Thursday, 19 May 2011

The Principles of Sustainable Interiors

Making a Building more Environmentally Friendly

Sustainable Interior Design is also known as Green Interior Design. It is the process of making a building more environmentally friendly. This is a big task that can be divided into a number of different categories. The US Green Building Council (USBC) set up Leadership in Energy and Environmental Design (LEED) to set up metrics by which the building industry could evaluate how green and sustainable a house, office or building was. The metrics are divided into 5 main categories:

1) Reduction of carbon emissions
2) Conservation of water
3) Energy Saving
4) Indoor environmental safety
5) Careful use of resources

I believe it is beneficial to look at these metrics one by one to gain a better idea of what sustainable interior design is all about.

Reduction of Carbon Emissions

Despite those on the fringes of science and politics who claim climate change is caused by alterations in the sun's intensity or by a long cycle of weather patterns, or who just deny climate change altogether, the overwhelming majority now accept the evidence. This evidence that the levels of carbon dioxide in the air is increasing and that this trapping heat in the atmosphere and causing average temperatures to raise every year. It is undeniable that the polar caps are melting and that sea levels are also raising.

Much of the blame for this is down to mankind's economic activities. Burning fossil fuels since the Industrial Revolution has made a profound impact on the atmosphere. As economies increase so does the amount of carbon emissions. With the recent rise to prominence of such economies as China, Russia, Turkey and Brazil more carbon is being put into the atmosphere than ever before. At the same time photosynthesis by plant life that turns carbon into oxygen has decreased as more nature is cleared and more trees are chopped down. As the seas are being polluted plankton(also known as phytoplankton) is being lost that also absorbs carbon from the atmosphere.

A carbon footprint is the amount of carbon emissions given off for any given project. The aim of sustainable design is to reduce the carbon footprint of a house to a minimum. This is done in a number of ways.

  • Reducing transport carbon costs (trucks etc. usually burn petrol) by sourcing materials directly.
  • Looking at the carbon throughput of each item used for the building - quantifying how much fossil fuel was needed to make each item eg. mining for resources, transport, assembly etc.
  • Reducing the amount of energy that is not from a renewable energy supply that is needed to construct the building and to keep it running. Such factors to consider are heating and cooling and the use of photovoltaic panels.
  • The carbon emissions of those who construct the building  - ie. their transport costs and the carbon emissions  of the machines used for construction.
Every aspect of a building's interior and exterior can be assigned a carbon value.

Conservation of Water

Already many parts of the USA are classified as in a 'moderate to severe drought'. The fossil water supplies of India is approaching zero. 1 in 8 people already lack access to safe water supplies ( 70% of the world's fresh water is used on agriculture. As the world population grows more food will be needed and fresh water supplies will shrink even further. The UN estimates that by 2025, forty-eight nations, with combined population of 2.8 billion, will face freshwater “stress” or “scarcity”. (ibid). Make no mistake about it - water will be as important a commodity in the future as oil is now. Wars will be fought over fresh water supplies.

Against this backdrop it is very easy to understand why we should conserve water supplies in the home. An important part of green interior or sustainable interior design is about designing homes that need less water to make and use less water to run.

Energy Saving

Saving electricity is very important to green interior design or sustainable design. The aim of the Passive House is to keep an interior at a comfortable temperature without the use of heating or cooling devices. This is done by superinsulation that traps heat or cool air in a home. Only when it gets really hot or cold will a Passive House need inputs of heating/cooling. This can be powered by photovoltaic panels on the roof.

Most electricity is generated by burning coal, oil or natural gas. These are not only limited resources but the burning of these resources also increases carbon emissions. Burning coal also releases the heavy metal mercury that poisons ground water supplies. By using less electricity a home produces less carbon and uses less natural resources. The environment benefits with less pollution and less carbon in the atmosphere; and people benefit from less harmful pollution and money savings.

The metric of energy saving as laid down by LEED is a perfect example of the Triple Bottom Line - 'people, planet, profits'. It is the profit motive that drives a lot of sustainable design refits to a building. Saving energy saves money that can be used to pay for the changes and to eventually record profits.

Examples of energy saving methods include:

  • The use of solar panels and wind turbines to create clean, green energy
  • The use of a heat pump. It is 3 or 4 times more efficient than a regular electrical resistance heating system.
  • Switching from incandescent light bulbs to compact fluorescent light bulbs.
  • Using a programmable thermostat to avoid over heating or over cooling an empty building
  • Using a smart strip to override stand by on electrical appliances
  • Changing washing machines, air-con units, TVs and other electrical equipment to Energy Star recommended products.

Indoor Environmental Safety

Part of the role of a green interior designer is to make spaces that are healthy for people to live. People in the developed world spend 90% of their lives in doors. Due to lack of ventilation levels of polluting and unhealthy substances in the air can be 5 times higher indoors than outdoors. To make people healthier in their homes and offices it is essential to keep indoor air as free as possible of such things as volatile organic compounds, radon and dust mite excrement. This can be done by:

  • Replacing VOC containing products such as thinners, varnishes, paints, air fresheners, furniture glue with non VOC alternatives.
  • Sourcing antique furniture and other items for the home that has off-gassed all health threatening VOCs
  • Testing a home for radon levels
  • Installing bamboo, reclaimed hardwood or cork flooring
  • Using bamboo blinds and shades instead of curtains
Another big worry for indoor health are all the toxic and dangerous chemicals used in the home for cleaning. Green cleaning alternatives include using lemon, vinegar and baking soda.

Careful Use of Resources

Hardwood, coal, oil, natural gas, iron ore, aluminum and many other resources commonly used in the home and office are fast running out. If we are going to make homes that are sustainable we have to learn how to stop our reliance on these limited resources and instead find new and creative ways to use renewable resources that grow quickly enough to keep up with demand. Such renewable resources include bamboo, rattan, water hyacinth and cork. Other strategies are to use recycled resources or to take unwanted resources and turn them into something of higher value (upcycling) such as reclaimed hardwood flooring.

Where possible resources should be taken locally and with minimum impact to the local surroundings. If hardwood is needed then it is better that it is taken from a forest that practices sustainable forestry.

Furthermore, the impact of building in an area must be assessed and the damage to the environment limited as possible. Building interiors must also be designed as to reduce pollution to the surrounding area.


This is just a bare outline and a summary manifesto of how sustainable design is ideally practiced. The idea is that the methods, tests and systems for sustainable design should always be modified and improved; and should always respond to the needs of the local people and environment.

Our only hope for a secure future and a decent living standard for future generations lies in improving our ways of designing and building homes. They have a fundamental impact on us, the environment and the future. This places sustainable interior design at the heart of what the environmental movement is trying to achieve.

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