根据美国能源部（DOE）的数据，建筑约占美国所有能源消耗的40%。因此，提高建筑的能源效率应该成为建筑业主、设计专业人士、公用事业公司、政府机构和相关行业的首要任务。这些不同的组织不仅致力于建造高效的新建筑，还通过能源改造改善老化性能。大多数商业建筑的能源改造都集中在安装高效锅炉、电机和照明设备上。 然而，根据美国环境保护署（U.s.Environmental Protection Agency）的数据，由于窗户效率低下，导致居住者感到不适，从而抵消了设备带来的效率提升。在寒冷气候下，窗户的不适占典型建筑热负荷的25%，在温暖气候下占冷负荷的50%。由于设备的尺寸是为了满足特定建筑的需求，因此应首先解决改善建筑围护结构的问题，以便指定更小的设备，从而节省前期和持续成本。改善现有商用玻璃系统的能源性能有多种选择，包括: 内窗贴膜的应用——主要解决太阳能热增量问题——完整的窗户拆除和更换——解决太阳能热增量问题和改进的U-Factorier室内商业风暴窗问题——主要解决改进的U-Factorier室内安装的Low-E改装中空玻璃装置问题——解决太阳能热增量问题和改进的U-Factorier替代方案具有特定性能好处以及相关的成本和便利性影响。对于大多数性能较低的单层玻璃商业建筑来说，太阳能热增益是一个主要问题，无论气候区域如何。 这导致冷负荷增加、暖通空调设备尺寸增大、能源成本增加和居住舒适度降低。玻璃系统的任何改进都应采用技术，通过使用高性能low-e涂层来减少太阳能热增益的影响。同时，对于供暖占主导地位的气候区，U系数的大幅降低会同时降低暖通空调的供暖需求，降低能源成本，提高居住舒适度。本文旨在比较一个案例研究改装与预调试改装的性能效益和成本影响- 现有的单片玻璃系统。引用:2016年年度会议，密苏里州圣路易斯，会议论文

Buildings account for roughly 40 percent of all energy consumption in the United States, according to the U.S. Department of Energy (DOE). As a result, improving the energy efficiency of buildings should be a top priority for building owners, design professionals, utility companies, governmental bodies and allied industries. These diverse groups are working not just to build efficient new construction, but also to improve aging properties through energy retrofits.Most energy retrofits for commercial buildings focus on installing high-efficiency boilers, motors, and lighting. However, efficiency gains from equipment can be offset by occupant discomfort due to inefficient windows, which can account for 25 percent of a typical building's heating load in cold climates and 50 percent of the cooling load in warm climates, according to the U.S. Environmental Protection Agency. Because equipment is sized to service a specific building's needs, improving a building's envelope should be addressed first, so that smaller equipment can be specified, saving on the upfront and ongoing costs.A variety of options exist for improving the energy performance of existing commercial glazing systems including:Application of interior window films – primarily addresses solar heat gainComplete window rip-out and replacement – addresses both solar heat gain and improved U-factorInterior commercial storm windows - primarily addresses improved U-factorInterior installed Low-E retrofit insulating glass unit - addresses both solar heat gain and improved U-factorEach alternative has specific performance benefits and associated cost and convenience implications. Solar heat gain is a primary problem with most commercial buildings having lower performance, single-glazing, regardless of climate zone. This leads to increased cooling loads, larger sizing of HVAC equipment, higher energy costs and lower occupancy comfort levels. Any improvement in the glazing system should incorporate technology to reduce the impact of solar heat gain through the use of high performance low-e coatings. Concurrently for heating dominant climate zones, a substantial reduction in U-factor acts in parallel to reduce HVAC demand for heating, reduces energy costs and improve occupancy comfort levels.This paper is intended to compare the performance benefits and cost implications of a case study retrofit relative to a pre-existing monolithically glazed system.