Wenatchee and Leavenworth Home Inspection-Insulation in the home

Wenatchee and Leavenworth Hom Inspection- Insulations in a home.

This is a follow up to my blog on The Scientific Basics of an Insulator.
There are many ways to insulate a home. Fiberglass is the most common but you may want to consider other options. They all have their plusses and minuses.
I am not a big fan of fiberglass for many reasons but it is the industry standard. So here is a list with some information of all the major insulators in no particular order.
The R-value for an insulator is a measure of thermal resistance used in the building and construction industry.


Insulation Comparison









Cellulose insulation (R-values- 3.0-3.7 + total fill) is made of ground-up, recycled newsprint treated with borate as a fire and pest retardant. Cellulose can be damp- or dry-blown into walls and dry-blown into attics.

 

Fiberglass insulation (2.2-4.0) has been the industry standard, is made from spun glass fibers, and is available in faced or unfaced batts or loose-fill. Precautions should be taken during installation to avoid contact with skin or inhalation of airborne glass fibers. Traditionally, formaldehyde has been used to bind these glass fibers. Formaldehyde is a volatile organic compound (VOC) that can off-gas potentially irritating or harmful chemicals into a home. Recycled-content and "no added formaldehyde" products are readily available at comparable costs. Listed by National Toxicology Program, Department of Health and Human Services as reasonably anticipated to be a human carcino­gen.

Cotton insulation (3.0-3.7) is available in faced or unfaced batts. It is manufactured from postindustrial recycled content fibers of the textile industry (primarily blue jean factories), with some polyester fiber for strength and "loft." Unlike fiberglass and mineral wool, cotton insulation is not irritating or potentially dangerous to handle. It should be torn, not cut, to fit. Cork and wool insulation are options made from rapidly renewable, natural sources and now available.

Foam board typically has a higher R-value per inch than batt and loose-fill products (e.g., expanded polystyrene, 3.8; extruded polystyrene, 5.0; polyisocyanurate, 5.8-7.0). Well-installed foam board (taped at the seams) creates an improved air barrier. Look for products that use water or pentane as the blowing or foaming agent instead of HCFC, which contributes to ozone layer destruction.







Spray-in place foams (3.9-4.3 + total fill) have excellent air-sealing properties, high R-values, and most of them can easily be installed anywhere, including overhead. They are a particularly effective choice for "cathedralized" attics (insulation is installed at the rafters, so the attic is within the thermal envelope. This is a good approach if ductwork is placed in the attic). Most of these foams are low-density, open-cell polyurethane or polyicynene. HCFC-free foam is available, as is soy-based foam. Spray foams are newer in the market, so installers may be hard to find and costs may be high.













Mineral wool (2.8-3.7) is produced as batts or loose-fill made from rock wool (from natural rock) or slag wool (an iron ore blast furnace waste product).











Structural insulated panels (SIPs) (4.0 + total fill) consist of rigid expanded polystyrene foam sandwiched between panels of oriented strand board (OSB). SIPs are fabricated off-site, come in thicknesses from 4 to 12 inches, and are fairly interchangeable with wood frame construction if incorporated early in a project's design phase. SIPs advantages include a very high effective Rvalue, excellent soundproofing performance, and rapid on-site installation. Note that mechanical ventilation is typically required when using SIPs due to the resulting airtight nature of such construction. As with foam board and spray foams, look for products fabricated with and from more environmentally friendly foam materials.





Radiant Barrier-(little or no R-value) Radiant barrier insulation systems reflect radiant heat energy instead of trying to absorb it. Radiant barriers come in a variety of forms, including reflective foil, reflective metal roof shingles, reflective laminated roof sheathing, and even reflective chips, which can be applied over loose-fill insulation. The reflective material, usually aluminum, is applied to one or both sides of a number of substrate materials. Substrate materials include kraft paper, plastic films, cardboard, oriented strand board, and air infiltration barrier material. Some products are fiber-reinforced to increase the durability and ease of handling.

Radiant barriers-which don't provide a significant amount of thermal insulation-can be combined with many types of insulation materials. These combinations are called reflective insulation systems. In these combinations, radiant barriers can also act as the insulation's facing material.

