Energy efficiency in buildings
Eight steps towards sustainable construction
In our daily lives, we use a whole range of different buildings: from our homes and workplaces to schools and healthcare centres. In each of these we consume energy for heating, cooling, hot water supply, ventilation and lighting. The importance of electrifying buildings to optimise their energy efficiency is clear.
Iberdrola Tower, the energy of an idea. Video voice transcription (Spanish version) [PDF] External link, opens in new window.
Sustainable architecture promotes energy efficiency in buildings to prevent unnecessary energy consumption, make use of local resources to power their systems and eliminate negative environmental impacts. According to the International Energy Agency, the building sector accounts for around 30% of global energy consumption, making it a strategic area for the use of clean energy and the advancement of electrification. In this regard, Iberdrola is a member of the Madrid World Capital of Construction, Engineering and Architecture Association (MWCC), as a leading advocate for electrification, contributing its expertise and technical capabilities to the association's projects at both national and international levels.
Innovative techniques, new materials and technological advances in construction are significantly boosting the energy efficiency of new buildings worldwide.
The key lies in an approach that combines bioclimatic design, recycled materials, building envelopes and thermal insulation and sustainable habits:
- Selecting a location and orientation that make the most of the sun and wind to reduce energy consumption.
- The use of recycled building materials sourced from local suppliers to reduce the carbon footprint associated with transport.
- Thermal protection in walls, roofs and windows to minimise heating and cooling requirements.
- Implementing new technologies such as evaporative cooling towers, water recycling systems, solar panels, aerothermal systems and smart temperature and humidity management.
- Promoting environmentally responsible lifestyles such as clean transport, vertical gardens and the collection and treatment of rainwater.
What makes a building energy-efficient?
An energy-efficient building is one that minimises the use of non-renewable energy and performs the same operational functions with significantly lower energy consumption. It uses clean energy, such as solar, wind and geothermal power to light, heat, ventilate or cool a property.
Builders construct these buildings using materials that are environmentally friendly, save energy (and even generate it) and outperform conventional buildings in terms of energy consumption, lower utility bills, reduced greenhouse gas emissions and occupant comfort.
For a building to be considered energy-efficient certain factors must be taken into account:
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Building envelope
The building envelope must be capable of minimising energy losses and maximising solar energy gains. Designers achieve this by using suitable materials for windows, doors, roofs and walls and by implementing thermal insulation measures.
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Use of renewable energy
The use of solar, wind, geothermal or aerothermal energy for lighting, heating and cooling and domestic hot water in the property.
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Energy-efficient equipment
Air-conditioning systems tend to consume a great deal of energy in buildings. It is essential to strike a balance between energy consumption and comfort levels.
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Efficient lighting
Smart lighting systems that switch on when someone is in a room and switch off when they are not. Furthermore, the building's design must make the most of natural light.
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Energy management
It is advisable to implement smart energy management systems, as these help to monitor energy consumption and identify areas for improvement.
Case studies
Here are some examples of sustainable buildings:
Torre Iberdrola
The Torre Iberdrola, located in Bilbao, Spain, features energy-efficiency systems, water treatment facilities, the use of renewable energy and low-emission materials. It also has parking spaces for hybrid and electric cars. It was the first building in Spain to achieve the highest rating under the LEED sustainable building certification system.
Bullitt Centre
The Bullitt Centre is a commercial building in Seattle, USA, constructed using more than 350 materials that are neither harmful to health nor the environment, and which is 99% energy self-sufficient.
Bahrain World Trade Centre
This complex, located in Bahrain, has three wind turbines that supply around 15% of the buildings' electricity. It also features reflective pools that help to cool the interior.
Ng Teng Fong General Hospital
Ng Teng Fong General Hospital is a medical complex located in Singapore. It relies on natural ventilation for 70% of its airflow thanks to a fan-shaped design that makes the most of strong breezes. In addition, the façade incorporates landscaped terraces.
Certified sustainability
Many organisations have developed seals of excellence over the last years to push the trend towards sustainable construction, promoting innovation, and energy efficiency: LEED
External link, opens in new window., BREEAM External link, opens in new window., Passive House External link, opens in new window. or Living Building Challenge are some of the most prevalent ones. Companies, public bodies, and architecture firms around the world compete for certification.
How is building sustainability measured?
The LEED certification, awarded by the Green Building Council in the United States, scores 8 prerequisites needed for sustainable construction:
Location and transportation
- Avoid building in natural environments
- Reduce the duration of car trips
- Encourage public transit and physical activity
Sustainable sites
- Protect or restore the local habitat
- Revitalize abandoned areas
Responsible waste management
- Efficient re-use
- Irrigation system control
- Moderate consumption
Energy and air quality
- Demonstrate a percentage of energy savings
- Use clean, renewable energy
Materials and inputs
- Recycled, renewable, or Green Seal-certified materials
Interior air quality
- Ventilation
- Temperature and acoustic comfort
- Proper lighting
100 points
Design innovation
- Proposals for new conservation strategies
Regional priority
- Attend to local environmental issues
10 points
LEED Certifications
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Certified 40-49 points
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Silver 50-59 points
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Gold 70-79 points
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Platinum More than 80 points
Energy-efficient refurbishment
Making an existing building more energy-efficient requires an energy audit. This assessment determines current energy consumption and environmental impact, assigns an energy rating (from A to G) and proposes measures for improvement.
Generally, refurbishment work focuses on:
- Insulation: This involves improving the thermal protection of the property, mainly on the façade and the roof.
- Air-tightness: This aims to prevent air leaks through grilles or gaps in windows and cracks in walls or floors.
- Ventilation: Installation of controlled systems capable of reducing heating demand by up to 90%.
- Lighting: The implementation of smart systems that optimise energy consumption and maximise the use of natural light.
- Renewables: Installation of solar panels for self-consumption in both residential buildings and businesses to support this transition.
The International Energy Agency (IEA) recommends taking into account whether infrastructure refurbishment is taking place in developing countries or not. On the one hand, in more advanced economies the number of buildings is growing at a slow rate. For this reason, progress in efficiency is driven by accelerating refurbishments to reduce the demand for air conditioning and the electrification of heating. On the other, in developing economies the priority lies in proper urban planning and the construction of energy-efficient buildings.
The role of electrification
The building sector has significant potential for electrification to replace traditional fossil-fuel-based heating and hot-water systems. This can help reduce emissions from buildings. Furthermore, devices such as heat pumps can deliver greater efficiency, as they are generally more efficient than gas boilers. Phasing out the latter improves indoor air quality. Another advantage of electrification is grid flexibility as smart controls enable buildings to better manage energy demand during peak hours.
However, realising these benefits requires overcoming several challenges, such as access to the electricity network, barriers to adoption and the need for incentives. The building sector competes with other sectors, such as data centres and industry, for capacity on the electricity network in a context where energy consumption is not keeping pace with the production of renewable energy. Furthermore, the high upfront costs of equipment and the limited physical space in existing homes present a barrier that requires public policies to narrow the price gap between electricity and fossil fuels in order to accelerate the transition.