Green building is cheap and efficient

The widespread belief that green building is expensive has seen many developers steer clear of it in favour of conventional styles. However, they are mistaken.

“The notion that green building is expensive is a fallacy. A well-designed green building can actually be cheaper to build than a conventional one. It all depends on design,” Mr Kevin Oduor, principal architect and CEO of Do Design Consultants (DDC Architects) told DN2 at the  Panari Hotel in Nairobi, which he retrofitted a few years ago to make it more sustainable.

One of biggest misconceptions, Mr Oduor notes, is the belief that a green building encompasses a lot of technological devices and gadgets, which override the cost. However, a green building looks at environmental sustainability and efficiency in energy and cost.

“These three aspects are the defining factors of a green building. So if you put up a building that caters for the environment, saves energy but does not take into account the cost aspect, that is not a green building. If one of these three aspects is missing, then it does not qualify as a green building.”

So, what does he make of the towering structures with lots of glass that are sometimes mistaken  for green buildings.

Mr Oduor says green architecture sets itself apart by looking at the whole life cycle of a building, considering the planning, siting,  design, construction, operation, maintenance, renovation and demolition, as opposed to just the design. 

“Looking at the life cycle of a building, therefore, helps predetermine the total cost, which is pegged on two pillars: construction costs and cost of running the building,” he says, adding that the latter includes the power bill for lighting and running house appliances, besides the water bill.

ZERO RUNNING COSTS

Bills enable a property owner to track their spending, and Mr Oduor says that in a green building, one is assured of minimal spending because the building’s orientation ensures that it receives natural light, for instance. Besides, a green building  not only harvests rain water, but also recyces and re-uses it.

“With a properly designed green building, you save at least 30 per cent on energy because solar panels can generate enough power to light your house, and you can sell excess power to the grid,” says Mr Oduor.

Mr Oduor, who  has undertaken major projects not just locally but in Tanzania, Cameroon and Bukina Faso, says his next housing project, whose pitch is at an advanced stage with a major housing financial institution in the country, is going to be “net-zero running cost”.

“This basically means you’ll get into a house and  will not spend a cent on electricity and water. Power will come from renewable sources such as solar and wind harnessed directly into your house, which   will also be water self-sufficient. So the only cost you will incur is maintenance, which I believe is negligible,” says Mr Oduor.

Meanwhile, he says the glass cladding so common in modern buildings is a mere replica of designs in the West, whose weather pattern is different from sub-Saharan Africa’s.

“I know of a building on Uhuru Highway where, at around 3pm, the occupants place newspapers on the windows to shield themselves from the sun. Meanwhile, the glass walls reflect the sun’s rays, making the area extremely hot and uncomfortable in the afternoon,” he says.

He adds that the problem with glass cladding is that, while it might be fashionable, it is not timeless, meaning it serves only the needs of the current user, but might not be conducive or functional for future users. In fact, these glass towers tconsume a lot of energy because they need to be cooled  artificially,  making them unsustainable.

Mr Oduor echoes the sentiments of the chief of UN Habitat’s Urban Energy Unit, Dr Vincent Kitio, who last year expressed concern that many modern buildings in  sub-Saharan Africa are simply “replicas of those designed for the Western world, whose climate is different from sub-Saharan Africa’s”.

He regretted  that the new buildings do not take into consideration the two major aspects of sustainability: the local environment,  and the local economy in terms of how affordable it is to put up the structure.

Dr Kitio cited inefficient design and construction using unsuitable materials, coupled with poor understanding of building principles, as major problems dogging local construction. 

Citing ICEA Building on Kenyatta Avenue and IPS Building on Parliament Road in Nairobi as some of the buildings put up with the tropical weather and sustainably in mind, Mr Oduor says that far from “the brainwashing that he international building style is the way to go”, a number of factors go into making a building green.

“First is the use of locally available material. This not only reduces  construction costs  by reducing transportation costs, but also creates a host of environmental and social benefits for a community, for instance, empowering the local labour force. Environmentally speaking, few footprints are left behind at the end of the house’s life cycle, which is the whole idea behind green building,” says Mr Oduor.

PROPER POSITIONING

Meanwhile, though largely ignored, one of the most important factors to consider is the orientation of a building.

A building should not have large windows on the east-west axis, and the material used to build the walls on that axis should be able to absorb heat, such that they keep the building cool during the day and more importantly, dissipate that heat at night, thereby  making the house warm.

Noting that at least 70 per cent of the energy costs in a building is consumed during maintenance through lighting, air conditioning, and cooking, Mr Oduor says that a simple building principle like positioning the house properly eliminates the need for air conditioners.

