Solar energy for historic buildings

This story appeared in the April issue of PRC’s Preservation in Print magazine. Interested in getting more preservation stories like this delivered to your door nine times a year? Become a member of the PRC for a subscription!

What owners need to know about regulations, guidelines and best practices


When President Jimmy Carter had solar thermal panels installed on the White House roof in 1979, the science of human-caused climate change was in its infancy; the Arab oil embargo, however, was in the headlines, and renewable energy was understood to be key to American energy independence. (The panels were removed during the presidency of Ronald Reagan, ostensibly for roof repairs; President Barack Obama had solar electric panels installed in 2010.)

Placing solar panels atop the nation’s most famous residence was a symbolic gesture that inadvertently set a precedent. Secured to a flat roof, they were hidden from view by the White House’s tall parapet. Decades later, many preservation guidelines continue to require solar installations on historic buildings to be nearly invisible from the street.

However, growing awareness of the climate crisis and a documented increase in extreme weather events have some preservationists calling for more flexibility in the use of rooftop solar on historic buildings.

Sara Bronin, President Biden’s choice to chair the Advisory Council on Historic Preservation, has argued that the climate crisis warrants changes to the Secretary of Interior’s Standards for the Treatment of Historic Properties and the National Park Service’s guidelines derived from the standards. “New provisions could state a preference for installations that are out of public view, but if such placement would render installations ineffective, the provisions could simply require that new equipment be removable without significant damage to historic fabric,” Bronin writes in a probing essay for the University of Columbia’s 2021 publication Issues in Preservation Policy.


The preference for removable alterations has long-standing among preservationists. Before central HVAC became the norm, cities tolerated window-unit air conditioners “pockmarking building facades,” wrote retired architect and professor Roger Lewis in the Washington Post in 2020. His optimistic take is that innovations in low-profile solar collectors and even solar shingles will allow installations that are “more efficient, more compact and better camouflaged.” Until then, “integrating and harmonizing solar collectors with existing roof and facade designs, historic or otherwise, should be the principal goal.”

New Orleans is well positioned to lead the way on solar systems in historic cities by finding that harmony among property owners, solar installers and preservationists. New Orleans receives ample sunlight most of the year and has a well-established industry for installation and maintenance, thanks to a state tax credit initiated in 2007. Locally, solar installations waned when those state incentives expired in 2016, but interest revived following Hurricane Ida, which left many New Orleanians without grid power for up to 10 sweltering days.

President Jimmy Carter speaking in front of solar panels placed on the West Wing roof in 1979. Image courtesy of the Library of Congress.


Lessons from Hurricane Ida

When the lights go out in New Orleans, the home of Devin De Wulf, founder of the Krewe of Red Beans and Feed the Second Line, is one of the few exceptions. De Wulf and his wife first installed solar panels on their Bywater home, then added more panels and a pair of Tesla batteries. The system functioned reliably through Hurricanes Zeta in 2020 and Ida in 2021. “Our home is over 100 years old,” he said. “The aesthetic impact is very minimal.” The permitting process was “painless,” he added. “The installation company does it all.

“We did the batteries as hurricane preparedness,” he explained. “My neighbor has solar panels, but no battery. During Ida, his panels were just decoration.” This is true of most solar panels that are linked to the electric grid for what is called net metering. De Wulf also observed that unlike whole-home generators, which can themselves be costly to install and operate, a solar-panel-and-battery system makes no noise and emits no dangerous carbon monoxide.

In the days following Hurricane Ida, De Wulf’s home became a refuge and resource. “We provided our neighbors with phone charging, ice and everything we could,” he recalled. That experience birthed Feed the Second Line’s latest project, a joint venture with recyclers Glass Half Full called Get Lit Stay Lit. The nonprofits aim to place solar panels with batteries on local restaurants throughout the city to prevent food spoilage and provide nourishment after storms.

The growing interest in solar energy as a response to climate change is happening at a time when the cost of battery storage is coming down and solar roof tiles — often called solar shingles — have become commercially viable for private homes. “We have the opportunity to push forward technologies to make them better integrate” [with historic settings], said Jeff Cantin, owner of Solar Alternatives, a company that has installed systems in New Orleans historic districts. He welcomes increased engagement by preservationists to ensure the guidance for homeowners in historic districts continues to evolve with technology.



National guidelines

The Technical Preservation Services division of the U.S. National Park Service provides general guidance online for installing solar panels while meeting the Secretary of Interior’s Standards for the Treatment of Historic Properties. The reigning paradigm is out of sight, out of mind: “Solar panels installed on a historic property in a location that cannot be seen from the ground will generally meet the Secretary of the Interior’s Standards for Rehabilitation.” The guidance also indicates a preference for solar installations on new additions and at the rear of a property.

