In Islamic republic of Iran, the heating and cooling of buildings account for approximately 40% of total energy use. From the entire energy loss taking place in a building, one third of that energy loss occurs through the windows. Many of today’s existing buildings are not energy efficient, and consume more energy than is needed in order to make the working and living environments comfortable. This is a very large waste of natural resources and money. With the recent energy crises and the rising price of energy, finding a way to lower the energy consumption of a building is very important. To decrease a building’s heat loss one may suggest limiting the amount of glass in a building, however windows are an excellent source of heat and light. Windows bring light, warmth, and beauty into buildings and give a feeling of openness and space to living areas. They can also be major sources of heat loss in the winter and heat gain in the summer. However, when properly selected and installed, windows can help minimize a home's heating, cooling, and lighting costs. By reducing the heating and cooling load of a building, the amount of energy that is needed to heat or cool the building is also reduced. Reducing heat loss or gain in homes often includes either improving existing windows or replacing them. This paper describes an option to energy-efficient windows available for reducing a home's heating and cooling energy requirements. When air leaks around windows, energy is wasted. Energy is also transferred through the centers, edges, and frames of windows. Eliminating or reducing these paths of heat flow can greatly improve the energy efficiency of windows and, ultimately, of homes. Several options are available to reduce air leaks around windows; the least expensive one is the proposed system. Traditionally, clear single glass has been the primary material available for window panes in homes. Lack of suitable strategy for minimizing energy waste from these windows and other openings is one of the major deficiencies in this field of study. In this article a simple solution for optimizing the energy consumption and also increasing the performance of common windows and other openings of a building is studied. This technique involves adding a second layer of glass along profiles as the coverage of prior frames. This method helps to prevent energy wasting from previously used materials and also provides more indoor thermal comfort on account of uniformity in environment temperature. Generally, such a process can simply be accomplished without extensive requirement to equipments with a minimum cost. The computer simulation program THERM 5.2 is used to predict the thermal behavior of the windows. Computer modeling shows a window's U-value reduction from 5.71W/m2k, to 3.71W/m2k, which consist 37% reduction in Thermal transmittance. Work is underway to define the application constraints and quantify the comfort benefits of such system. The further work is still required to incorporate the calculation routines into suitable models that will allow the consumers to make full use of this optimization method.