Insulation and energy use

Extending the thermal insulating qualities of homes to their limits

"Even in a temperate climate such as the UK, energy for space heating in the colder months accounts for over half of total domestic delivered energy. This could be reduced if homes were better designed and constructed to retain heat." [Atkinson, 2008, pg. 30]

With a threat of peak oil and global warming in mind, since 6 April 2006 UK government introduced amendments to existing Building Regulations, in order to improve energy efficiency in buildings. The standard requirements for insulation were increased to twice that of the previous requirements. The following table shows how the insulation values of an amazonails standard build* complies with the new Building Regulations (lower the value better the insulation):

Specifications determining houses without any need for heating or cooling take the requirements for the building insulation much further:

• The Association of Environment Conscious Builders (AECB) silver standard specifies measures leading to overall 70% reduction of CO2 emissions compared to the UK average for buildings of each type.
• The AECB golden standard aims at reducing overall CO2 emissions by 95% and is almost identical with passive house standard, that describes the buildings insulated to such a level that they could be heated by mere presence of people without any internal source of heat.
• BRE Zero Heating House Standard defines a similar goal.

Following table shows how the insulating values of different specifications comply with insulating values of amazonails standard build*.

* The values were researched and calculated with thermal bridging in mind, making the figure as realistic as possible [Atkinson, 2008]. amazonails standard roof incorporates a 300mm layer of insulation ,the floor 200-300mm (depending on floor type). The table shows clearly that in order to comply with other zero energy standards ,an amazonails standard build would simply need to increase the level of insulation in the floor and roof, and use triple glazed windows.

In terms of insulation, an amazonails standard build is comparable with standards describing houses requiring no heat in the winter and no cooling in the summer. However, high insulation values of single construction elements within the building do not necessarily mean that the whole building is insulated. Civil engineering practice struggles to employ modern building technology - creating seamless joints between construction elements, in order to achieve the heat loss due to air infiltration comparable with value described as AECB silver standard.

An air tightness test in accordance with BS EN 13829:2001 was carried out on an amazonails standard build.

The extremely low values of air infiltration is in strawbale buildings achieved by extreme attention to the smallest detail and perfectly executed, high quality plaster wokrs. We can teach you how to do that.

The following table shows comparisons of its results with UK Building Regulations and AECB silver standard (lower the value more airtight the building is) [Atkinson, 2008]