Abstract:
This research aims to study the greenhouse gas emissions and energy consumption in the residential
construction that has differences in house style, functional, area, construction methods and building
materials such as brick, lightweight concrete, precast concrete and half wood-half concrete house.
The activity data was collected from 42 samples which can be divided into three sizes: small (120180
m), medium (181-350 m2) and large (351-500 m2) including three different styles which are
contemporary style, modem style and Thai-modem style. The greenhouse gas emission in the unit
of kgCO2e 1m2 was calculated from three scopes: 1) the acquisition of construction materials
(Cradle-to-Gate.) of which the data came from transaction price and quantity of materials (Bill of
Quantities), 2) the construction process (Gate1-to-Gate2) and 3) the energy consumption during use
phase of the residential houses calculated by the EnergyPlus program. The results found that the
highest greenhouse gas emissions excluding the greenhouse emission during use phase was belong
to the precast house (237.51+-40.08 kgCO2e 1m2) followed by the brick house (215.61+-36.09
kgCO2e /m2), lightweight concrete house (194.65+-26.56 kgCO2e/m2) and half wood-half concrete
house (4.41+-36.91 kgCO2e/m2), respectively. Considering the size of the house (mixed house
models), the large house emitted greenhouse gas less than small and medium-size house. The
greenhouse gas emission from large house contributed 82.79+-94.14 kgCO2e/m2, while that from
small and medium-sized house contributed 133.24+-40.61 kgCO2e/m2 and 120.35+-55.15 kgCO2e
/m2. House style also plays an important role in greenhouse gas emission. It was found that the
modem house, Thai-modem and contemporary emitted 4.41+-36.41 kgCO2e/m2, 240.65+-82.86
2 kgCO2e/m and 253.09+-20.63 kgC02e /m2, respectively. Interestingly, 98 percentages of
greenhouse gas emissions sources came from building materials and only 2 percentages came from
construction processes. The differences of wall materials also affected the electricity consumption
during use phase of residential houses. The annual electricity consumed for air conditioner of the
houses made from lightweight concrete, hardwood, concrete and brick was 18.92 kWh/m2/y, 25.30
kWh/m2/y, 27.23 kWh/m2/y and 28.89 kWh/m2/y, respectively. Accordingly, the 25 years
greenhouse gas emissions during residential phase was emitted from lightweight concrete house
(798.45 kgC02e /m2), followed by concrete house (813.66 kgC02e /m2) and brick house (842.52kg
C02e /m2) and Thai-modem house (491.11 kgCO2e /m2) which is the least emission. There are
three alternatives to reduce energy consumption and greenhouse gas emission from residential
houses such as using alternative wall insulation which has low thermal mass and low heat storage,
increaing at least 1 DC for temperature setting of air conditioner and using alternative glass which
has low solar heat gain coefficient (SHGC). The best overall energy reduction and greenhouse gas
emissions from implementing these options were 995.75 kWhly and 558.62 kgCO2e /y.