Building fabric performance

As I mentioned about heat on (Climate Change) post. Thermal bridging could also affect on the heat loss of a building. In term of zero carbon home, good practice on fabric energy efficiency could solve the problem of overheating. Wall, roof, floor, window or door in a dwelling can minimizing the heat loss. For building form, a building’s shape will also affect the internal temperature and heat loss. The smaller surface are of a dwelling, the less heat escape, but it could also affect natural ventilation. Below diagram shows the percentage of fabric heat loss, bridge and ventilation. 

U-Value:
The U-Value is for measuring the amount of energy. When the U-Value is lower, it means the materials could preventing the heat loss better, or vise versa. Below is the method of calculating the U-value.

In my example of Oxley, the walls of the U-Value is U= 0.12W/m2K. As the dwelling of Oxley Wood is made of timber panels, it provides a better thermal efficient to lessen the heat loss. The timber panels of Oxley Wood are filled with Warmcel cellulose fibre insulation. It can decrease the construction cost as they are made of recycle materials, and providing better performance value (Photo A). The U-Value of the roof in a dwelling of Oxley Wood is U=0.17 E/m2K. As the timber panels are covered with rigid polyurethane (Photo B) board, it has lower thermal conductivity and higher thermal resistance. Also it could solved the problem of the timber getting rod in a period of time. As the windows of Oxley Woods are using double glazed window, the U-Value is U= 1.7W/m2K. 

(Photo A)

(Photo B)

In terms of heat loss, as I mentioned of Ecohat, the feature helps to reduce the energy consumption. The system can also help to prevent the timber frame rod due to the occurs of condensation by the change of heating, ventilation and unforeseen reasons. 

Sources:

BING. (2006). Thermal insulation materials made of rigid polyurethane foam (PUR/PIR). Available: http://www.excellence-in-insulation.eu/site/fileadmin/user_upload/PDF/Thermal_insulation_materials_made_of_rigid_polyurethane_foam.pdf. Last accessed 15th Nov 2013.

CMS. (2011). Warmcel Cellulose Fiber Insulation. Available: http://cms.esi.info/Media/documents/20909_1320849921647.pdf. Last accessed 15th Nov 2013.

RIBA. (2009). Principles of Low Carbon Design and Refurbishment. Available: http://www.architecture.com/Files/RIBAHoldings/PolicyAndInternationalRelations/Policy/Environment/2Principles_LC_Design_Refurb.pdf. Last accessed 15th Nov 2013.