Overview of proposed research:

 

There are many ways of improving a home’s energy efficiency, be it more efficient heating systems, renewable energy sources, or by simply increasing how well it retains its heat. By simply adding additional insulation to the outside of an exterior wall, the R value of that wall will increase, lowering heating costs and improving the overall building envelope. To calculate how much energy is being saved, heat loss calculations will be performed on each of the wall types mentioned in the first post. Because replacing the type of wall system in the existing house is next to impossible, adding insulation to the existing wall is the only viable alternative. Calculations will be done to see how long it will take to offset the cost of adding extra insulation to the house with the cost savings of the heating system.

Most single family homes in North America have a standard 2X6 stud construction which uses Batt insulation between the studs to insulate the walls. This method of building is very inefficient in its construction, heat retention properties, as well as air tightness. Over time the Batt insulation slumps because of gravity, creating large thermal gaps near the top of the wall, where air temperature is the highest inside a building. The studs themselves also create a thermal bridge where heat radiates out of a building more quickly, as shown below:

image source:(http://hubpages.com/hub/Bioclimatic-Architecture-Concepts, Thermal Bridges & Heat Loss)

By installing ridgid insulation to the outside of the sheathing, the wall will have little to no thermal bridges or gaps, depending on the thickness of the insulation. Air permeability may also be increased if the joints of the ridgid insulation are taped off. The heating system in the residence will be used less because the house will take longer to cool down, effectively reducing energy consumption.