The standards for eco-friendly building accreditation were newly revised in July 2010, providing several incentives such as reduction in local tax, easing of floor space index, relaxation of landscape architecture area, and easement of height limits f...
The standards for eco-friendly building accreditation were newly revised in July 2010, providing several incentives such as reduction in local tax, easing of floor space index, relaxation of landscape architecture area, and easement of height limits for buildings, for promoting eco-friendly accredited buildings.
The authors in this study analyzed items of construction cost added for eco-friendly accreditation from the existing research materials and interviews with designing companies and builders and calculated construction cost by each item by grades, centered on a project (apartment housing) located in Kyungki-do. The incomings were calculated by each item by grades from investigating and analyzing incentives based on acquiring eco-friendly accreditation.
This study is purported to analyze economics by comparison of incomings and outgoings based on eco-friendly building accreditation in a new project of apartment housing to support rapid decision-making on grades of eco-friendly building accreditation from the aspect of designers and builders at earlier phases of projects.
These findings are summarized as follows.
1) Selection and calculation of additional construction cost items
Items of construction cost related to eco-friendly building accreditation include land use, transportation, energy, materials & resources, water resource, prevention of environmental pollution, maintenance, ecological environment, and indoor environment, and this study calculated construction cost by construction sorts (architecture, engineering, mechanics, and electricity) by grades on energy, materials & resources, water resource, prevention of environmental pollution, ecological environment, items that were analyzed as main ones from the existing research materials and interviews with persons in charge. The results of construction cost calculation indicate that the cost on energy was applied highest, or between 60,220 and 152,000 won /(3.3M2). In this context, it may be efficient to enhance grades of eco-friendly building accreditation with relatively lower amount of money at construction by changing heat insulators, application of renewable energy, and using high-efficiency apparatus.
2) Selection and calculation of incomings items
Incomings items based on incentives include easing of floor space index, landscape architecture area, and height limits for buildings, and easing of floor space index was shown to be most effective. Calculation of incomings by grades is earnings with increasing installment area based on increase in floor space index. The results of this study showed that the best-first grade was highest, or 326,000 won/(3.3M2), for the rate of easing of the best-first grade was highest in incentive rate of easing of floor space index (12% or less for the best-first grade, 8% or less for the best-second and the excellent-first grade, and 4% or less for the excellent-second grade).
3) Analysis of economics based on case study of the subject site
While the best-first grade was higher both in outgoings and incomings in additional construction cost, the excellent-first grade was analyzed to have the highest economics because outgoings of construction cost was lower compared with incomings. Although the excellent-first and the best-second grade had the same incomings, the excellent-first grade was shown to have higher economics with lower outgoings from builders as the best-second grade had higher outgoings.
4) Further studies
The scope of this study is limited in analyzing economics from the aspect of builders (constructor), and further studies are needed to analyze economics of additional items such as tax reduction from the aspect of those who are going to reside in the buildings (users).