Early decisions on building form can shift the upfront carbon outcome by 20-40% before even deciding what to construct it out of. Have a look at the data we've gathered on real housing developments below.

The opportunity for impact is greatest at the start so let us help you get the most out of your project!

USE LESS - THINK COMPACT

We often talk about the importance of form factor for operational energy - but it also has a huge impact on upfront carbon too.

Upfront carbon is a term used to describe all the carbon it takes to construct a building.

BUILDING FORM FACTOR

A simple form will almost always result in:

• Less façade material
• Simpler structural solutions
• A cheaper project
• Lower heat losses
• Lower upfront carbon
  

Higher complexity = Higher carbon

• Higher complexity in detailing
• More materials & waste
• Higher installation labour costs

*Heat Loss Area = surface that is insulated (walls, floor, roof) for early-stage design this can be assumed to be the same as the building envelope.

WHY FORM FACTOR MATTERS

Even when carefully designed the walls, roof and floor can account for 60% of the upfront carbon emissions.

If we can reduce the amount of heat loss area, less materials are needed and thus less upfront carbon. Through our modelling we have found this has a much bigger impact than choice of materials.

A POWERFUL EARLY-STAGE TOOL

Early stage design choices have the biggest impact on the upfront and whole life carbon of any project, but detailed modelling is usually unmanageable at this time. Form Factor can be used as an indicator in the very early stages of design; you don't need to know every detail.

The greatest influence can be made at least cost at this stage. Form Factor can provide an early indication of the projects:

• Operational energy use
• Embodied Carbon
• Insulation requirements
• Structural demands
• Envelope efficiency

WHAT THE DATA SHOWS

Residential Upfront Carbon vs Form Factor of real projects

From the trendline: Increase in FF of 0.5 = 75 kgCO2e/m2* Upfront Carbon

Larger blocks sit above the trendline. Likely due to structure and need for lifts.

Single storey housing is consistently less efficient.

GOOD FORM: WHAT DO THEY LOOK LIKE?

Examples of efficient low-rise housing:

More examples of low-rise housing with efficient form (not WARM projects!)