In the recent decades, the reliance on fossil fuels has escalated significantly due to economic development and evolving lifestyles. Buildings have emerged as major energy consumers, contributing substantially to global energy demand, particularly through heating, ventilation, and air conditioning (HVAC) systems. The escalating energy prices and environmental concerns have intensified the search for renewable energy sources, particularly solar energy, which is abundant and sustainable. Active solar systems utilize external devices to harness solar power, while passive systems function independently of such devices. Passive solar systems present numerous advantages, including lower initial construction costs and minimal operating expenses. Their longevity often matches that of the building itself, making them an attractive option for enhancing energy efficiency in architecture and reducing overall life cycle costs. Key examples include natural ventilation for promoting airflow, shading devices like overhangs to mitigate heat gain, and thermal insulation for reducing heat transfer. High-performance glazing manages solar radiation, while green roofs and green walls improve insulation and air quality. Other strategies include optimizing building shape and orientation, using evaporative cooling, and incorporating phase change materials (PCM) for temperature stabilization. Additionally, Trombe walls capture solar heat, allowing these systems to significantly lower energy demands while ensuring occupant comfort. Life cycle assessment (LCA) is a critical tool for evaluating the environmental impacts of buildings throughout their entire lifespan, from raw material extraction to disposal. By quantifying energy use and emissions, LCA helps architects and builders make informed decisions that minimize environmental footprints. This assessment informs the selection of passive design strategies, which can significantly reduce operational costs. Life cycle costing (LCC) complements LCA by analyzing the total cost of ownership, including initial capital, maintenance, and energy expenses. It is essential for assessing the economic feasibility of passive systems, guiding investments in energy-efficient renovations. Understanding LCC allows building owners to identify cost-effective solutions that not only alleviate energy bills but also enhance sustainability, making it a vital consideration in modern construction practices. In this chapter, various passive solar systems will be explored to enhance building performance regarding energy efficiency and cost-effectiveness. The significance of LCC will be emphasized in assessing the economic benefits of these systems. A comprehensive review of the potential of passive design strategies will be provided, along with recommendations for the most suitable options based on their effectiveness. By comparing the life cycle costs of different passive systems, the most practical solutions for optimizing energy consumption and maximizing financial savings in building projects will be identified.