Scope of this study is, to examine the impacts of improvements made on building envelope and roof on existing buildings, to evaluate the waste gas emissions caused by the construction properties and energy consumption types of existing buildings. Calculations are done by creating model building that represents all existing building of which has 7.8, m height, 156 m(2) floor area, 3 stored and wooden framed single-glazed window system. Heating and cooling periods are taken up separately in different degree-day sections and optimum insulation thicknesses are obtained between 6 cm and 16 cm. Heating-cooling period of model building is 7 months-5 months for 1st DD section, 8 months-3 months for 2nd DD section, 10 months-2 months for 3th DD section and heating period is 10 months, no cooling period for 4th DD section. It is adopted that heating load is satisfied by natural gas, fuel-oil and coal and cooling load by electricity. Emission saving values which are dependent to fuel type and heating cooling period are determined between 28 % and 80 % for CO2, 58 % and 80 % for SO2 emissions. Results show that, dealing heating and cooling periods together in the analysis, produce effective solutions in order to ensure comfort conditions.