Abstract- In this work the sequential search optimization method applied to a 430  three-floor residential building to find optimal building envelope and solar technology options along the path to zero energy building design. Five different climates of Iran including: Tehran, Tabriz, Esfahan, Bandar Abbas and Shiraz, which are almost good representative of Iran’s climate, are considered. Optimal design options for each climate suggested for different design cases including minimum energy related cost and maximum energy saving design options. It is shown that a proper combination of envelope and solar options can lead to a sustainable design in terms of energy use and environmental effects with an affordable cost. Optimization results showed that at the min-cost design option, it is possible to minimize energy cost up to 23% while energy saving increases up to 15% depending on the considered climate. Maximum energy saving up to 49% is reported while energy cost rises to 25% in comparison to reference building. Depending on each climate, different envelope and solar options are suggested which can be used as a practical guideline for energy management companies and architects in early design stages of building envelope. Investigating the optimization results toward zero energy building design reveals that before using solar technologies to produce a home's energy, it is more cost-effective to first reduce energy usage of building using sustainable envelope parameters which results in a less expensive PV or solar heat water (SHW) system.