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
In addition, in historic districts, Landmarks
Preservation Commission review is required before permits are issued.
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 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
series of online resources to assist homeowners with window questions.
To contact NAPC, email firstname.lastname@example.org.
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Questions or Suggestions?