting), the R-value will increase but it will not double. If you continue to add layers of insulation, you will get to a point where the R-value is no longer increased.

There is a definition or formula to determine the R-value of insulation. The world defines R-value as kelvin square meters per watt (K·m2/W), using the International System of Units, or SI System.

In the United States, R-value of insulation is measured in degrees Fahrenheit, square feet hours per Btu (ft2·°F·h/Btu). On insulation packaging and insulation guides we see this measurement usually written as R-xx (for example, R-30).

To be really fancy, the conversion is 1 ft2·°F·h/Btu ≈ 0.1761 K·m2/W, or 1 K·m2/W ≈ 5.67446 ft2·°F·h/Btu.
But you don't need to worry about these calculations yourself, just remember that the higher the R-value of insulation, the better the insulation or resistance.

Here are some examples of R-values of typical insulation (these values are per inch):
Fiberglass Batts - R-3.1

Cellulose Loose-Fill or Wet -Spray - R-3

Rock and Slag Wool Loose-Fill - R-2.5

Open-Cell Polyurethane Spray Foam - R-3.6

Closed-Cell Polyurethane Spray Foam - R-5.5

Therma-Comfort Reflective Insulation - Heat Flow Direction UP - R-5.4, HORIZONTAL - R-6.7, DOWN - R-14.6.

As insulation sits in the cavities, walls, and joists of your home, it naturally begins to sag and age. This will cause the R-value to decrease in effectiveness. For example, loose-fill insulations will eventually settle within the cavity of your walls, reducing the air spaces. The air spaces are critical to resisting heat flow, therefore the R-value of insulation is decreased. Some foams are blown with gasses such as chlorofluorocarbons (CFC) or hydrochlorofluorocarbons (HFCs) which block heat flow and make them good insulators. But with time, the gasses are diffused and replaced with air, which drastically reduces the foam's ability to resist heat flow.

Many advancements have been made to develop products that will not settle over time and loose their R-value. For foam, you can choose closed-celled spray foam which does not settle over time and it retains its R-value. Another option is wet-spray blown-in cellulose insulation. If installed correctly, this insulation will not settle and it will last for a long time. The disadvantage of these types of insulation is the difficulty of the installation process. First of all, it is recommended that a professional install these insulations, using special machines. These machines require two people to operate them. Before you begin, it is important to carefully cover anything in the area that you don't want splattered with wet, sticky insulation. Then you have to wait at least a day for the material to dry properly before you can clean it up and finish your walls. Also, protective gear such as goggles and masks are absolutely necessary to avoid health issues.

Those are the messy, time consuming options. One of the best insulation options on the market is reflective insulation. It does not lose its R-value over time, it does not settle, and it is very easy to install. All you need is a measuring device, scissors or knife, and tape or staples. Once finished, your home, barn, office, or steel building will be insulated for as long as the building remains standing.

Therma-Comfort reflective insulation is the perfect alternative to the typical types of insulation material. It is a uniquely designed system of materials made of layers of insulating, heat sealed air bubbles encased by a 99% pure aluminum foil outer surface. This unique combination delivers a high performance insulation product suitable for all construction and home renovating. Therma-Comfort will not lose its R-value and it comes in different styles such as Foil Double Bubble Poly (FDBP) or Foil Double Bubble Foil (FDBF), and many others which all serve specific purposes. Therma-Comfort is perfect for insulating your walls, roof, attic, heating and cooling systems, garage, floor, etc. Basically, Therma-Comfort has a product for anywhere that is susceptible to heat loss or gain, which is everywhere in the house.

Here is a very important fact to remember about the R-value of insulation: R-values only measure the resistance to conductive heat flow, which is heat flow by direct contact. This is applicable when you are filling a wall cavity with loose or wet insulation because there is direct contact between the interior drywall and the exterior sheathing. But if you look at your attic and roof, for example, they are very critical in maintaining an even temperature throughout the house. Yet in your attic there is almost no conductive heat flow. All heat is absorbed through radiation from the sun through the sheathing, then through the drywall and then into your home. A radiant barrier, or reflective insulation such as Therma-Comfort, is essential to stop the heat flow that enters your home through solar radiation.

So, in some instances, the R-value of insulation, which only measures the material's resistance to conductive heat flow is unhelpful and inconsequential. But for the most part, R-value is a safe indication of the quality and effectiveness of your insulation. Also remember, the higher the R-value, usually the more expensive the cost.

If you have any questions about the R-value of insulation, please call us at (951) 675-1207. We are happy to help and we want to make the R-value system clear and easy to understand. We would especially love to explain the many benefits of Therma-Comfort reflective insulation. The R-value of reflective insulation is determined by the direction of the heat flow and we can easily explain how this information will be valuable to you as a consumer.