We are facing a climate emergency.
In 2019 the UK Government passed a law which requires the UK to end its contribution to global warming by 2050, by bringing all greenhouse gas emissions to net zero. Many institutions and local authorities have committed to even more onerous targets than this. With 49% of the UK’s annual carbon emissions attributable to the built environment, as architects we must take a lead in helping to decarbonise the building industry. At Page\Park, we acknowledge that we have a responsibility to assist our clients and collaborators in decision making around carbon, and are committed to increasing our ‘climate literacy’ across the office as we take steps towards building net zero projects.
As part of this commitment, two of our senior architects Eamon McGarrigle and Jamie Hamilton recently completed the Passive House Designer course and both are now certified passive house designers. Eamon and Jamie lead the practice design and technical review process and are well placed to ensure this knowledge spreads across the office.
The Passive House or Passivhaus standard is a low energy building standard developed in Germany around 30 years ago. Its adoption in domestic settings has increased greatly in recent years as homeowners and landlords seek to reduce running costs and find ways to reduce the overall carbon footprint of new homes. The standard is not only applicable to domestic projects but can be applied to most building types. In addition, for the refurbishment and retrofit of existing buildings EnerPHit certification can be achieved. This applies similar principles to the Passivhaus certification and can result in significant energy savings being achieved in existing buildings.
The standard is voluntary, not statutory, but we believe its principles are a key step towards achieving net zero buildings by reducing operational carbon. In addition to improving energy use and running costs, the Passivhaus standard offers huge benefits for comfort and creates very stable internal environments with excellent air quality. It also acts as a quality control standard with rigorous checks throughout a project ensuring a minimal performance gap between design and construction.
The key principles of the passivhaus standard are:
Free heat in the winter from good orientation,
A simple building form,
High levels of insulation,
Extremely air-tight construction,
Minimal thermal bridges,
High performance opening windows,
Heat recovery ventilation (MVHR)
All of this aims to reduce the heating demand and overall energy use of the building. To be classed and certified as a Passivhaus building, a set of technical criteria must be met. These criteria relate to heating, energy use and airtightness with the key target being that space heating demand is less than 15kWh/m2/year. The result is a building with an extremely low energy demand and high levels of comfort.
As a comparison, a regulatory-compliant new build domestic project could have a heating demand of around 85kWh/m2/year, while a passive house project would have a heating demand of less than 15kWh/m2/year, a saving in excess of 80%. This, coupled with the other passive house principles, could result in a fuel bill of as little as £150 per year for a flat.
The path towards net zero carbon in the built environment means tackling whole life carbon. This is made up of two components: operational carbon (energy use in the running of the building) and embodied carbon (energy use in the making, maintaining and disassembly of the building). It’s widely regarded that the ‘fabric first’ approach championed by the Passivhaus standard is key to tackling operational carbon and many of the targets set for the coming years align with those achievable via Passivhaus principles.
Going forward, and in the context of fast approaching net zero targets, our projects are adopting increasingly higher standards of sustainable design and will look to actively promote the adoption of Passivhaus principles and their benefits to our clients. With recent energy crises giving a glimpse of what may become the future norm, reducing energy demand from the outset is vital and will ensure lower long term operational costs of a building and a better chance of achieving net zero.