Mean, Lean, Green: An Approach to Sustainable Design
The term “sustainable development” was first defined by the Brundtland commission in 1987 as “development that meets the needs of the present without compromising the ability of future generations to meet their own needs”. Since then, we have continued to consume finite resources at an ever increasing pace. Concurrently, the negative impacts of human activity on our climate and environment has become undeniable.
In undertaking a self-build project you are committing to the consumption of considerable resources. In this context it is imperative to design with longevity and sustainability in mind. The ‘Mean, Lean, Green’ philosophy regarding resources, provides a useful hierarchy to help keep sustainable principles at the forefront of the design process.
This article will give an overview of the hierarchy and discuss ways these principles could be integrated into your home. While it is geared towards self-builders, much of the information may be applicable to home renovation projects too. Designing sustainably means minimising your use of resources where possible, which could also equate to cost savings in the long term.
The Hierarchy
Mean: Eliminate the need to consume resources
Lean: Where elimination is not possible, ensure resources are used efficiently and responsibly
Green: Use renewable resources
We will discuss how these principles could apply to three key resources: energy, materials and water.
Energy
Mean
Incorporating passive design principles, such as natural lighting, heating and ventilation and external shading , can help to minimise the amount of energy needed to operate your building. Ensuring the building is properly insulated and draught-proofed will also minimise the energy required to heat your home. This is known as a “fabric first” approach to reducing energy consumption.
Lean
Of course, some energy will still be required to light, heat and operate your home. Choosing energy efficient appliances and LED lighting can help to further minimise your energy requirement. Turning things off when not required or in use is also a simple way to reduce consumption. You may find installing automated systems helpful in keeping on top of this.
Green
There are now numerous ways to generate electricity from renewable resources domestically. However, producing all your own energy is not the only sustainable choice. By going all electric (i.e: having no gas supply) and selecting a green tariff, you can further minimise the carbon footprint of your home. With the government seeking to de-carbonise the grid, even those on a conventional tariffs may see the carbon-footprint of their home energy use decrease in the future.
An example of how Passive Design Principles could be implemented
Materials
Mean
The most obvious way to reduce material use is to build a smaller house! There can be an impulse to build big when designing your own home, but take the time to interrogate whether you actually need the spaces you are including. This is an area where having the benefit of a good architect can be really useful, to help you refine your brief and make the most out of spaces. There is a direct link between the size of your house and how much it will cost to build, so designing smaller will also inevitably save you money too.
However, keep in mind that part of sustainable development is ensuring future generations are able to meet their needs. If your home is too bespoke it may be unsuited to other households in the future, which could lead to wasteful demolition.
Another way to reduce material use in the long term is to select durable, high quality and repairable materials. These materials will have a longer lifetime, meaning replacement will be required less frequently. Of course, this does come with a cost. If necessary prioritise spaces and items that are likely to receive the most wear.
Lean
A lean approach to materials means minimising waste. Considering which materials you intend to use early in the design process can help here. Many construction materials, such as brick and plasterboard, come in standard sizes. Designing with these dimensions in mind will minimise off-cuts and waste on site.
Another crucial step to a lean approach is to maintain your building properly once in use. Caring for your building will extend the life of all the materials and systems used in its construction, minimising waste in the long term.
Green
With materials such as glass and concrete integral to construction, it will not be possible for your home to be constructed from entirely renewable resources. Other materials however, such as timber, are almost infinitely renewable. Insulation is another area where many natural, renewable options are available. Consider where the use of renewable materials may be possible, balancing this with performance and longevity when making your selection.
Water
A natural swimming pool also provides valuable wildlife habitats
Mean
Reducing the demand for water in your home will primarily come down to the appliances and fixtures you select. Selecting water efficient taps, toilets, showers, washing machines and dishwashers will all contribute significantly to minimising your water demand. For example a typical power shower uses 12 litres of water per minute. However, it is possible to specify showers that use half this amount. There are even products available that emulate the experience of a power shower without increasing water use.
You can also introduce design measures to reduce water use during the construction of your home, such as minimising the need for wet trades or dust suppression. However, the average person in the UK uses approximately 149 litres per day. Therefore taking steps to reduce your overall water consumption is likely to have a greater overall impact.
Lean
Designing a compact water system can help improve efficiency as shorter lengths of pipe work mean less heat is lost when distributing hot water. It also means hot water will arrive at the outlet quicker. Consequently water is left running for a shorter period of time, conserving water. A compact water system can be achieved by grouping WCs, bathrooms, kitchens and utility spaces together either vertically or horizontally.
There are of course also many habits that can help to reduce your water consumption. These range from the obvious, such a switching the tap off while you brush your teeth, to the less intuitive. For example, did you know that a fully loaded dishwasher consumes less water than cleaning the equivalent volume of dishes by hand?
Green
Considering water covers 71% of the planet, it can be difficult to perceive that it is a finite resource. However, only around 0.0033% is suitable for human use; with 97% being saltwater and the rest trapped in glaciers or deep below ground. In the UK, the mains water supply is fresh, drinking water. The treatment of water to make it suitable for drinking requires a significant amount of energy and there are many uses within the home for which this quality of water is not necessary.
Rainwater can be used to flush toilets, supply washing machines, water plants and clean vehicles. However a dual pipe system may be required. As a minimum, rainwater harvesting should be used for gardening purposes.
Future Proofing
Our climate is now rapidly changing due to human activity. While the ‘mean, lean, green’ philosophy could help you to minimise your carbon footprint, it is inevitable that our environment will continue to change for some time. To ensure your home has a long life and continues to be habitable, you must consider the changing climate within your design. In the UK, it is likely to become hotter and wetter. This means you should design your home and landscaping in a manner that eliminates the potential for overheating and mitigates any flood risk.
Final Word
Compact, high quality homes are likely to be the lowest impact, minimising the use of resources. However, homes should be designed to have some flexibility so that they can be adapted the needs of future generations. Ultimately, your building isn’t sustainable and efficient if it has to be demolished in 50 years. Future proofing your home and using repairable materials and systems will go a long way to extending the lifetime of your home. Given the vast amount of resources that go into construction, longevity and sustainability are often intertwined.