The type of materials used for constructing a home can greatly affect the energy efficiency of that home. Houses can be made out of wood, brick, and even concrete blocks. Each material has both advantages and disadvantages.
Wood has always provided a plentiful and inexspensive supply for construction. It can be molded into any form desired, allowing unique designs to be made by contractors. Many houses are built from stronger woods like fir, pine, or redwood.
Brick is also used to make visually appealing and yet long lasting houses. Brick can be easily obtained and wears well. Furthermore, like wood, bricks are available in a variety of textures and colors.
Concrete Blocks are a more energy efficient building material than either wood or brick. Houses made of concrete blocks are not only stronger, but less expensive to maintain as well. The concrete blocks are usually covered with stucco to enhance the appearance of the home.
Insulation products are manufactured and sold by their R-values. An R-value is a measure of an insulation's resistance to heat flow. With today's continually rising energy costs, a well-insulated and sealed energy efficient home provides a long term return on investment through lower energy costs. Also, the reduced use of fossil fuels helps to reduce overall green house gas emissions and slow climate change.Heat is transferred in two distinct ways:
Conduction:The transfer of heat through a solid object. When an object is heated, the molecules within it begin to move faster. These molecules then hit other molecules within the object, causing heat to be transferred through the entire object. Because heat can be transferred through solid objects, most insulation usually contains tiny "pockets" of still air.
Convection:The transfer of heat through the air. In an uninsulated wall cavity, air removes heat from the interior wall then circulates to the colder exterior wall where it loses the heat. In large air spaces such as wall cavities, large amounts of heat can be lost through convection. As long as the insulation is carefully installed to completely fill the cavity, there should be no air spaces in which convective heat loss can occur.
Choosing an Insulation
There are many different types of insulation materials, each with properties that make it suitable for certain applications while being unsuitable for others.
Cellulose Fiber (Loose fill):Cellulose Fiber insulation is made from finely shredded newsprint, which is chemically treated to resist fire and fungal growth. Due to the small size of particles, cellulose can flow around obstructions to give a uniform fill. It has an average R-value of 3.6 per inch.
Glass Fiber (Batt):Glass Fiber Batts are manufactured from glass that is spun into long fibers, then woven and coated with a binding agent. They are lightweight, fit standard joist and stud spaces, and will not slump or settle. However they do not readily fit into irregular spaces and can leave gaps around obstructions such as nails, electrical wires, etc. During installation glass fiber can cause eye, skin, and respiratory irritation. The average R-value is 3.2 per inch.
Extruded Polystyrene Boardstock (Rigid):Extruded Polystyrene is a closed cell foam plastic board. Polystyrene will break down if left exposed to sunlight for prolonged periods and must also be protected from solvents. When it is used for the interior of the house, it needs to be covered with a fire resistant material, such as drywall. It has an average R-value of 4.8 per inch.