Zero carbon homes: what you need to know

Learn the difference between the embodied and operational energy of your self-build or extension with this quick guide. 

By Hugh Metcalf | 14 July 2020

Learn the difference between the embodied and operational energy of your self-build or extension with this quick guide.

studio anyo gs8 carbon positive development - grand designs - self build

Image: Orford Mews, a pioneering development scheme by gs8 and Studio Anyo, approved for construction in Walthamstow, East London, is carbon and energy positive, using a zero waste framework.

For the eco-conscious among us, the idea of a zero carbon home may sound very enticing – however, what exactly that means is a different story. We may be familiar with ideas of sustainable energy sources and sourcing of materials, but you may find yourself up against some

What does zero carbon mean?

Zero carbon refers to both embodied energy and operational energy. Embodied energy refers to the energy which is used in the manufacture of the building materials, while operational energy is that which is used to heat, cool and power your home.

The embodied energy of insulation, for example, is the energy which is used to create the insulation itself, while good insulation will help towards lowering your home’s operational energy.

Watch now: Grand Designs Live from Home – Zero Carbon Homes

How can I lower my build’s embodied energy?

Concrete is still the industry standard for foundations but it has high embodied energy. You can reduce the embodied CO2 of foundations through different cement mixes or use of limecrete, but not offset it completely.

“One of our new timber-frame houses is set on a compacted gravel trench foundation, using aggregate from the previous demolished house with mechanically compacted layers, topped with limecrete to bind it all together,” Adam Knibb of Adam Knibb Architects offers as an example”You can also build using timber frame construction method, which has low embodied energy; all buildings ideally need to be constructed this way to minimise the environmental damage.”

Modern solutions such as SIPs (structural insulated panels) and CLT (cross-laminated timber) are best for reducing the carbon footprint. Cob or straw bale could be used but it’s important to think holistically about the building as they don’t lend themselves to airtightness so additional membranes to reduce leakage will be needed.

The amount of embodied carbon can be broken down into almost all component parts – from insulation to windows and doors to your interior choices.