Doors and windows can have a major impact on the overall appearance of any building. Double-hung windows with divided lites and 6 panel doors may not be appropriate for a modern style home. Casement windows and flush doors are not typically used in colonial designs. Besides matching window and door styles with the architecture of the building, you should also consider exterior finishes and color schemes before you make a purchase. Aluminum or vinyl clad wood windows may provide a low maintenance exterior, but they are not meant to be painted. Making your finish selections at the same time you decide on windows and doors will allow you the greatest number of options.

Depending upon the size and style of house, windows and doors can represent anywhere between 4 and 10 percent of the total construction budget of a new home or addition. You should also keep in mind that they will have a major impact on the overall energy efficiency of the structure in which they are installed. As one of the major sources of heat loss or gain in a building, windows and doors will continue to cost you money for as long as you live in your home. The initial purchase price of a well sealed, high efficiency, "top-of-the-line" window or door unit will probably be more than a "builder grade" or "production" unit. However, over the long term, "inexpensive" windows and doors might end up costing you much more in higher energy costs than "more expensive" units. With the cost of energy continually on the rise, be sure to choose your new windows and doors wisely.

Window & Door Research

Efficient Windows Collaborative - EWC - "provides unbiased information on the benefits of energy-efficient windows, descriptions of how they work, and recommendations for their selection and use."

Windows and Daylighting Group, Lawrence Berkeley National Laboratory - information about glazing materials, advanced window systems, window properties, daylighting and performance, and several free software programs, including RESFEN, WINDOW, THERM and Optics

Florida Solar Energy Center - This institute is located at the University of Central Florida (UCF). It's mission is "to research and develop energy technologies that enhance Florida's economy and environment, and to educate the public, students and practitioners on the results of the research." Specific areas of study include; photovoltaic systems, solar thermal systems, energy-efficient buildings, windows and daylighting, air quality, simulation model development, and other energy related research.

Fenestration Research Group at the Florida Solar Energy Center - One of the many energy related programs at the Florida Solar Energy Center, the Fenestration Research Group "studies the energy and illumination performance of fenestration systems. The main focus is on solar heat gain and its effects on the thermal performance of buildings and energy costs for heating and cooling."

National Fenestration Rating Council - NFRC - "a non-profit, public/private organization created by the window, door and skylight industry." They have established a voluntary energy performance rating system for window, door and skylight products.

Selecting Windows for Energy Efficiency - a comprehensive article, on the Berkeley Labs site, from Home Energy Magazine Online dealing with insulation value, U-Factors, preventing condensation, window orientation and solar control, window labels, ventilation and airtightness.

What is a window U-Factor? - the U-factor measures how well a product prevents heat from escaping, which is the inverse of the insulating value or R-Factor.

How Do I Find the SHGC for my Windows? - detailed instructions for finding the Solar Heat Gain Coefficient (SHGC) for your window, which should be found on the National Fenestration Rating Council (NFRC) label.

The Repair of Historic Wooden Windows - National Park Service, Preservation Brief by John H. Myers

The Repair and Thermal Upgrading of Historic Steel Windows - National Park Service, Preservation Brief 13 by Sharon C. Park, AIA

The Preservation and Repair of Historic Stained and Leaded Glass - National Park Service, Preservation Brief 33 by Neal A. Vogel and Rolf Achilles

Window, Door & Skylight Manufacturers

Andersen Windows and Patio Doors - One of the best known production window companies now has a site worthy of their reputation. This well designed Web site has plenty of easy to access product information.

Hy-Lite Block Windows - decorative glass block has been around for years, but building a weatherproof window frame in which to install them has always created some problems. Hy-Lite windows are made from acrylic blocks, not glass, and they arrive completely assembled in aluminum or vinyl frames that are easy to install and maintain - a great idea!

JELD-WEN Doors and Windows - One of the world's largest manufacturers of doors, windows, millwork and specialty wood products. Over the years, their window companies/product lines have included Caradco®, Norco®, Pozzi®, Summit®, and Wenco®.

Kolbe & Kolbe - Founded in 1946 by brothers Herb and Ervin Kolbe, Kolbe Windows & Doors continues to be a family business. They specialize in premium windows, including contemporary aluminum exteriors, as well as, a line of wood exterior and interior windows suitable for historical renovations.

Marvin Windows and Doors - Long known for their custom wood windows, Marvin also has 11,000 standard sized windows and doors. They are one of only a few manufacturers still producing authentic divided lites.

Pease Industries, Inc. - Manufacturers of fiberglass, steel, and their new carbon clad doors and door systems. Their products include Ever-Strait Fiberglass, Ever-Straight Steel, Pease Carbon, Homestead, and Homestead Eight-Foot high door systems.

Pella® Windows and Doors - Pella has long been known for producing high end windows with optional between-the-glass blinds. However, like most window manufacturers, they now produce several lines of windows in order to be able to sell their products to a larger market. Their ProLine® brand of windows and doors is a less expensive builder's grade, which is available in home improvement centers and lumber yards.

Therma-Tru Doors - Manufacturers of fiberglass door systems, as well as steel door systems, Therma-Tru was one of the first companies to market an insulated door with a fiberglass coating. Their products include Classic-Craft® and Fiber-Classic® fiberglass door systems, which feature a lifetime limited warranty.

Velux - Manufacturers of skylights, roof windows, and solar energy panels, which heat domestic water and resemble their standard roof windows.

Window & Door Trade Associations

American Solar Energy Society

Fenestration Canada - Formerly, the Canadian Window & Door Manufacturers Association (CWDMA)

Steel Door Institute

Association of Millwork Distributors - formerly the National Sash & Door Jobbers Association (NSDJA)

Window & Door Manufacturers Association (WDMA)