In this work, a detailed investigation is carried out to evaluate the effects of using sunspace on heating energy consumption of a rural house by considering utilized sunspace glazing type, the filling gas type and the gas layer thickness. In the first part of the study, the effect of a sunspace on the energy consumption of a typical rural building located in a severe cold region of China is investigated. The results showed that the sunspace having single pane reduces the energy consumption by about 4.6% with respect to the reference building considering the coldest month, January. In addition, sunspace with double glazed unit is investigated and compared with the singleglazed. It is observed that a larger amount of energy (11.3%) is saved compared to the reference building in January, and the optimum air layer thickness of double glazed sunspace is determined as 12 mm. In the second part, different filling gasses (air, argon and krypton) are taken into account to optimize the gas layer thickness with respect to filling gas. It is found that the thickness of gas layer resulting in the minimum energy consumption significantly depends on the type of filling gas. The optimum gas layer thickness values are found as 12, 15 and 9 mm for air, argon and krypton, respectively. It is concluded that the sunspace with 9 mm thickness of double glazed unit filled with krypton can be suggested for the highest energy saving. Also, the results revealed the importance of comprehensive analyses on sunspaces regarding various parameters.