“It is often easier to accommodate solar hot water systems than photovoltaic systems on historic properties because fewer panels are necessary,” notes the Park Service website. “Solar hot water can often operate utilizing only a few panels, while photovoltaic systems often require multiple arrays to produce enough electricity to be worth the investment.”

Nonetheless, because of tax incentives — and perhaps because of residents’ desire for an alternative power source during electric grid outages, such as during and after storms — photovoltaic panels remain the most used, and most in-demand, in Louisiana.

The 2013 National Park Service publication, Illustrated Guidelines on Sustainability for Rehabilitating Historic Buildings, includes a detailed look at solar installations as well as the related topics of weatherization and insulation. Among the recommendations: “Considering on-site, solar technology only after implementing all appropriate treatments to improve energy efficiency of the building, which often have greater life-cycle cost benefit than on-site renewable energy.”

Purchasing energy-efficient appliances; upgrading HVAC systems, including duct sealing; and insulating unfinished spaces, especially attics, all reduce electricity demand, which, in turn, make it more feasible for a solar array to provide a greater percentage of the power required.

Homes around Uptown New Orleans with solar panels on the roofs. Photos by Charles E. Leche.


Local historic district approval

There is minimal daylight — no pun intended — between the federal guidance and local standards in New Orleans. The guidelines of the Historic District Landmarks Commission state: “The HDLC encourages the placement of all roof-mounted equipment, including mechanical equipment; vents; television dishes and antennae; solar collectors and skylights, in a manner that is as visually unobtrusive as possible from the street.” In addition, solar panels must be situated 10 feet back from the front wall, one foot below the roof ridge, and one foot above the roof eave.

HDLC approval is not required for solar installations in New Orleans’ large “partial control” local historic districts, which include Uptown and Mid-City. In other “full-control” districts — such as Algiers Point, the Faubourg Marigny, Bywater, parts of Treme and other locations — staff approval is available for unobtrusive solar installations and those on newer “non-contributing” buildings. However, a solar array that is visually prominent or proposed for a “significant” rated historic building will require commission review and approval.

Even in areas where a certificate of appropriateness from the HDLC is not required, property owners often want to strike a balance between reliability and environmental benefits of solar energy and the sensitive treatment of their historic home.

Certain historic building types are better suited to accommodate rooftop solar panels installed in accordance with the current regulations. For instance, a low-pitched roof hidden behind a parapet (quite common on Greek Revival homes) can easily block the street view of solar panels. Other building types with prominent pitched roofs are poorly suited to comply, at least on street-facing roof slopes.

Solar panels on homes in the Tremé and Mid-City neighborhoods. Photos by Liz Jurey.


The best angle for rooftop solar

Arguably, there is a disconnect between the aesthetic imperative of the HDLC guidelines, which emphasize that panels be minimally visible, and the physics of photovoltaics, which in our hemisphere yield the greatest energy production on south-facing slopes regardless of visibility. A Creole cottage with a south-facing primary facade is at a disadvantage. However, if it has a cross-gabled addition at the rear — which is fairly common — that roof section can likely accommodate productive panels.

In many ways, the densely packed shotgun doubles that front many New Orleans streets are well suited for solar installations that are minimally visible, particularly if the primary facade faces east or west (producing a substantial south facing roof area). Existing tree cover can affect the productivity of solar panels; similarly, properties on corner lots often have more roof area visible from the road.

Some early 20th-century building styles, notably Spanish and Mediterranean revival, are characterized by tile roofs. Other properties may retain slate roofs, sometimes with decorative patterns. Given the character-defining nature of these roofs, visible solar installations are unlikely to gain approval in a full-control local historic district. Furthermore, while solar panels can be installed on a tile roof, it is often a costlier process that requires care be taken not to damage tiles.


Asbestos roofing was common in the early 20th century and has proven durable to this day. But securing a solar array to an asbestos roof is complicated due to the toxic nature of the roofing material.

Meg Frazier’s mid-century home in Metairie was recently renovated with extra insulation and efficient appliances when her multi-generational family moved in. However, with four adults in the home, they still needed ample power. Frazier invested in 40 solar panels and two Tesla Powerwall batteries. “I have always wanted solar,” she said. “This was the perfect house because it’s east facing with a long [south-facing] rectangular roof area.”

When Ida made landfall, Frazier was nervous that flying debris or high winds might damage her recent investment, but she was relieved when the storm passed with no damage. “I was thrilled with how the system worked,” she said. “We were still pulling solar power in the middle of the storm.

The solar system allowed Frazier’s family to run their appliances, fans and even air conditioner for limited amounts of time. It has also changed the way she thinks about electricity. Frazier makes a point to plan discretionary uses, like laundry, for evenings when her batteries are fully charged. “My appreciation of and attention to energy is really different now.”

Nathan Lott is PRC’s Policy Research Director and Advocacy Coordinator.