Proper selection and installation of window systems are vital considerations in renovating the building envelope. Along with providing key benefits of natural light and ventilation, window systems can play a significant role in reducing maintenance, improving comfort, and contributing to the building occupants’ health and safety.A functional and attractive window system enhances appearance, image, and comfort both inside and outside the building. For high-rise residential buildings and office complexes, this can lead to tenant loyalty through reduced turnover and even increased rental rates. It also can mean safer, cleaner interior environments.Following are three important questions to ask on window renovation.1. How can we reduce our building maintenance?Reducing time and materials associated with window maintenance saves costs and improves your bottom line.Specifying windows with integral Venetian blinds instantly omits the tedious task of cleaning the blinds. Newer windows also minimize hardware and weather stripping replacement. For aluminum windows, choosing a durable and permanent anodizing or baked-on fluoropolymer paint eliminates periodic repainting.Side-hinged in-swing windows and tilt sash double hung windows can be safely cleaned from the building interior, further reducing maintenance costs. Self-cleaning glass also represents an exciting, new development in the industry.2. How can we make our building more comfortable?In colder climates, windows should be double- or triple-glazed with thermal barrier frames and dual weather stripping. New airtight seals eliminate cold weather drafts, and higher interior surface temperatures enhance occupants’ radiative comfort.In warmer climates, choose solar control glass, integral blinds, and/or exterior sunshades. Modern, coated glass can offer low solar heat gain while maintaining optical clarity and maximizing the use of natural daylight. Aesthetically and psychologically pleasing, natural daylight reduces air-conditioning loads, thereby saving energy. Glare control also can be achieved through dark-coated glass.3. How can windows improve our building’s health and safety? In situations where water penetrates the building or condenses due to high interior humidity, unsanitary moisture can damage adjacent materials and promote mildew. Some mold growth has been associated with “sick building syndrome” and has prompted several personal injury claims, lawsuits, and even governmental investigations.Another timely topic is the safety and security of building occupants. Working with the window manufacturer, replacement window systems can be fabricated to integrate nearly any security system. Other glazing system features can include bullet- and blast-resistance, seismic performance requirements, or hurricane-resistant needs.Heather West (heatherwest@earthlink. net) focuses on building products, specialty contractors, and design services clients. Sources for this article include (aamanet.org) and (www.wausauwindow.com).