What Is The Best Value For The Money Exterior Rigid Isulation
Insulation keeps your home warm and can save you money. In the construction industry, how well a particular type of insulation resists the flow of heat is represented by a value called "R."
Among insulation types, rigid foam panels have the highest R-value per inch. The R-value of each insulation type varies by make and brand, and insulation with higher R-values keeps in more heat than insulation with a lower R-value.
This article collates the many different types of insulation by type and R-Value, explains what an R-value is, and also answers the question, "Can bad insulation make you sick?"
Table of Contents
- What Is the R-Value?
- Types of Insulation
- Rigid Foam or Panel Insulation
- Foamed-in-Place
- Blanket: Batts and Rolls
- Loose Fill
- Structural Materials
- Can Bad Insulation Make You Sick?
- Respiratory Irritation
- Skin Irritation
- Attracting Unwanted Pests
- Cancer
- Conclusion
- Sources
What Is the R-Value?
The "R-Value" is a dimensionless value derived to describe how well a particular material resists the flow of heat through itself. In the minority of countries still using the Imperial system of measurements, the R-Value is understood to be given per inch.
The formula for the R-Value is as follows:
Where:
- ΔT is the difference in temperature measured between the two sides of the material sample, measured in degrees Fahrenheit (℉)
- A is the area of the material measured in square feet (ft2)
- t is the time measured in hours
- q is the heat loss measured in British Thermal Units (BTU)
The units for the R-value are:
ft2∙℉∙h/BTU
Types of Insulation
There are four primary types of insulation that might be used in the construction of a residential building, each with different installation methods and different applications. The four types are rigid foam or panel, foamed in place, blanket (batts and rolls), and loose-fill.
This article also provides a fifth table with the R-Values of common structural materials for comparison..
Rigid Foam or Panel Insulation
The type of insulation with the highest R-Values, with a few exceptions, is rigid foam or panel insulation. Also called "foam board" or "continuous" insulation.
Most varieties of this type of insulation consist of expanded foam sandwiched between two rigid panels. The foam is usually expanded using a chemical propellant, most often pentane (C5H12) or some variety of chlorofluorocarbon/hydrochlorofluorocarbons (CFC/HCFC).
CFC/HCFC propellants have well-documented adverse effects on the environment. They have largely been banned or phased out around the world.
Rigid foam or panel insulation is usually installed during the construction of residential buildings, including in basements, ceilings, floors, foundations, and walls. It is typically used in interior applications but can be used in exterior applications if the panel materials provide waterproofing and UV shielding.
In addition, rigid foam offers high insulation value with minimal additional thickness. It can also block electrical short circuits as most materials are non-conductive.
| Rigid Foam Or Panel Insulation | |
| Material | R-Value (Imperial Units)(ft2∙℉∙h/BTU) |
| Vacuum Insulated Panel | 14-66 |
| Polyurethane Rigid Panel (CFC/HCFC Expanded) (Initial) | 7-8 |
| Polyurethane Rigid Panel (CFC/HCFC Expanded) (5-10 Years) | 6.25 |
| Polyurethane Rigid Panel (Pentane Expanded) (Initial) | 6.8 |
| Polyurethane Rigid Panel (Pentane Expanded) (5-10 years) | 5.5 |
| Foil-Faced polyisocyanurate rigid panel (pentane expanded) (Initial) | 6.8 |
| Foil-Faced polyisocyanurate rigid panel (pentane expanded) (5–10 years) | 5.5 |
| Foil-Faced Polyisocyanurate Rigid Panel (Initial) | 6.8 |
| Foil-Faced Polyisocyanurate Rigid Panel (5-10 years) | 5.5 |
| Urea-Formaldehyde Panels | 4-4.6 |
| Molded Expanded Polystyrene Foam (EPS) High Density | 4.2 |
| Phenolic Rigid Panel | 4-5 |
| Molded Expanded Polystyrene Foam (EPS) Low Density | 3.85 |
| Cardboard | 3-4 |
| Fiberglass Rigid Panel | 2.5 |
| Wood Panels | 2.5 |
Foamed-in-Place
Also called "spray foam," foamed in place is the newest type of insulation used in residences. It is also the best type of insulation for adding additional insulation to existing buildings.
Foamed-in-place insulation can also be installed inside existing cavities enclosed by walls, unfinished attics, and inside new walls before installing drywall or sheetrock. Before it hardens, it is essentially a liquid and can fill cavities of any shape.
Furthermore, foamed-in-place insulation is an expanding foam product applied from containers containing its base compound under pressure. When removed from the container, it expands to many times its original volume.
