Mark Twain once said, "The coldest winter I ever saw was the summer I spent in San Francisco." No other remark so fully characterizes the meteorological schizophrenia so unique to the San Francisco Bay Area. It might be sunny in Noe Valley, while thoroughly damp and miserable in the Outer Sunset. A few miles outside of the official city limits, weather varies dramatically to the north, east and south bays. San Francisco itself hosts divergent microclimates that not only affect the moods of its residents, but wear heavily on the homes they live in. Depending upon existing window styles and designs, San Franciscans have a lot to consider in finding suitable replacements.

Whether they live in historical Victorian flats or in ranch style homes of the 50s and 60s, San Franciscans rely on their windows to cut dampness and fog in summer and bone-chilling wind in the winter. Residents of interior bay communities can face weeks of scorching heat in the summer. Almost everyone relies on their windows to provide security, reduce noise pollution and retain heat or air conditioning.

If you're looking for new custom or replacement windows, you should shop by type and style. Standard window designs that you'll discover throughout the Bay Area include bow windows, bay windows, garden windows, awning windows, casement windows, radius windows, picture windows and double-slider windows. In newer homes, you'll also see single or double-hung windows or thermally-improved custom aluminum windows.

Bow and bay window designs are common in the greater city area. They create the illusion of a larger interior to any room, but you have a lot of glass to replace. Casement windows and slider style windows are popular choices for modern dwellings for their relative low maintenance and ease of ventilation.

Perhaps the most important consideration lies in employing energy-efficient, double-pane windows wherever possible. Depending upon window design, your materials can include wood, vinyl, steel, aluminum and fiberglass. Because of the Bay Area's damp weather, your home may have a proclivity to wood rot and mold. The Efficient Windows Collective reports that a double paned high-solar-gain, low-e, argon/krypton gas-insulated vinyl or fiberglass window can really keep the wet outside and dryness indoors. Plus, the savings can be appreciable. Compared with a single-glazed wood or vinyl (or composite) window style, the newer energy efficient window can save you more than $100 a month in heating costs. San Franciscans are known for tenacity and innovation. You should shop for a window that combines style and efficiency.