Energy Performance of Detached House Building Envelope: Financial Investment Perspective

Abstract

This research aims to study the financial feasibility of designing an energy-saving building envelope, according to Thailand Energy and Environment Assessment Method (TEEAM). First, the author studies Thailand’s energy-saving assessment frameworks and compare assessment categories and rating scores. The results present that the building envelope category is the category with the highest proportion of score in all assessment frameworks. The scoring in the building envelopes category accounts for 23-40% of the total score (approximately 60-88% achieving a minimum tier). This study focus on TEEAM (R-49.02) as an energy-saving assessment and the design of glazing type, exterior materials, and ceiling insulation materials are examined in the sample house. Second, this study examined the cooling energy-saving performance of 29 building envelopes via using energy simulation program (eQUEST v3.64). The results classified saving performance into 4 classes. Finally, the result of energy-saving costs is analyzed compared to an increase in construction costs. To consider the feasibility of financial with 3 indexes, Net Present Value (NPV), Internal Rate of Return (IRR), and Payback Period (PB). The low-efficiency class contributes to 8% energy savings, while construction costs increase by 5%, which provides the IRR at 21%, NPV of 12,130 baht, and PB less than 5 years.