Recycled Content (environmental comparisons)

Insulation materials vary in their recycled content.  Which insulation offers the environmental benefits of resource conservation and reduced waste? The typical recycled content of various insulations is as follows:

Fiberglass: 0-30%, mostly post-industrial, some post-consumer

Cellulose: 75-95%, mostly newspapers

Mineral wool: 0-90%, rock wool - 0%, slag - 90%

Cotton: 75-95%, post-industrial fabric trimmings

Foam board: 0-50%, post-industrial foam

Spray foam: 0-15%, post-industrial chemicals

Radiant Barriers: 0-100%, mostly recycled aluminum

Wenatchee and Leavenworth Hom Inspection- Insulations in a home.

NCW Home Inspections, LLC  is located in Wenatchee Washington serving Chelan County, Douglas County, Kittitas County, Okanogan County and Grant County Washington and the cities of Wenatchee, Leavenworth, Cashmere, Orville, Cle Elum, East Wenatchee, Quincy and many more...                           

NCW Home Inspections LLC-509-670-9572

Wenatchee and Chelan Home Inspection- The Basics of an Insulator

Wenatchee and Chelan Home Inspection- The Basics of an Insulator

The basic principle of any insulator/insulative material is its ability to limit the transfer of heat energy.
Heat is the energy exchange between two thermodynamic systems which differ in temperature. Like the Sun to the earth or your bare body to snow. The transfer of thermal energy will always go from the system of higher temperature to the colder system. When the two systems have reached a thermodynamic equilibrium (same temperature) they will cease to exchange thermal energy.

                                                             

Heat energy moves by three basic ways: conduction, convection, and radiation. The first two mechanisms need an intervening medium to work and this is where insulation plays its major role. Insulators can be any material or means by which any or all of the three heat transfer mechanisms can be interrupted.





Conduction

Heat energy is stored in molecules as vibrations. The more the molecules vibrate the higher temperature. In some materials, it is easy for one molecule to make its neighbors start to vibrate. The neighbor molecule then makes more molecules vibrate. Before long all the molecules are vibrating (is a party!). Now the whole object has a higher temperature. This is heat conduction. Metals are very good at this as well as many liquids.






Convection

Convection is the movement of molecules within fluids (i.e. liquids, gases) and rheids (a solid material that deforms by viscous flow like lava).
For convection, warmed atoms and/or molecules which are free to move about like those in a gas or liquid circulate through the medium in a rather predictable route. It cannot take place in solids, since neither bulk current flows nor significant diffusion can take place in solids

















Radiation

In radiation is heat energy that is transmitted via electromagnetic waves. The radioactive process requires no medium. In other words, radiation (for example, light and heat) can move through empty space (like between my ears ;  ).



How Insulators Work

For conduction the best insulator is a vacuum, completely empty space. If there are no molecules, there can be no vibrations. A very good insulator is air. Gasses such as air do no transfer heat very well because the molecules are so far apart from each other.
With convection heat we want to use a poor heat conductor with as many dead air spaces we can create. Things like cellulose, fiberglass and foam board insulation work well because they interfere with the convective flow essential to that mechanism. The tiny air (or gas) filled spaces in the insulator limit heat flow because they greatly extend the time necessary for convective and conductive flow to occur.
For heat to move through these materials each cell, which there are millions, must relay the heat across it. The longer it takes, the slower the heat flow.
In the case of radiation we want heat radiation to be bounced off a substance rather than being absorbed by it. This is how a thermos bottle works or those shiny emergency heat blankets work. The shiny mirrored surface reflects heat (electromagnetic waves) back toward the source. Hot things in a thermos stay hot because heat is reflected back toward the hot contents and cool things stay cool because the heat from the outside is reflected away from the contents.

NCW Home Inspections, LLC  is located in Wenatchee Washington serving Chelan County, Douglas County, Kittitas County, Okanogan County and Grant County Washington and the cities of Wenatchee, Leavenworth, Cashmere, Orville, Cle Elum, East Wenatchee, Quincy and many more...                            
NCW Home Inspections LLC-509-670-9572