Sometimes there are compelling reasons not to replace old windows. Some old windows are beautiful, thoroughly appreciated, and repairable. Some are in historic homes, where the local ordinances prohibit replacing them. Or you may find the cost of window replacement too high, while other, less costly projects could save just as much energy. If you choose not to replace old windows, we recommend that you upgrade your windows to make them more airtight, and that you consider adding energy-efficient storm windows tailored to your home’s style.
Researchers in Colorado found it possible to improve the overall energy performance of a home’s historic, single-pane windows by a factor of 5 without altering their character. They accomplished this by repairing and air sealing the old windows, and then installing excellent storm windows with a fiberglass frame and a low-U IGU. This also made the house much more comfortable.
The Replacement Window Market: Making Informed Choices
In 2010, 41.5 million windows were shipped in the United States—over 71% of them destined for the remodeling and replacement market. Researchers project that this market will reach 36.1 million windows by 2014, and that over 60% of these windows will have vinyl frames.
This growing market leads to fierce competition among manufacturers and retailers, who employ a variety of sales techniques to attract business. These range from newspaper, radio, and TV advertising to e-mails offering “advice” on replacement windows (whose real aim is to sign up homeowners for a home visit by a high-pressure salesman). Home shows aimed at the remodeling market are peppered with purveyors of windows, doors, and skylights.
All of this can be useful, but it’s critical to be an informed consumer:
Think of a skylight as a window in the roof. Some skylights can be opened for ventilation or for an emergency exit. Like windows, skylights have a range of U-factors, SHGCs, and VTs—all of which affect their function and their cost. Some skylights include roller-style shades, effectively lowering both SHGC and VT. The most effective shades for this purpose are installed on the outside of the skylight; these intercept sunlight before it penetrates the home’s conditioned envelope.
In general, skylights add natural light and a level of charm to the home and can replace electric lighting by day. However, it is important to install only high-quality skylights, with thermal and optical characteristics appropriate for the climate zone. Install them carefully, to avoid water leaks and thermal loss. Moderation in the use of skylights is generally a virtue.
Two kinds of skylight are commonly used in residential structures. These are conventional skylights and tubular skylights (also known as light tubes, sun pipes, or solar tubes). Their small diameter makes it possible to install tubular skylights without cutting the roof framing members, and they don’t cause as much heat gain or loss as larger skylights. This is important in hot or cold climates, because skylights can lose more heat in winter than a window, and are harder to shade in summer.