There is certainly some disagreement between so-called historic preservation purists and those who roll a little looser. In modern preservation theory there is oftentimes more emphasis given to interpretation than a recreation of every physical detail. I would note there are many sites which employ LED lights, which often save money and electricity, but the lights are usually colored or filtered to more closely resemble the historic appearance. For example, many of the fake candle flames like you might see in a lantern or chandelier are LEDs now. For buildings open to the public, there is also consideration given to safety and access for those with disabilities. The modern visitor is generally not used to very low light levels. Each site has to find a balance.

Lighting is not usually regarded or taught as a primary design feature in architectural history, but often framed as a byproduct of the design and available technology. This is perhaps unbalanced. Since electric lighting is relatively new in the space of human history, the relevant lighting is usually natural. Gothic cathedrals, which were masonry-bearing buildings, had a limited amount of wall space that could be given up to windows. Innovations like the ribbed arch and the Gothic arch itself in the High Middle Ages actually allowed for thinner walls and increased window size. Still, some of this light was given up to the effects of stained glass due to the desire for a "heavenly" quality to the light in these religious buildings.

Looking at late nineteenth and early twentieth century office buildings (e.g. Chicago style, commercial style in the United States), the typical floorplan was windowed offices lining dark corridors. Larger buildings would have lightwells, or courtyards, or be U-shaped to allow more avenue for light to enter. The institution of iron/steel structures and increased affordability of plate glass also allowed for larger windows. The tripartite Chicago style window is an example of a design feature that came out of this period. Another good example is Miesian modernism, the steel and glass buildings (skyscrapers) of the mid-twentieth century. This style clearly let in a lot of natural light. However, the windows were typically fixed and such large, uninsulated glass areas and limited ventilation led to uncomfortably hot spaces.

The point is consideration is given motivation behind the lighting which would have been present in a historic building and the role it played in the architect's vision. The stained glass in most Gothic (and some revival) buildings would be considered a character defining feature because of its multi-layered significance. A Chicago-style skyscraper that is now getting less natural light due to the density that has grown up around it might be able to use artificial lighting in a sympathetic manner, with less loss of character. It is a manner of opinion to some degree, as to what justifies retaining or not retaining any given historic feature, and, practically other considerations are given.

​

Sources:

Frankl, Paul, and Paul Crossley. 2000. Gothic architecture. New Haven, CT: Yale University Press.

Grimmer, Anne E. "Secretary of the Interior's Standards for the Treatment of Historic Properties." Washington, D.C.: United State Department of the Interior National Park Service. 2017.

Leslie, Thomas. 2004. “Glass and Light: The Influence of Interior Illumination on the Chicago School.” Journal of Architectural Education 58 (1): 13.

Schulze, Franz, and Edward Windhorst. 2012. Mies van der Rohe: a critical biography. Chicago: The University of Chicago Press.