historic preservation

resources for homeowners:  windows 

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Windows are one of the most common remodels on historic homes, and also are one of the most significant architectural elements of most houses. There are many misconceptions about window repair and replacement for historic houses – what is appropriate, what is cost-effective, and what the options are. 

The first, most important thing to remember is your objective.  Is it to cut down on energy costs?  Is it to be environmentally responsible?  Is it because your old windows are in disrepair?

Beware advertisements that claim great cost savings, as well as "free energy audits" from installation companies.  While there are many reputable companies out there, it is important to consider whether the business perspective represents your interests.  Remember, window installation companies are just that:  installers, not manufacturers or restoration specialists.

Also, note that window installations in the City of Tacoma require building permits under the International Residential Code 2006.  Window companies that tell their clients that no permit is required are incorrect (see Finding Contractors and Trades).  

In addition, in historic districts, Landmarks Preservation Commission review is required before permits are issued.

Window Types

Double and single hung wood sash windows are the principal historic window type in the district. Casement and awning wood windows are also prevalent. In all cases, original functional wood windows should be retained where possible, especially leaded panes. Original windows being retrofitted should be replaced with in-kind windows. 

Windows are an important element within the façade and can greatly enhance, or detract from, the proper scale. Therefore, it is inadvisable to change the shape or size of window openings, unless you are able to preserve the proper scale.

Repair Before Replace

The following is the order of decreasing acceptability for window restoration: 1) original window restoration, 2) restoration with new thermal or laminated glass retrofitted into original sashes, 3) retrofit wood sashes into original window frames with replica lead striping and mullions, 4) total window replacement with restoration quality wood windows, 5) clad wood windows in original size and configuration.

Vinyl Windows?

Vinyl windows are not acceptable for use in the Historic District, except under special circumstances, such as for new construction and in cases where the original windows are missing and were replaced with inappropriate windows, such as aluminum sliding windows or picture windows. Trim, detail and profile are the most important aspects of replacement windows—generally vinyl windows appear flat and lacking relief. This can be remedied with the use of trim and careful product selection.

Thermal Retrofitting, Sustainability and Energy Efficiency

Energy efficiency is an important consideration.  However, most people do not realize that window replacement is one of the least cost-effective solutions to high energy bills.  Simply adding a storm window to a properly weather stripped and sealed single pane window will have a payback period of less than 10 years; the payback period for replacement windows can be up to 200 years!  There is significant evidence that original wood windows with storm sashes perform similarly to modern thermal pane windows.

Retaining and restoring original wood windows also is environmentally-friendly.  Not only are restored windows, which are generally made of nonrenewable old growth timber, saved from the landfill, but restoring an original window also means that one less new window will have to be manufactured.

What Do the Experts Say?

Saving Windows, Saving Money:  Evaluating the Energy Performance of Window Replacement and Retrofit
A report produced by the Preservation Green Lab, a project of the National Trust for Historic Preservation, offers insight for homeowners weighing the financial and energy tradeoffs between replacing or repairing older, less efficient windows. This analysis, Saving Windows, Saving Money: Evaluating the Energy Performance of Window Retrofit and Replacement, builds on previous research by examining multiple window improvement options, comparing them to replacement windows across multiple climate regions.

The National Alliance of Preservation Commissions (NAPC) has assembled a series of online resources to assist homeowners with window questions.  To contact NAPC, email napc@uga.edu.  

Why Should I Repair or Restore My Old Windows?
Popular Window Replacement Myths
Of Paint and Windows - Repair or Replace?
Essential Online Window Articles
Wood Window / Replacement Window Energy Analysis

Questions or Suggestions?

Email landmarks@cityoftacoma.org.