He says the government should consider banning the use of chlorofluorocarbon (CFC) air conditioners because they contribute to global warming.

Mr Oduor notes that, of a country’s total energy consumption, buildings take up the most - about 40 per cent. Most of this is through burning fossil fuels that contribute to environmental pollution.

“With buildings taking the lion’s share, therefore, we in the construction industry have a bigger part to play to control global warming,” says Mr Oduor, adding that heavy energy consumption can be solved through sustainable development.

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What should be done?

Legislation: Even though the government has taken a big step forward by enacting the Energy (Solar Water Heating) Regulations 2012 that compels developers of residential premises (three-bedrooms and above), health institutions, restaurants and hotels, boarding schools and other similar commercial operations to install solar water heating panels on their buildings, Mr Oduor believes that a lot more needs to be done in terms of legislation.

“The government should come up with better laws and incentives to promote sustainable living. This should come in  the form of tax rebates to developers of green building, but more importantly, the government should come up with standards and directives on green building and create a monitoring arm to ensure compliance,” says Mr Oduor.

Education: Institutions of higher learning have a big role  to play by making green building central to their teaching. In addition, more awaresness should be created regarding the cost of green buildings.

Energy labelling: Mr Oduor says the authorities should introduce energy certificates for all buildings and households so that tenants are aware of  a building’s  performance with regard to energy.  He says this will help them look beyond rent and into the underlying costs before occupying a building.

Creating a balance: Mr Oduor says that in an ideal situation, the environment should be self-sustaining in that animals and humans rely on it, and vice versa. However, while humans rely on the environment for resources, they do not treat it well. And the result of this imbalance is detrimental, if left unchecked. 

“Looking at 100 per cent sustainability implies that there should be a clear balance between the resources we consume and those we add to the surrounding. This means that we should replenish the stock of water we consume from the environment by planting trees, which will also act as a mitigating factor to the carbon dioxide we release to the environment. That way, we will maintain the balance,” says Mr Oduor.

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GREEN IS ABOUT ALL-ROUND CONSERVATION

Lake Nakuru Sopa Lodge

Overlooking Lake Nakuru and the surrounding National Park, Lake Nakuru Sopa Lodge is where DDC’s green building journey began six years ago. The lodge, which lies in the western part of the  Rift Valley in Nakuru County, was built largely using locally available materials. The walls were built using light-coloured, naturally soft masonry blocks, which makes them reflect excess heat from the sun. In addition, their thickness (about 25cm) ensures that they have a high thermal mass, meaning they absorb heat during the day and release the “stored” heat at night.

Mr Oduor says that the beauty of using local materials is that they have low embodied energy, meaning very little carbon is burnt to produce them, making them environmentally friendly. He further notes that local materials are naturally designed for a particular environment as opposed to imported material. Besides, using local material helps uplift the economy of the neighbouring community.

The lodge is  modelled to merge with the surrounding environment, with access paths made of natural stones and lined with wooden rails. Besides reducing the cost of construction, it will leave few environmental footprints at the end of its life cycle. The timber shingles roofing system that blends well with the environment collects and channels rain water to large storage tanks. The lodge is also landscaped to conform with the surrounding hilly terrain.

All the rooms have large glass windows which, apart from offering a magnificent view for birdwatchers and wildlife lovers, naturally illuminate them, reducing the need for the more expensive artificial lighting.

Meanwhile, the lodge is positioned in such a way that it is not hit by direct sun rays.

Mr Oduor says that even though its construction cost was slightly lower than would have been  the case using conventional method, the relsaving is on running costs.

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Magma Square

(Githunguri office block)

From a distance, this building in Githunguri, Kiambu County, which was designed by DDC Architects, who also supervised its construction,  appears like an ordinary, glass-cladded office block. However, it is a green building.

For one, it has  small windows on its east-west axis, which are enhanced by sun blocking devices.

The building uses the stack effect for thermal regulation. Simply put, stack ventilation uses temperature difference to move air. Usually, hot air rises due to buoyancy and the low pressure created sucks in fresh air from outside.

Mr Oduor says when the air in the building’s lobby, which is its central point, warms up, it draws air from the offices and  then up through the ventilation channel. This passive cooling means that the building has little need for  air conditioners.

The walls have a high thermal mass, such that when hit by direct sunlight they absorb the heat.

“That is basically due to the material from which they are made and the design,” Mr Oduor says. 

Harvested rain water is stored and then pumped up to the roof for use in the washrooms, reducing the building’s reliance on piped water. 

On waste management, DDC have come up with a policy for training the building’s occupants on how to manage solid waste. 

Interestingly, Mr Oduor reveals, the building cost 25 per cent less to construct than would have been the case using conventional methods for a building of the same size.