Debating the issue of green options in building

These days one can hardly open a newspaper or turn on the television without someone explaining how you should be behaving in a ‘green’ manner, in the interests of saving the planet or the welfare of your fellow human beings.

The bombardment of this green message relates to a desire to project a responsible attitude to the way in which one lives life. The message, in essence, says: do not be wasteful, be wise in the use of resources and be sensitive to one’s surroundings.

Overall this is a good and sensible sentiment; one that all reasonable people should have been taught from childhood by their parents and by society.

But the green message frequently does not stop there, it continues. The extension of the message of ‘be reasonable and not wasteful’ can then be extended to ridiculous proportions.

At this point the message starts to take on a religious fervour. People are emotionally advised by journalists or TV chat show hosts to show real commitment and do something visible, such as using bicycles rather than cars, or walking instead.

Fossil-fuelled power stations are condemned as being opposed to the objectives of mankind.

We are told that the ‘reasonable’ people, who we are told make up some rather significant proportion of mankind, all know this, but their opinions are being suppressed by skilful wealthy forces.

Then generally industrialists, who are the backbone of human progress, are condemned as being some dark force intent on destroying society.

The fundamental ‘green’ message is good, but many of its extensions become more akin to political hysteria. Many people are so scared by the tidal wave of green sentiment that they are far too afraid to speak up against it when aspects appear to be illogical or impractical.

This sentiment results in a spread of initiatives and reactions over a wide spectrum of activities. Many of these are definitely beneficial and sensible, while others are foolish and of dubious benefit to the planet and to the people who inhabit it.

Green building

Linked to this overall green movement has come calls for society to move towards green building construction. Conferences are held, with ‘green building’ as a theme. Government departments and municipalities around the world declare themselves in favour of green building, but often it is more a case of the political leader who is making the statement, trying to be seen in the correct political light.

Now that the general politics of the world has made the ‘green’ concept so fashionable, we have to take a careful professional look at this issue of green building.

In debating the issue of green building, a spectrum of people ranging from professional architects to vociferous laymen point out factors such as the notion that houses can be built in a more energy efficient manner, or that households can make their own compost… the list of options is expansive and diverse.

However, we now have to stop and ponder the question. There are essentially two options to consider when watching the chanting cheerleaders of the ‘build green now’ movement.

The one option is to follow the professional path of designing and constructing buildings to be the most economic, efficient and effective structures possible.

The other green construction optionis the political option of being publicly seen to be going green even if, in reality, the proposed green construction does not make economic sense.

Of course, it is possible to follow a mixture of these two options.

We will now consider only residential housing. Commercial and industrial buildings are certainly not exempt, in fact, they offer a whole alternative and additional set of options to include.

Green options

In considering the spectrum of green options in building, there are many.

As far as the building itself is concerned, there are issues of energy efficiency for starters. This topic in itself is vast and is touched on only briefly here – to do it justice would take an entire book in its own right.

Other factors that can be designed into a building include the recycling of water or perhaps the routing of used grey bathwater to other uses such as to flush toilets. There is also potential provision to be made for the separation of kitchen waste into separate bins for glass, metal, plastic and so on.

The entire design of the house can be developed to optimise temperature stability, allowing sunlight to penetrate the living space to warm the house in winter, but reflecting sunlight away in summer to assist in keeping the place cool.

There are options to make optimum use of sunlight for illumination to avoid using more artificial light than necessary. There are the possibilities of installing solar thermal heat collectors on the roof or solar photovoltaic cells to produce electricity. Or perhaps a small wind turbine can be installed to produce electricity as a supplement to the building’s consumption from the electricity mains.

There are indeed many options that can be considered, but the questions that the building economist has to ask are: how much of this green construction really achieves an economic objective; and how much of the green construction may merely be carried out with the objective of making the owner feel righteous in the eyes of friends, family and the community?

Energy efficiency

Let us dwell on the issue of energy efficiency for a moment. In principle, energy efficiency is measured by how much the owner pays on his monthly electricity bill.

So installing a solar photovoltaic array on a suburban house may well produce some electricity that is not purchased from the municipality, thereby reducing the monthly electricity bill.

