Need updating rating system for LEED certification

LEED (Leadership in Energy and environmental Design) is an innovative certification system to evaluate the design, construction, operation, and maintenance of green buildings, homes and neighborhoods, especially for building energy usage. It gives quantifiable rating systems for the customers to know the level of building with variable categories. With the design view point, there are two basic categories to quantify the level of energy savings; active design and passive design. These two sustainable design methodologies should reflect the locational characteristics, however, there is lack of consideration in LEED certification.

Firstly, in a passive design viewpoint, surface area to volume (S/V) ratio should be considered differently according to building locations. ‘Passive design’ is the design that takes advantage of the climate to maintain a comfortable temperature range in the home. S/V ratio is one of the main methods to reduce building energy consumption by increasing heating efficiency. However, LEED have not been used in appropriate way; identical S/V ratio is used in different places. Building energy consumption is highly dependent on the weather status of the area. Therefore, the energy saving building design is closely related with the weather status of area. However, LEED rating on buildings in different area is applied in the same methodologies. For example, Seoul, South Korea which has a huge temperature difference between summer (24°F) and winter (84°F) has an identical S/V ratio of USA. To make better energy saving building, it is important to design lower S/V ratio buildings in Korea. On the contrary, S/V ratio in Seattle where the temperature between summer and winter is not significantly different does not necessarily have to be taken into too much consideration compared to those required in Seoul.

Secondly, in an active design viewpoint, energy generating systems such as Building-Integrated PhotoVoltaics (BIPV), Solar water heater, Rainwater harvesting are also considered differently according to building locations. For instance, total days with sun in Seattle area is 164 days per year[1], which includes the days when cloud covers up to 30% of the sky during daylight hours and thus, BIPV in Seattle has relatively low efficiency. Wild turbines frequently observed in urban area do not meet its energy demand because of its relatively slow wind velocity. On the contrary, shoreline area or mountain valleys where wind velocity is approximately more that 14m/sec high enough to satisfy the energy demand have higher efficiency in BIPV.

For these reasons, I think that LEED certification should be taken into more consideration with the reflection on the locational characteristics among different regions.

[1] http://www.currentresults.com/Weather/Washington/annual-days-of-sunshine.php

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About asiawideweb

Junyong, Jamie, An MUP & MSRE Candidate | Class of 2015 College of Built Environments University of Washington mobile_US : (206) 249-3855 / S. Korea : (010) 9698-2022 email: asiawideweb@gmail.com / jya2@uw.edu

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