Building sustainability: Energy efficiency

In an era of increasing environmental consciousness, particularly after the impact of global warming on the different countries around the world with varying intensities, the concept of building sustainability has gained significant importance. It is not by choice that we must act now, but for necessity, as buildings heating and cooling activities in the EU, for example, consume almost 40 per cent of Europe`s energy consumption and emits 36% of its greenhouse gases. In Jordan the consumption of electricity for residential and public buildings reaches 48 per cent. Therefore, building sustainability through energy efficiency for the conservation of energy and water is crucial in a warming world that anticipates difficulties in confining raising average temperatures to 1.5 to 2ºC by 2050, at a time when we have reached 1.1 degrees above the world average at the start of the industrial revolution around the end of the 18th century.

As the world wrestles with the challenges of climate change, fluctuation in the intensity of precipitation, temperatures, water levels, pollution, and resource depletion, it is crucial to tackle one the main themes that underpin sustainable buildings, which is energy efficiency. This article aims to broadly explore and highlight key themes of energy efficiency that contribute to the overall sustainability of buildings, emphasising its impact on the environment, including human beings and their societies, issues such as: Passive architectural design, thermal insulation, energy efficient of electrical appliances, human health, building sustainability, economy resilience and societal stability in general.

It is not an exaggeration to say that one of the fundamental pillars of building sustainability is energy efficiency. This can be practiced through designing, retrofitting and constructing new buildings that are capable of minimising energy and water consumption and hence maximise energy efficiency which can eventually mitigate global warming and control rising poverty worldwide. So, what are the key issues in energy efficiency?

Key elements in energy efficiency include passive architectural design, such as building orientation, shading practices, glazing to exterior envelope, controlling heat islands, etc., as well as efficient, sustainable and eco-friendly thermal insulation accompanied with proper water proofing, the use of renewable energy sources (such as solar or wind power), smart and efficient lighting systems, and advanced HVAC (heating, ventilation, and air conditioning) technologies. This overall management of energy and water efficiency eventually depends on responsible human behaviour that requires incentives, ethics, nurturing and education.

Energy-efficient buildings reduce energy and water consumption, hence reduce carbon emissions and lower operational costs, reduce cracks (thermal, shrinkage and expansion cracks) and increase thermal comfort which consequently upgrade health conditions of the occupants, while inciting a more efficient human productivity for the whole economy in terms of increasing working hours of healthy, active and responsible citizens. Also installing enough thermal insulation on the outside of the external envelope reduces thermal movements of the building structural frame caused by temperature variations between the seasons and during day and night. 

As for human health considerations, sustaining the interior ambient temperature between 18 and 20ºC reduces risk from heart attacks and other brain diseases if the temperature falls below 18 degrees in winter, and avoiding thermal discomfort and heat strokes above 25 degrees in summer, as well as spending less on energy, thus upgrading the economic livelihood of families. In summer, using traditional fans can be useful to avoid installing AC units, in some cases and climatic conditions, as fans can increase the thermal comfort zone, by 2-4 degrees in particular situations.

Smart windows and shutters can also control the amount of light and heat that enters or exists a building, reducing the need for artificial lighting and cooling. Also important is using a smart technology making outside openings airtight and properly shading windows facing direct sunlight according to the direction of the sun, as shades can be from the outside or the inside, vertical or horizontal, depending on the orientation. Special glass controls emissivity, radiance, reflectivity, shading, ultra violet light and other factors that should be chosen according to climate and orientation. The most malfunctions in hot climates is increasing the exterior glazed area as the internal spaces start behaving like green houses in summer and thus increasing the cooling load dramatically. Inversely in winter it can lead to substantial losses of energy.

Energy efficiency includes using low emitting diodes bulbs, installing motion sensors, timers, reducing water pump speed, managing a regular maintenance of electro-mechanical systems, such as boilers and pumps. Also constructing green roofs and walls, as well as upgrading the thermal qualities of the exterior envelope. Building energy efficiency also includes replacing old electrical equipment by new energy efficient ones, such as fridges, dish washers, laundry dryers, hairdryers, electrical space heaters, irons, and above all installing heating and cooling units with inverters whenever applicable and replacing electrical water heaters by solar water heaters.

Other innovative energy efficiency procedures include Phase Change Materials which are substances that can store and release large amounts of thermal energy during phase transitions between day and night, sometimes expressed as thermal mass, which is necessary for thermal comfort in our Mediterranean climate. This can be achieved by choosing the suitable building materials facing towards the internal spaces, including furniture, etc. However, such practices can be uncomfortable in hot climates such as the Gulf area and in public buildings that are usually occupied intermittently, and therefore other solutions should be sought. 

In conclusion, energy efficiency is a procedure that combines theory with practice and through that inter-connectiveness one can discover innovative ideas that may be applied to new and existing building, residential, public, commercial or industrial and learn from other people experiences and by trial and error in unique situations. Energy efficiency is not a procedure that yields economic implications only, but also impacts environmental, health, sustainability, social equity, justice and also has ethical considerations that can lead to societal stability in general.

Ayoub Abu Dayyeh is an adjunct lecturer at Al Zaytoonah University. He contributed this article to The Jordan Times.