But what do we do about the capital cost of installing the system? Do we simply put it into the bond repayment on the house or should we possibly, more correctly, divide it into a 10- or 20-year repayment on the monthly electricity bill?

Modern options for electricity saving in the home are available. These include installing compact fluorescent light bulbs instead of the traditional incandescent ones. Even more exciting are the new light-emitting diode (LED) lights, which are now becoming available at an increasing rate and on a reducing price curve.

But LED lights are different in characteristic to the traditional incandescent bulbs. They produce more directed beams, more like a torch, than the traditional idea of an all-round light bulb glow. This then implies that architects and interior designers will have to think about lighting in a different way.

Probably many new lighting designs will be such that rooms will no longer be lit by a primary light fitting hanging from the ceiling in the centre of the room. LED clusters will probably be tucked away in corners or perhaps near ground level, directing light to features or to reflecting surfaces.

The concept of energy efficiency in the modern home is not simply a case of changing the bulb, rather a case of the designers thinking in a different mode.

The same is true of air-conditioning, the stove, space heating and more. Perhaps it will turn out to be profitable to electric motors to windows to automatically open and close them, depending on the temperature difference between the inside and outside air. The technology certainly exists to do this.

Lighting and air-conditioning can also be connected to motion sensors. If the sensor detects no human movement in the room, for say half an hour, it would turn off the device.

But it could be more complex than this, one may want air-conditioning to operate while a person is asleep, or a small child’s night light may need to stay on in the room all night. All these requirements can be programmed into electronic controllers. Decisions have to be made concerning the economic and social costs and benefits of such actions.

Simple energy-saving decisions include such actions as setting a household swimming pool timer to come on at 03h00, rather than at breakfast or dinner time. This is not actually an energy saver for the homeowner, as there is no reduction in the monthly electricity bill, but it does help the national power production system by load shifting to a time of less demand.

How large is the circle?

So where do we draw the circle around our area of concern in applying our green decision-making?

Is it only the house or is it the entire property? Do our decisions affect our neighbours?

The extreme green sentiment draws the circle much larger than the house, in fact, it can be drawn larger than the whole country if we are trying to save the planet.

In examining building economics, one could take the position that reducing the electricity consumption of many houses could result in the municipality having to lay smaller supply cables to the neighbourhood. This would not help the economics of the construction of the house, but it could help the economics of the city and so, in the long run, lead to lower rates and taxes.

In choosing building materials, one could choose to ‘build green’ by using natural wood finish instead of aluminium or polymer surfaces. One can avoid paints that are not water-based or avoid paint altogether.

It is largely with these types of decisions that one moves from the realm of true day-to-day building economics into the realm of domestic and international green politics.

Now is the time for sober introspection. At green building conferences, seminars and study groups one must ask: to what degree is the sense of international co-operation and the toeing of some line produced somewhere, by someone, for some reason, influencing our decisions about the real economics of constructing buildings that are sensible, well constructed, energy efficient and in tune with a responsible attitude towards economic construction?

Where to?

It is an understood reality that buildings are built differently in a country that is often covered in snow, in comparison to construction practice in a hot dry climate such as most of South Africa experiences.

However, when green building is spoken about, it tends to become ‘internationalised’ in a spirit of enthusiasm and one finds South African magazines advocating installing triple glazing to retain heat in winter. Frequently one can see that the article, or advice, was lifted straight out of some European journal.

The sentiment of effective and efficient building is undoubtedly good, but local talent must develop solutions and innovative approaches that are appropriate for our climate and requirements.

Good sense and a professional approach must rule the day, and not a slavish adherence to a perceived superiority of knowledge and technology apparently exhibited by foreign countries far from our shores.

South African professionals are good, and should have the self confidence to make their professional opinions known in this volatile field. 

The authors, Dr Kelvin Kemm and Professor Chris Cloete, have been working on building efficiency issues as part of the ongoing work of the Department of Construction Economics at the University of Pretoria. Dr Kemm has a PhD in nuclear physics, while Prof. Cloete has a PhD in analytical chemistry. They believe in applying scientific principles to the issues of energy efficiency in building construction.

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