The property sector globally currently consumes more energy (34%) than the transport sector (27%) or maybe the industry sector (28%). It is also the biggest polluter, with the biggest potential for significant cuts to greenhouse gas emissions in comparison to other sectors, at no cost.
Buildings offer an easy to access and highly cost-effective ability to reach energy targets. An eco-friendly building is one that minimises energy use during design, construction, operation and demolition.
The need to reduce energy use in the operation of buildings has become commonly accepted all over the world. Changing behaviour could result in a 50% decrease in energy use by 2050.
Such savings are strongly affected by the standard of buildings. Passive buildings are ultra-low energy buildings in which the desire for mechanical cooling, heating or ventilation may be eliminated.
Modular or prefabricated green buildings, designed and constructed in factories using precision technologies, can help achieve these standards. These buildings are better quality and a lot more sustainable than buildings constructed on-site through manual labour. These are potentially doubly efficient in comparison with on-site building.
However, despite support for prefabricated house there are many of hurdles in the form of a prefab revolution.
Factory production means modular green buildings are better sealed against draughts, which in conventional buildings can account for 15-25% of winter heat loss.
And factories also have higher quality control systems, leading to improved insulation placement and energy efficiency. Good insulation cuts energy bills by up to half when compared with uninsulated buildings.
Because production inside a factory setting is on-going, as opposed to based on individual on-site projects, there exists more scope for R&D. This raises the performance of buildings, including which makes them more resilient to natural disasters.
As an example, steel structure warehouse in Japan have performed well during earthquakes, with key manufacturers reporting that none with their houses were destroyed with the 1995 Hanshin Great Earthquake, as opposed to the destruction of many site-built houses.
Buildings constructed on-site probably can’t achieve the same benefits as modular buildings. Case studies in britain show savings of 10% to 15% in building costs plus a 40% decline in transport for factory when compared with on-site production. Factories also don’t lose time as a result of bad weather and also have better waste recycling systems.
Sorting waste at Sekisui House Ltd Recycling Centre. Karen Manley
For example, Sekisui House, a Japanese builder, includes a system for all their construction sites where waste is sorted into 27 categories on-site and 80 categories within their recycling centre for the greatest value from the resources.
On-site building is ready to accept the elements. This prevents access to the precision technologies required to produce buildings on the highest environmental standards. These technologies include numerical controlled machinery, robotic assembly, building information models, rapid prototyping, assembly lines, test systems, fixing systems, lean construction and enterprise resource planning systems.
By way of example, numerical controlled machinery provides more precise machine cutting that can’t be matched by manual efforts. This, coupled with modelling, fixing and testing 98dexppky helps ensure that factories produce more airtight buildings, in comparison to on-site production, reducing energy leakage.
High-Tech Factory, Shizuoka, Sekisui House Ltd. Karen Manley, Author provided
Lower than 5% of brand new detached residential buildings in Australia are modular green buildings.
In leading countries including Sweden the rate is 84%.
In Japan, 15% of most their residential buildings are modular green buildings made in the world’s most technologically advanced factories.
Globally, there is a trend toward increased market penetration of green modular buildings. Yet their adoption from the Australian building sector is slower than expected.
Constructing houses on-site is less sustainable. Grand Canyon National Park/Flickr, CC BY
However, we can easily still get caught up. The most recent evidence implies that strengthening building codes and providing better enforcement is the most cost effective path towards more sustainable housing.
Australia doesn’t have got a great record here. Our building codes could be better focused, stricter, and certainly our enforcement might be a lot better.
Building in the future
As the biggest polluter plus a high energy user, the building sector urgently must reform for global warming mitigation.
There are serious legacy issues. Mistakes we made in the past endure throughout the life of buildings. Building decisions we make today are often very costly to reverse, and buildings work for decades! Within Australia, a timber building is likely to last a minimum of 58 years, as well as a brick building no less than 88 years.
Currently, potential building owners are funnelled toward on-site construction processes, regardless of the clearly documented great things about prefab homes. This is certainly reflected in the low profile presented to modular housing from the National Construction Code and not enough aggressive and well enforced environmental standards. We clearly need better policy to support the modular green building industry.