Green Building ROI (Return on Investment)

East Asia: An IFC study on different building sectors using the EDGE Building APP.

Recently the International Finance Corporation (IFC), a division of the World Bank, undertook a study of green building measures employed in buildings in the East Asian region using the EDGE Building App to see what the typical ROI was. The study was done by several college students from the Georgetown University McDonough School of Business as part of their education on sustainability. This was a desktop study using the Edge software and providing a summary of key takeaways for best interventions given the local climate. The object of the study was to discern what the most effective choices are in passive building design to lead to the lowest possible payback and lowest costs for investors and builders.

For the EDGE System, a project must achieve savings of 20% in three categories: Energy, Water, and Materials Efficiency. The Edge App online has metrics built into it based on accepted international standards for Water and Energy usage, and for carbon footprint values for the Materials efficiency section. A series of sustainable building measures are chosen for each category, and these combine to achieve the 20% savings. Costs for materials are based on market values in an online database, which the IFC regularly researches and updates.

Some notes about the study:

  1. EDGE default values were used for the building data.
  2. The buildings were assumed to be in the country’s capital city. For larger countries the results may be different due to varying climates across geographic regions.
  3. Buildings in the Education and Light Industry categories are based on the EDGE application only. No buildings were certified as of the time of the study in these categories in the EDGE system.

This article will review the key observations for each of the building categories in the EGDE system that contributed most to savings.

  1. Homes:
    The most effective intervention in the Homes structures were in the areas of lighting, cooling, and heating energy. In the case of warmer climates such as Fiji, Cambodia, and Indonesia energy savings were achieved by choosing natural ventilation strategies, energy saving light bulbs, and low-e coated glass. In cooler climates choosing an efficient air conditioning and heating system achieved the best energy savings. Water savings were created using low-flow showerheads, low-flow faucets, and dual-flush toilets. These choices for water typically save a significant amount in most projects making it easier to get to the 20% requirement. Changing the Floor slab to a more low carbon choice was the most common way found to meet the requirements in the material efficiency category. The ROI generally was less than 2 years when all of these measures were employed for Homes in the different countries in the study.
  1. Hotels:
    The most effective intervention in the Hotels structures were in the areas of lighting, water, cooling, and heating energy. Air conditioning is almost always the biggest energy load for hotels. Choosing an efficient air-cooled or water-cooled chiller contributes a great deal towards getting the 20% energy benchmark for EDGE. Energy saving light bulbs also contribute significantly to savings. As with the Homes section, water savings are best created using low-flow showerheads, low-flow faucets, and dual-flush toilets. Grey water systems can also be effective. The study found that as in the case of Homes Floor slabs were the biggest cost driver and embodied carbon savings could best be achieved with low carbon materials. The ROI generally was less than 2 years when all of these measures were employed for Hotels in the different countries in the study.
  1. Offices:
    The most effective interventions in the Shopping Center structures were in the areas of shading, lighting, and heat recovery. Providing architectural shading produced energy savings, along with and efficient air conditioning system, reduced window to wall ratio as well as insulation. Water savings were achieved in the case of offices making use of black water treatment and recycling, grey water treatment, and water efficient kitchen sinks. Floor slabs again were found to be the best way to achieve material savings. The ROI was less than 1 year when all of these different measures were employed for Offices in the different countries in the study.
  1. Shopping Centers:
    The most effective intervention in the Shopping Center structures were in the areas of lighting, heating, cooling, and food court energy. Energy savings were found commonly in measures such as roof insulation and natural ventilation. A Reduced Window to Wall ration also contributed to savings. As with most building types, energy saving light bulbs also contributed significant energy savings. For cooler climates heat recovery from exhaust and roof insulation also contributed to savings.  Water savings choices such as Dual Flush Toilets and grey water recycling created the most savings. For the material efficiency the choice of floor slab again contributed the most to embodied carbon savings.  The ROI was less than 1 year when all of these choices were employed for Shopping centers in the different countries in the study.
  1. Schools:
    The most effective interventions in the School structures were in the areas of heating, and cooling energy. Energy savings for schools were achieved by choices similar to other building Categories such as Roof and Wall Insulation, Low-e glass, and reduced window to wall ratios. The study also found though that Natural ventilation in corridors and the use of energy efficient ceiling fans also were a great boon to energy savings. In fact often a 15-20% savings could be achieved by the ceiling fans alone. As with other buildings for water savings, common efficient fixture choices such as low-flow washbasins, dual flush toilets, water efficient urinals, and water efficient kitchen sinks were very effective choices. Again for the material efficiency the choice of floor slab contributed the most to embodied carbon savings. The ROI was less than 1 year when all of these measures were employed for Schools in the different countries in the study.
  1. Hospitals:
    The most effective intervention in the Hospital structures were in the areas of lighting, and heating recovery. Again energy saving light bulbs such as LED lighting contributed greatly to savings. It was found Absorption Chillers powered by Waste heat added to energy savings. Also efficient air conditioning systems such as variable refrigerant cooling systems contributed to savings. For water efficiency low-flow showerheads and kitchen sinks were a great contributor to savings as well as grey water systems. The study found the choice of floor slab material to be the key component to achieving the 20% carbon footprint savings. The ROI was less than 1 year when all of these different measures were employed for Hospitals in the different countries in the study.
  1. Light Industry:
    The most effective intervention in light industry structures were in the areas of water efficiency and air flow systems. Variable Frequency Drives in the Air Handling Units coupled with CO2 sensors for fresh air intake helped create efficiencies with the air flow systems. As with most other projects energy saving light bulbs such as LED lighting contributed also to savings. In cooler climates also the use of VRF cooling systems and Solar Hot water collectors contributed to energy savings. For water savings the use of efficient faucets equipped with aerators as well as rain water harvesting systems created the needed water savings to meet the EDGE requirements. As with all of the other building types the choice of floor slab was the greatest contributor to material savings. The ROI generally was less than 1 year when all of these measures were employed for light industry buildings in the different countries in the study.

In summary the study showed that a variety of measures contributes to savings in the areas of energy and water. Energy savings measures are of course dictated to some degree by whether you have a climate that has just warm or warm and cold weather. Heating and Cooling were mentioned as major factors in Homes, Hotels, Shopping Centers and Schools. Lighting was listed as a key contributor to savings except in Schools and Light Industry. Heat Recovery was found to be effective in Hospitals and Offices. For water Homes, Hotels, Schools, and Hospitals all found water efficient fixtures to be the main contributor to water savings. Grey water recovery was found to be useful in Hotels, Shopping Centers, and Hospitals. All categories focused on the Floor Slab for the savings in the materials area.

For more information about this study check out the following link on the EDGE software website: https://www.edgebuildings.com/technical/research/

 

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