Creating the most sustainable houses possible requires us to look at their energy use from every angle. All Ecovillage homes will undergo mandatory thermal and life cycle assessments during the design phase to understand their running costs and embodied energy (total carbon emissions). This will help us demonstrate our intention that all of the homes will end up carbon-negative: they will remove more carbon from the atmosphere than they add during construction and operation.
NatHERS star rating
NatHERS (Nationwide House Energy Rating Scheme) is a star rating system (out of ten) that rates the thermal efficiency of the home’s design. In other words, how well the house can stay at a comfortable temperature throughout the year without artificial heating or cooling. We require every Ecovillage home to achieve a minimum of 7 stars, which should be easy to achieve with our super sustainable, passive solar designs.
Lot purchasers undertaking a custom design will need to engage a thermal assessor (see our Preferred Suppliers page) during the design process to do this assessment, and then provide the resulting NatHERS certificate to the Ecovillage Design Team to sign off on the design. This thermal assessment needs to be completed before the LCA as the information from NatHERS is used in the LCA.
Life Cycle Assessment study for BDGs
Life Cycle Assessment (LCA) is a methodology that quantifies the environmental impacts of a product over its life, from cradle-to-grave, to provide greater understanding and to identify areas for further improvement.
Life Cycle Logic was commissioned to conduct an LCA study to inform the development of the Sustainable Building Design Guidelines for the Witchcliffe Ecovillage. The study aimed to conduct an LCA on a base case building design, which would act as a benchmark against which a range of design options could be compared.
Read more about this in our newsletter article from October 2019 “Life Cycle Assessment of the Ecovillage”.
You can also download the full report LCA report.
Life Cycle Assessment on house designs
The life cycle assessment process is not as widely understood or used as the thermal assessments. However, it is an excellent method for measuring the environmental impact of a building by assessing “every single impact aspect of a product or process over its entire life span,” from the energy used to extract the raw materials of a building component all the way through to the energy required to recycle or dispose of it at the end of life. The LCA measures energy expended (translated into CO2 equivalent emissions), which directly impacts on global warming.
According to LCA experts eTool, life cycle design and assessment:
- ensures a genuinely sustainable and high-performance outcome for your project
- quantifies and measures your design and takes the guesswork out of sustainable building
- identifies important areas of improvement for your design
We require all Ecovillage homes to undertake an LCA assessment. We have partnered with eTool to build us a bespoke LCA software app called “eTool Turbo.” This user-friendly app will take approximately 30 minutes to enter the required information to generate a report that must be submitted to the Ecovillage Design Team as part of your house design review. The cost of this is included in the lot price.
If you’re engaging a building designer or architect to design your home, this would be a job for them, but you can certainly undertake it yourself. It’s worth noting that if you choose a design from our suite of Ecovillage House & Land Packages, the LCA and NatHERS assessments will already have been completed. eTool Turbo is still in development but will be ready for use by early September.