| Title |
Optimization Strategies for Window Performance Improvements under Government Funding in Low-Rise Residential Buildings |
| Authors |
진혜선(Jin, Hye-Sun) ; 김예원(Kim, Ye-Weon) ; 유기형(Yu, Ki-Hyung) ; 구보경(Koo, Bo-Kyoung) |
| DOI |
https://doi.org/10.5659/JAIK.2026.42.3.261 |
| Keywords |
Low-rise dwellings; Window grade; Energy demand; Energy consumption; ECO2-OD |
| Abstract |
This study quantifies the effects of window grade, window-to-wall ratio (WWR), unit location, floor-area group, and construction vintage on
heating performance in low-rise dwellings, including single-detached, multi-family, and row houses. Using ECO2-OD under identical climate
and internal conditions, 936 scenarios were modeled. Envelope thermal transmittance values followed building code revisions by year, and
windows were assigned grade-specific thermal transmittance and solar heat gain coefficient values. Heating energy demand and energy
consumption were compared across all variables using kilowatt-hours per square meter per year as the evaluation metric. The results show
that upgrading windows from the baseline to higher grades yields significant energy savings, while additional improvements between adjacent
upper grades are relatively small. In multi-family and row houses, unit location has the greatest influence on heating performance, particularly
for top, bottom, and middle units. Increasing the window-to-wall ratio from 15 percent to 25 percent reduces heating demand in
heating-dominated climates due to net winter solar gains. Larger floor areas also lower energy indicators per unit area by reducing the
surface-to-volume ratio. From a practical perspective, improving vertical thermal boundaries such as roofs and floors and optimizing window
design, including window-to-wall ratio and shading, should be prioritized over marginal upgrades among the highest window grades. Selecting
the top window grade is most effective when the cost per unit of energy savings is favorable. |