Wood Window Frame
A wood window frame is a framework around the glass of the window that provides support. It can be made from softwoods such as fir, pine, cedar, and spruce, or hardwoods such as oak, mahogany.
Look for windows made from locally sourced wood and with other energy efficiency features, such as multiple panes, argon-filled and Low-E coatings.
The insulating value of windows is usually rated by the whole window U-factor and the lower the value, the better. Energy Star rated windows should have a U-factor of 0.27 Btu/hr-sq ft °F or less for Northern climates.
Wood-framed windows can have low embodied energy and can be built with locally sourced woods. In northern American climates, red cedar, white pine, and oak can be sourced locally. Wood such as mahogany is often imported from humid, tropical environments for its excellent durability and weather resistance.
Typical wood windows require regular maintenance (paint or treatment). Aluminum or vinyl clad windows are also an option that reduces maintenance while extending the lifespan of the window. They still have less embodied energy than most other window frame options.
Early window frame materials included wood, iron, and lead. Of those, wood is still used today, and metal frames have graduated to aluminum, stainless steel, and coated steel, with insulation breaks to cut heat loss. Lead is no longer commonly used in window frames.