Replacing Windows in a Historic Home or Historic District

Listing on the National Register of Historic Places does not, by itself, stop a private owner from replacing windows; a local historic district or landmark ordinance is what can require approval first. Where approval is needed, reviewers look for repair before replacement, and for a close match when replacement is justified.

National Register listing versus local designation

National Register listing does not restrict a private owner; local designation is what brings design review. The two programs are separate.

• National Register listing. The National Park Service (NPS) says that under federal law, listing places no restrictions on what a non-federal owner may do with the property, up to and including destruction. The exception is a project that involves federal assistance, usually funding or a federal license or permit.
• State and local law. NPS adds that state or local preservation laws may apply, and recommends contacting the State Historic Preservation Office (SHPO) before acting on a listed property.
• Local designation. Cities and counties create local historic districts and landmarks by ordinance, with their own review. North Carolina’s preservation office, for example, explains that owners of local landmarks and of property in local historic districts must obtain a certificate of appropriateness from the preservation commission before making significant changes.
• No automatic link. Under NPS rules for the Certified Local Government program, a participating local government may not subject a property to local design review automatically and solely because it is listed in the National Register. A house can be in a National Register district without being in a local district, and the reverse.

The first step, then, is a question for the city or county planning office: is this address in a local historic district or a designated landmark, and does the ordinance cover windows?

How reviewers look at historic windows

Federal guidance starts from the Secretary of the Interior’s Standards for Rehabilitation. NPS applies them directly to federal tax credit projects, and North Carolina’s office notes that local design guidelines and the federal standards usually agree. Local commissions still write their own guidelines, so the local document governs.

Standard 6 is the core of window review: “Deteriorated historic features shall be repaired rather than replaced. Where the severity of deterioration requires replacement of a distinctive feature, the new feature shall match the old in design, color, texture, and other visual qualities and, where possible, materials.”

NPS’s guidance on evaluating windows adds several working rules:

• Repair comes first. It can include renewing finishes, epoxy repairs, replacing component parts, and adding weatherstripping.
• Condition must be documented. At a minimum, enough good-quality photographs to show the full range of conditions. A sample repair often settles whether repair is practical.
• Importance matters. The more important the elevation or space the windows belong to, the more important it is to keep them. Windows that are distinctive features count for more than simple manufactured units.
• Other reasons weigh in only alongside deterioration. Operation, hazardous materials, code requirements and energy performance, taken individually, are not reasons to replace. They may be considered together with deterioration.
• Some exceptions exist. Replacing a few windows for a need such as egress may be acceptable regardless of condition if it barely changes the building’s appearance. Where codes mandate impact resistance for severe weather, replacement may not depend on documenting deterioration at all.

The energy argument, with numbers

The Park Service’s position is that energy performance, taken alone, is not a reason to replace historic windows, because they can be made thermally efficient in other ways. Its 1981 Preservation Brief 9, citing 1977 ASHRAE figures, gives these heat-transfer values (U-values, where lower is better):

• Single-glazed wood windows: 0.88 to 0.99.
• The same windows with a storm window added: 0.44 to 0.49.
• A double-glazed metal window without thermal breaks: about 0.6.

NPS’s current guidance says the energy performance of historic windows can be significantly improved by adding storm windows and weatherstripping, or by replacing the glazing or the sash.

ENERGY STAR lists homes in historic preservation districts among those for which its certified low-e storm windows are an option where full replacement may be difficult. It adds one condition: check that the district’s requirements allow storm windows.

Tax credits: who qualifies

The federal historic rehabilitation tax credit is 20 percent, but it does not cover a private home. NPS’s eligibility rules state that the building must be depreciable after rehabilitation, meaning used for business, commercial or other income-producing purposes, for at least five years. They add plainly: “Owner-occupied residential properties do not qualify for the federal rehabilitation tax credit.”

NPS notes one partial exception. If part of a personal residence is used for business, such as an office or a rental apartment, rehabilitation spending on that part may in some cases be eligible.

Some states run their own programs. North Carolina’s preservation office, for instance, describes state credits for both income-producing and non-income-producing historic properties. The state historic preservation office is the place to ask.

Lead paint in older windows

Windows in a house built before 1978 may carry lead-based paint, and EPA estimates that 87 percent of homes built before 1940 have some. For any pre-1978 home, EPA’s first option is to assume lead-based paint is present and take precautions; the second is testing by a certified inspector or risk assessor. EPA’s Renovation, Repair and Painting Rule is not limited to replacement: it applies to paid renovation, repair and painting jobs that disturb old paint in a pre-1978 home, and to every firm doing them, down to sole proprietors, which includes a small shop hired to restore sashes.

When to bring in a professional, and what to ask

Start with the local preservation office, which confirms whether approval is needed, then bring in a contractor experienced with old windows who can document their condition. Confirm the property’s status before signing anything.

Questions for the preservation office or commission:

• Is this property in a local historic district or a designated landmark, and do window changes need a certificate of appropriateness?
• Which elevations are reviewed? Are rear or secondary windows treated differently from street-facing ones?
• What documentation do you need: photographs, window-by-window condition notes, drawings of the replacement?
• Are storm windows allowed, and in what finish?

Questions for a contractor:

• Will you survey each window and say which can be repaired, which need new sashes, and which need full replacement, with reasons?
• For any replacement, how will the new unit match the old in muntin profile, glass, frame dimensions and material?
• Can you do a sample repair on one window before the full job is quoted?
• Is your firm certified under EPA’s or the state’s lead renovation rule?

Keep copies of the approval and the condition photos. They are the record a future owner or reviewer will ask for.