Below are frequently asked questions about windows.

Q: Should I replace my single-pane windows?

A: I do not recommend replacing single-pane windows with new dual-pane windows for energy savings alone. Replacing windows is expensive, and it can take years to receive a return on your investment. The majority of heat coming in through the glass in Phoenix is in the form of infrared energy — the heat contained in sunlight. Adding a layer of glass does very little to stop the sun's rays and associated heat. Instead of replacing your windows, try shading them with shade screens that block at least 80% of the sun's rays. Shade screens typically pay for themselves in one to two summers.

Q: Are new dual-pane windows cost effective?

A: Energy-efficient windows save energy, but a window replacement is unlikely to pay for itself in energy savings alone. If you need to replace your windows for other reasons, the premium you'll pay for high-performance windows (ENERGY STAR® or better) is generally worth the investment. And like so many other major energy efficiency projects, much of the energy savings depends on the quality of the contractor you hire to do the work. Bad installations not only can leak and cause drafts but also can lead to major moisture damage.

Q: We are having a home built here in Phoenix, and we are considering low-E windows. Do the savings in energy costs make it a worthwhile investment?

Low-E glass works by reflecting heat back to its source using an ultra-thin metallic coating on or in the glass. When selecting low-E windows, make sure they are rated as "low solar gain." This type of window is designed for the desert climate.