PRiSM housing configurator app: the shortage of houses is a global problem

Taking a 200 m2 house, (10 m x 10 m x 2 storeys, 40 % WWR) as an example, Bryden Wood has done a rough estimation of the impact that Passivhaus distinctive strategies have on embodied carbon:.

In order to substantially reduce operational carbon, our designs will adopt the following hierarchy:.Be Lean (passive): minimise the use of energy via passive design measures such as optimised form, orientation and window-to-wall ratio (WWR); design energy efficient facades that incorporate thermal insulation, high airtightness, external shading and solar control glazing; use of natural ventilation and thermal mass and design transitional spaces and low thermal expectation spaces.. Be Lean (active): minimise the use of energy via energy efficient lighting (LED, daylight and presence control sensors) and ventilation systems (demand control ventilation, low SFPs, heat recovery); use technologies such as waste-water heat recovery and specify energy efficient lifts and appliances/equipment.. Be Clean: connect to district heating networks that have plans for decarbonisation; explore plans and feasibility of local hydrogen district networks.. Be Green: use onsite low and zero carbon technologies such as air source heat pumps (ASHP), ground source heat pumps (GSHP), photovoltaic panels, solar collectors for domestic hot water and wind generation among others.. Be Smart: implement innovative technologies such as electric batteries, heat storage, post-occupancy evaluation and develop smart-metering systems..

Offset: any remaining carbon should be offset via Power Purchase Agreements (PPA) or recognised carbon offset schemes.Offsets used should be publicly disclosed.. An example of specific design strategies that Bryden Wood have adopted follow the proposed operational carbon hierarchy is shown in Figure 5 and is demonstrated with examples below..Step-by-step hierarchy for net zero operational carbon.

In order to substantially reduce embodied carbon, our designs will adopt the following hierarchy:.Build Nothing: identify opportunities to reuse existing structures, refurbish and reuse demolition materials onsite.

Build Less: optimise the building’s form, structure, structural grid, WWR and DfMA components; recommend the use of durable materials, design-out basements and false ceilings (exposed soffit); design spaces which are adaptable and can be easily deconstructed..

Build Clever: specify low carbon materials with a focus on the recycled content of steel and concrete and the use of timber; maximise the recycled content of finishes, use reclaimed floors and explore system’s rental; where possible use low GWP refrigerants and avoid VRF systems..COVID-19 facilitated that to a certain extent, with companies forced to transition to digital very quickly and managing to do so successfully.

However, while every other sector has experienced disruption to their business model creating major changes, construction is very risk averse and the implications are long-term.To get a digital thing slightly wrong has, in a sense, a transience that doesn’t matter.

However, there are bigger implications for not building a building correctly..In terms of where the construction industry is heading in the near future, Professor Glass says that in addition to prioritising our climate change issues, she’d like to see an end to the use of Return on Capital Employed for all of the major contractors.