© 2023 Green Window Restoration

    The repair of historic windows is not only a financially smart move and better for our environment, but it is almost always the right choice.

Before any decisions are made about replacing historic wood windows, consider the benefits of retaining existing windows:

  • Wood windows made prior to the 1940s are likely made from old-growth wood. This wood is significantly denser, durable, rot-resistant, and dimensionally stable. New wood windows, while preferable to new vinyl or composite windows, still do not match the quality and durability of historic wood windows.  

  • Historic windows were made specifically to fit their window openings and were custom installed. Each one is probably a little bit different. Older windows may also have shifted and changed with their openings as the building aged. After 100 plus years, they may no longer be exactly square, but they still fit the opening. New, theoretically square replacement windows installed in those not-perfectly square openings will leave drafty gaps.

  • Traditional windows are made from individual parts. Each piece can be individually repaired or replaced in kind. Vinyl, aluminum, fiberglass, and composite windows are manufactured as a unit and the components generally cannot be repaired. When a part fails, the entire unit will need to be replaced. 

  • Adding weather stripping and an interior or exterior storm window to a historic wood window in good repair will significantly improve its energy efficiency and the occupants’ comfort level without having to replace the entire unit.

  • Whenever possible original wood windows should be repaired rather than replaced. Permanent repair of a window may be less expensive than wholesale replacement. It is also possible to bring original windows up to modern environmental standards without harming any features of historical value. A recent British survey indicated that, on average, only 5% of timber in windows that were being replaced was affected by decay. Yet a 1991 Gallup Poll revealed that 46% of homeowners replaced wood windows because of 'rotten timber', and only 20% to reduce drafts and heating bills.

  • Windows are an authentic part of a building - they are a character-defining feature. Their size, placement, proportional relationship to the wall space, style, material, how light reflects off of them - all of these elements contribute to how a building looks and feels. Vinyl windows on a historic house will never look right. Compare the look of the vinyl replacements on the right to the charming original wood windows on the left:

  • Going green is more than just energy performance. To determine the real environmental impacts, one must take into account the embodied energy of the existing windows and that of the new window, the environmental impacts of manufacturing new products, and the expected life-cycle of the product. Embodied energy includes the energy required to extract the raw materials, transport them, make them into a new product, ship the product and install it. Tearing out historic windows for replacement units not only wastes their embodied energy, but additional energy is required to remove and dispose of them. This is on top of the energy required to create and install the new windows.

  • Read the fine print. Many replacement windows also come with “limited lifetime warranties",  Replacement windows are called “replacement” for a reason. “Lifetime” better describes the lifetime of the product, not the lifetime of the building since research indicates that 30% of the time, a replacement window will be replaced within 10 years.

  • Installing new windows is not going to pay for itself in energy savings. Statistically, it is virtually impossible to recoup, in energy savings, the amount of money spent on replacing historic wood windows with new windows before the new windows need to be replaced. It can take upwards of 40 years to recoup in energy savings what was spent to replace the windows, Furthermore, the typical replacement window often fails within about 20 years. In other words, in the time it would take to recoup the cost of the original replacement windows, statistically, the replacement windows will already have had to be replaced at least once. 


    In summary, there are no inherent defects in the original design of the wood window, an extremely sophisticated piece of technology that has lasted, with minor modifications, for 350 years. It is also quite feasible to apply modern repair and maintenance techniques to our existing wood windows, making them sustainable, green and energy-efficient for decades more to come.