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What are energy efficient buildings?

Energy efficient buildings use the least amount of energy possible. They use technology, sustainable materials, and smart design strategies to minimise energy consumption. 

For example, an energy efficient building might be constructed using high-performance insulation. It may use energy-efficient windows, and state-of-the-art heating, ventilation, and air conditioning (HVAC systems). It could also make use of renewable technology like solar panels. 

Overall, energy efficient buildings provide significant long-term cost savings. They contribute to environmental sustainability, and promote a greener future.

What is the difference between energy sobriety and energy efficiency?

Although these two approaches aim to achieve better energy management, their processes are different.

Energy efficiency aims to reduce consumption. It does this by improving the performance of equipment like HVAC systems, insulation, and household appliances. It’s concerned with using less energy to perform the same task, or to produce better results (like cost savings). 

Energy sobriety, on the other hand, refers to the collective effort of reducing energy waste. In other words, it aims to reduce energy consumption through voluntary yet deliberate action. It encourages behaviour change, promoting practices like car sharing, teleworking, and cycling. 

At Equans, we’ve signed the Ecowatt charter in France, and implemented our own sobriety plan for wherever the company operates in the world. 

The role of energy efficiency in industrial sustainability

Research from Deloitte finds that in 2002, 75% of Chief Experience Officers increased their sustainability investments over the past year[1]. Indeed, energy efficiency has become a cornerstone in the quest for achieving sustainability across industries.

Organisations are increasingly focused on producing goods using minimal energy. Consequently, they’re reducing their waste and minimising their environmental impact. 

Many companies are prioritising energy efficiency across the entire product lifecycle. They’re carefully selecting materials and components, and optimising processes and supply chain practices.

[1] https://www.deloitte.com/global/en/about/press-room/new-deloitte-research-on-sustainability-investments.html

How to calculate energy efficiency ?

Measuring energy efficiency is key for businesses that are striving to reduce their CO2 usage. The following formula can be used to calculate where energy is being used, how much is being wasted, and how much is going where it should: 

Energy efficiency = (useful energy output ÷ total energy input) x 100

This equation can be used to determine the percentage of energy that’s being used effectively for a given purpose. To begin with, the energy that’s going into the system needs to be calculated in watts or joules. Then, the useful energy output needs to be determined using the same unit of measurement.

The energy output is divided by the energy input, and an energy efficiency ratio is calculated. To express the ratio as a percentage, multiply it by 100.

For example, say a heating system has an energy input of 100,000 kilowatt-hours (kWh). And its total energy output is measured at 85,000 kWh. 

100,000 ÷ 85,000 = 0.85, or 85% efficiency.

How to improve an Energy Performance Certificate (EPC) rating?


An Energy Performance Certificate (EPC) demonstrates how energy efficient a building is. The rating is similar to those found on household appliances. EPCs rate a building on a scale from A (very efficient), to G (inefficient). They provide an indication of how expensive it is to heat and light a property, and what its CO2 emissions will be. 

An EPC also indicates what the energy efficiency rating could be if recommended improvements are made. Typically, EPC ratings can be improved by conducting energy audits to identify inefficiencies. Energy-saving technologies can then be installed, and buildings can be retrofitted with more efficient materials. 

Likewise, smaller actions can help improve an Energy Performance Certificate Rating. Improvements like installing LED lights , insulating hot water tanks, and installing double glazing windows can all make a difference.
 

Are smart buildings energy efficient?

Yes, smart buildings are energy-efficient. They’re designed using advanced technologies like the Internet of Things (IoT) to manage energy use in real-time. They also optimise heating and lighting systems, which reduces overall energy consumption.

Smart buildings also use automated systems to control lighting, heating, cooling, and ventilation. When used in combination with real-time data (like occupancy levels), these systems ensure energy is only used when required.

These buildings also use data analytics to predict when equipment is likely to fail or become less efficient. This means that maintenance can be carried out quickly, reducing the energy losses associated with underperforming systems.
 

How to design energy efficient buildings ?

Energy efficient buildings start with smart design. Architects, designers, and builders need to plan energy efficiency measures in advance and ensure they can be implemented cost effectively. For example, a compact building shape reduces the surface area through which heat can escape. 

Likewise, incorporating specific design features can ensure a building’s energy efficiency. For example, large windows on the south side, thermal mass materials (like concrete or stone), and shading devices are all effective features. Typically, energy modelling is used to evaluate energy efficiency during the design stage. 

Insulation materials with high R-value can be used in walls, roofs, and floors to reduce heat loss in winter and keep buildings cool in summer. Likewise, air sealing ensures that building envelopes are airtight to prevent drafts and heat loss. 

Solar panels are typically used to generate electricity, and solar thermal systems are often used for water heating. Similarly, geothermal systems can be used to leverage the stable temperatures underground for air heating.

Glossary

Energy efficiency - The practice of using less energy to perform the same task, or produce the same outcome.

Energy consumption - The total amount of energy used by a system, process, or device.

HVAC systems - Heating, Ventilation, and Air Conditioning systems regulate indoor environmental conditions by controlling temperature, humidity, and air quality.

Energy sobriety – The voluntary and deliberate reduction of energy consumption through minimising wasteful practices.

Energy Performance Certificate - An official document that provides the energy rating of a building.

Smart building - A building that uses advanced technologies and automated systems to optimise energy use and sustainability.

Energy modelling - The process of using computer-based simulations to predict and analyse a building's energy consumption, efficiency, and environmental impact.

Thermal mass materials - Building materials that can absorb, store, and slowly release large amounts of heat, helping to regulate indoor temperature fluctuations.

R-value - A measure of a material's resistance to heat flow, with higher values indicating better insulating properties.

Geothermal systems - Energy systems that harness the stable temperatures beneath the earth's surface to provide heating and cooling.

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