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There is a misconception in Denver's historic neighborhoods that original wood windows need to be replaced to be energy efficient and that replacement will increase the value of a home. Though old double-hung windows or casements may not operate as smoothly as they did when they were new, restoration is in many ways a far better alternative to replacement. Windows are a key architectural detail of a home, and help define its visual character. The Technical Services Center of the Department of the Interior, Historic
Denver, Inc., the Denver Landmark Preservation Commission, and most Historic Preservation professionals recommend the retention and repair of original windows whenever possible. In the case of Denver Landmarks and districts, original windows CANNOT be replaced without permission from the Landmark Commission staff. The bonus is that there are tax credits available for a restoration project. Denver Landmark Commission staff can be reached at
720-865-2942 for more information.

The repair and weatherproofing of existing wooden windows is more practical than most people realize. Many windows are unfortunately replaced because of a lack of awareness of techniques for evaluation, repair, and weatherproofing. Wooden windows, repaired and properly maintained, will have greatly extended service lives while contributing to the historic character of the building. Thus, an important element of a building's significance will be preserved for the future.

With contemporary wood restoration techniques, many window components can be saved, and in this way eliminate the need for replacement. Under certain circumstances, restoration may prove to be the much more cost effective and less intrusive solution. For example, if only one or two windows in a home require extensive repair, then some careful restoration work might help assure that the home's windows remain similar without replacing them all.

Energy efficiency, operability and the security of an existing window may all be improved by a number of historically and aesthetically acceptable means. But to focus on energy upgrades, one may begin with proper weatherstripping, which serves as the primary control of heat loss through a window. Other options include high quality storm windows, perhaps those with wood frames and interchangeable glass and screen panels. Edge detailing can make these storms look traditional while greatly improving energy performance, protecting the original sashes from the effects of direct contact with the weather, and eliminating condensation issues.

Interior window treatments (storms, special blinds and coverings) are also an option for energy conservation, while perhaps resolving issues of noise control or privacy. Yet other means include the use of insulating glass units, jambliners, or insulating techniques, but it is important to know that these systems may significantly alter the appearance of the window and be more expensive to repair in the event something breaks.

Although the retention of original or existing windows is always desirable and this article is intended to encourage that goal, there is
a point when the condition of a window may clearly indicate replacement. The decision process for selecting replacement windows should not begin with a survey of contemporary window products that are available as replacements, but rather begin with a look at the windows that are being replaced. Attempt to understand
the contribution of the window(s )to the appearance of the facade including:

1. the pattern of the openings and their size;
2. proportions of the frame and sash;
3. configuration of window panes;
4. muntin profiles;
5. type of wood;
6. paint color;
7. characteristics of the glass;and
8. associated details such as arched tops, hoods, or
   other decorative elements. Develop an understanding of how the window reflects the period, style, or regional characteristics of the building, or represents technological development. Landmark Commission and Historic Denver Staff can help you determine the style of your windows.

Armed with an awareness of the significance of the existing window, begin to search for a replacement that retains as much of the character of the original window as possible. There are many sources of suitable new windows, from production companies to shops that can replicate every detail. As a matter of accurate comparison, however, be as precise as possible when requesting proposals for these products and services. Call Historic Denver's Urban Living Program at 303-534-5288 x 16 for suggested suppliers and restoration specialists.

Generally, be aware that the decisions a property owner makes with regard to window improvements nearly always involve trade- offs. New window operating systems, while allowing for easy cleaning and sash removal, can be much more complex and proprietary (hence more expensive to repair) than the old. Their warranties can be disturbingly short, while properly restored and maintained vintage windows could conceivably last a lifetime. And even though historic windows may require more maintenance, they can also lend a level of detail and character unmatched by today's production models.