Like other expanding foam products, foamed-in-place insulation can stain clothes and irritate skin and is not generally fit for DIY use. Protective clothing consisting of coveralls, safety glasses, and a facemask should be worn when working with it.
| Foamed In Place | |
| Material | R-Value (Imperial Units)(ft2∙℉∙h/BTU) |
| Polyisocyanate Spray Foam | 4.3-8.3 |
| Closed-Cell Polyurethane Spray Foam | 5.5-6.5 |
| Urea Foam | 5.25 |
| Phenolic Spray Foam | 4.8-7 |
| Urea-Formaldehyde Foam | 4-4.6 |
| Home Foam | 3.9 |
| Open-Celled Polyurethane Spray Foam | 3.6 |
| Icynene Spray | 3.6 |
| Cellulose Wet Spray | 3-3.8 |
| Polyethylene Foam | 3 |
| Cementitious Foam | 2-3.9 |
| Papercrete | 2.6-3.2 |
Blanket: Batts and Rolls
Blanket insulation, often sold in units called "batts" or "rolls," is the type of insulation most often installed in unfinished walls, floors, and ceilings. Blanket insulation is generally sold in precise widths corresponding to the most common stud lengths in the country, typically four or six feet.
Due to the degree of standardization in the construction industry, blanket insulation is typically the easiest to install. Installing it is often within the ability of a typical DIY home improver.
Blanket insulation is also inexpensive and requires little labor or specialized equipment to install.
| Blanket: Batts and Rolls | |
| Material | R-Value (Imperial Units)(ft2∙℉∙h/BTU) |
| High Density Fiberglass Batts | 3.6-5 |
| Fiberglass Batts | 3.1-4.1 |
| Cotton Batts (Blue Jeans Insulation) | 3.7 |
| Sheep's Wool Batts | 3.7 |
| Rock and Slag Wool (Mineral Wool) Batts | 3-3.85 |
Loose Fill
Loose-fill insulation consists of a large amount of loosely bound or free particulates. While it can be sold in large bags, it is commonly blown in using air hoses.
Oftentimes, you may install loose-fill insulation in existing or new cavities enclosed by walls and unfinished attic floors. It can be used in new construction and retrofitting existing buildings.
| Loose Fill | |
| Material | R-Value (Imperial Units)(ft2∙℉∙h/BTU) |
| Icynene Loose/Pour Fill | 4 |
| Cellulose Loose-Fill | 3-3.8 |
| Rice Hulls | 3 |
| Rock and Slag Wool (Mineral Wool) Loose-Fill | 2.5-3.7 |
| Fiberglass Loose-Fill | 2.5-3.7 |
| Perlite Loose-Fill | 2.7 |
| Vermiculite Loose-Fill | 2.13-2.4 |
| Thinsulate Clothing Insulation | 1.6-2.9 |
| Straw Bale | 1.45 |
| Loose-Filled Wood Products (Woodchips, etc) | 1 |
| Snow (Dihydrogen monoxide) | 1 |
Structural Materials
In general structural materials like brick and wood are not intended to serve as primary insulation for residences, but they do provide some insulation.
| Structure Materials | |
| Material | R-Value (Imperial Units)(ft2∙℉∙h/BTU) |
| Most Softwood | 1.41 |
| Aerate/Cellular Concrete | 1 |
| Drywall | 0.9 |
| Most Hardwood | 0.71 |
| Brick | 0.20 |
| Glass | 0.14 |
| Poured Concrete | 0.08 |
Can Bad Insulation Make You Sick?
Old or improperly installed insulation is a common contributor to poor indoor air quality. There are four primary ways bad insulation can make you sick.
- Respiratory irritation
- Skin irritation
- Attracting unwanted pests
- Cancer risk
Respiratory Irritation
The human respiratory system is vulnerable to exposure to many different irritants, which can come from insulation. There are two primary respiratory hazards presented by insulation, propellant chemicals and loose particulate matter.
The propellant chemicals used in rigid foam and foamed-in-place insulation can be hazardous to human health. They fall under the banner of volatile organic compounds, and can be significant contributors to poor indoor air quality and "sick building syndrome."
Propellants like CFCs/HCFCs and pentane can cause headaches, airway irritation, and inflammation, and can contribute to chronic illnesses like asthma.
Old or poorly installed insulation will start to break up, releasing particles of itself into the airflow of your house. Some of these particles will eventually find their way into your lungs. This particular matter can consist of either fibers or dust particles, often too small to see.
