In all areas of our lives we’re under pressure to use less energy and do things in a more sustainable way. This includes the buildings that we live in. Since 2010 the UK government has been working towards making all new homes constructed in the country zero carbon. That means changing construction standards so that buildings become more energy efficient and the amount of energy used to run them is reduced. This has meant attention to all aspects of the construction of the building in order to ensure it meets appropriate standards.
As part of this commitment, the government has published a Code for Sustainable Homes, setting out the specifications needed to achieve zero carbon buildings. Initially, strategy focussed on more efficient heating systems, but to reach compliance with the zero carbon standard, the structure of the building must be addressed to.
This has led to a further document, the Fabric Energy Efficiency Standard (FEES), which looks at factors like solar gain, thermal mass, boiler efficiency, window area, and the U-values of the building fabric.
It’s important to note that we’re talking about the fabric – that is the structure – of buildings here, not about components made from fabric-type materials, like tensile fabric canopies from companies such as http://signaturestructures.com/.
What FEES does
The FEES approach sets a limit on the maximum amount of energy that would be needed to maintain comfortable internal temperatures in the home. This has been incorporated into the Building Regulations to set standards for different types of property. The reason for this is that flats and mid-terrace houses gain heat from adjoining properties, so they should need less energy to heat than detached, end-terrace or semi-detached houses. While the former will only need 39 kWh (kilowatt hours) per square metre per year, the latter will need 46 kWh. Measuring it in this way using Kilowatt Hours ensures that the figures are not affected by the carbon outputs from different fuel and energy types.
A key part of meeting the standard is using insulation effectively. This means not only the standards of insulation in the walls themselves but how effective the insulation is at junctions where walls and materials meet. Designers must calculate what is known as a Y-value for the heat loss of each of these junctions.