According to the EPA, there are several potential adverse effects of inhaling particulate matter. These effects include but are not limited to reduced respiratory function, coughing from fluid buildup and airway irritation, and irregular heartbeat. Chronic inhalation can also cause long-term illnesses such as asthma and silicosis.
Skin Irritation
It must be a universal childhood experience in industrialized nations to poke your hands behind appliances. You must have also poked into holes in walls and touched something fluffy for your hands to turn bright red shortly thereafter. Those of us who have done so have first-hand experience of how some types of insulation can severely irritate human skin.
The most common culprit for this type of insulation-induced injury is fiberglass insulation. Fiberglass insulation consists of tiny glass fibers which are small enough to poke in between skin cells and can be worked rather deep into the skin.
The human immune system reacts to such an intrusion by routing immune cells to digest the invader in situ. To transport the immune cells to the affected area, the capillaries in the skin dilate to allow extra blood flow. This turns the skin bright red and puts pressure on touch-sensing neurons. That, in turn, along with the tiny fibers themselves, causes an unpleasant itching sensation.
While contact with fiberglass and similar insulation a single time is unpleasant, repeated exposure can contribute to the development of dangerous allergies. People who work with fibrous insulation should wear eye, airway, and skin protection.
Attracting Unwanted Pests
Some insulation materials can attract or promote the growth of life forms you do not want in your home.
Several types of insulation, including most made of plant matter, can serve as a growth substrate for dangerous molds. Often all mold needs to colonize a new surface is a small amount of moisture.
Spores from mold-infested insulation can cause skin irritation, watery eyes, runny nose, sinus infections, and airway inflammation. There can also be an unpleasant musty smell.
There have also been cases where animal pests have been attracted to building insulation. In the Pacific Northwest, carpenter ants have reportedly developed a taste for some brands of rigid foam insulation installed under the residential siding.
The ants seem to enjoy eating the foam and establish new nests in between the rigid panels. Carpenter ants will eventually start to eat the wood used in the structure of an infested house. They will also defend their colony by biting and stinging much larger animals.
Similarly, termites are known to be attracted to some brands of cellulose-based insulation. One particular preference is cellulose-based spray foam insulation which provides both a food source and a warm colony site.
Termites can eventually cause catastrophic damage to wood-frame structures, and their waste can release hazardous compounds as it decomposes.
Cancer
There are several ways bad insulation can contribute to the development of cancer. Volatile organic compounds used as propellants and inhaled particulate matter can damage the DNA of cells in the respiratory system, which can eventually cause lung or throat cancer.
Similarly, the microscopic fibers that break off fiberglass and similar insulation materials can cause the growth of both benign and malignant masses in the skin and other tissues. Compounds produced by various types of mold and some insect pests share this distinction.
Conclusion
In conclusion, vacuum insulated panels provide the highest R-Value of all commercially available insulation. Many other types of insulation are available to fit the needs of any homeowner. Just be careful which kind you have installed, and bad insulation can make you sick.
Sources
- Wikipedia: R-Value
- Wikipedia: Dimensionless Quantity
- Wikipedia: Pentane
- Wikipedia: Rigid Panel
- Wikipedia: Silica Aerogel
- Wikipedia: Vacuum Insulated Panel
- Wikipedia: Silicosis
- US Department of Energy: Insulation
- US Department of Energy: Type of Insulation
- US Department of Energy: Insulation Materials
- United States Environmental Protection Agency: Volatile Organic Compounds' Impact on Indoor Air Quality
- United States Environmental Protection Agency: Introduction to Indoor Air Quality
- United States Environmental Protection Agency: Indoor Air Facts No. 4 (revised)
Sick Building Syndrome
- United States Environmental Protection Agency: Health and Environmental Effects of Particulate Matter (PM)
- Great Day Improvements, LLC: Insulation R Value Chart
- Energy Education: Calculating R-Value
- Steinhoff Building: Typical per-unit-thickness R-values for material
- Merriam-Webster Dictionary: Batt
- Great Northern Insulation: Bad Insulation Can Actually Make You Sick!
- Insulation Building Materials: Addressing Skin Irritation and Other Health Risks of Pink Fiberglass Insulation
- Green Building Advisor: If Ants Like Rigid Foam, Should We Stop Using It?
- BEC Green: Carpenter Ants and a new nesting source: Rigid Foamboard Insulation
- West Roof Systems: Spray Foam And Termites: What You Need To Know
What Is The Best Value For The Money Exterior Rigid Isulation
Source: https://www.attainablehome.com/what-insulation-has-the-highest-r-value-per-inch-with-table/
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