Another Erica novella:
When we talk about "non-glass windows," especially "before-glass windows," we may be mis-reading history.
I have heard the "eye" reference in the name, which someone mentioned earlier, is "wind-eye," a place to let the breeze blow in. This source says it originally referred to a smoke-hole in the roof, which (in the gable) might also be called an Owl-Eye.
http://en.villumwindowcollection.com/history-of-the-window/
Northern Europe: Wooden Shutters, to Translucent Leather, to Glass
The Villum website describes a history in Denmark, where
local window coverings evolved from wind-eye smoke-holes with a wooden cover or shutter, to a stretched-hide cover, to a translucent cover of parchment, bladder, or amniotic sac leather. Then glass comes in as trade goods and artisan crafts (glass "gems" and enameled metalwork being common in antiquity), appearing in windows first as stained-glass religious
art for stave-churches.
(Side note: religious
art probably also included smaller duplicates, using local materials like horn, agate, and exotics like ivory, for religious take-home art. Think kitchen-window suncatchers; I've seen religious metalwork with enamel, ivory, or glazed panels in museums but don't know the era).
I have heard that rich nobles in feudal England would take their favorite bed, some pretty window frames, and other furnishings when they travelled between castles. A window-covering would be a portable art object, like a stained-glass version of a painting, not a permanent part of the building.
Back to the Villum history: Glass windows finally appear commonly in homes (as small panes in mullioned or sash windows) starting in the late 1500s to 1600s with the colonial/high-seas trade era.
(Wasn't this also right around the Little Ice Age, 1400s onward? The 1600s and 1700s include a lot of furniture styles and drapes designed to exclude drafts, like wing-back chairs, and the Rumford fireplace for light as well as heat.)
Viking-era homes had "small windows, covered at night with shutters."
http://www.localhistories.org/vikinglife.html
If your goal is to block storms and beasts, and you have perfect light when the shutters are open, why put a lot of effort into something halfway between open and shut?
Contemporary "traditional" shutter designs show patterns like louvers, fiddlework cutouts, etc, which would provide a little bit of air and light during storms, and could presumably be stuffed with rags on a very cold night. Though more likely, you'd retreat to a warm bed and use the rags for quilts.
If you've explored old barns in daylight, you will recall how quickly the eyes adjust to seeing pretty well in the gloom, if there are a few cracks to let in the light. A crack is a LOT more than nothing.
Roman: Translucent Stone, Reflection, and Glass
Did Roman, Persian, or other ancient empires build covered windows? Their climates were warmer, and I don't see much evidence of window coverings in most imperial homes. Many had clever ventilation plans that relied on windows as part of convection-driven cooling air flow. Many had stone privacy screens, with fretwork, and I've heard suggestions of alabaster or marble panels for translucent effects.
Wikipedia mentions "
Diocletian windows" being used to hold the heat in for public bathhouses.
Romans imported fancy stone from the 2nd century BC, including colored marbles, and used white stone extensively in walls and window frames (white reflecting light best).
http://www.ancient.eu/Roman_Architecture/.
(I seem to recall Inca ruins also having a lot of light-colored stone work, though I don't think they imported as extensively.)
Here is a Roman home architecture page; note the elegant interiors, with very little evidence of natural light.
http://www.crystalinks.com/romebuildings.html
Reflective materials like gilding, silver, tin sconces, mirrors or metal, glass, or glossy tile have been very popular for reflecting light. In addition to horn, ivory would have been used historically for translucent screens and light-colored art.
In modern times, with our tools for cutting stone very precisely into slabs, I've seen stained-glass style art using natural stone like agate,
rose quartz, thunder-eggs (agate), etc.
The only Classical buildings that I notice being built for glazed windows are the Neo-Classical works of the 18th century (1700s) and onwards.
"Windowless" windows - what good is that?
How did our pre-industrial ancestors not see a need for glazed windows, or any substitute we would recognize? Most people today in developing areas seem to really love getting artificial light, it expands the social day. Presumably indoor light would be valuable? What did they do for light, if indoors was so dark all day?
I think they went outside.
People didn't live indoors during the daytime as much as we do now; most people spent a lot of time outdoors, more than half the population was involved in outdoor work remember. City-dwellers might have indoor jobs, but even then, you might have big outdoor work-yards for common manufacturing, and "cottage industries" could be done in a doorway or porch not necessarily indoors. Indoors is occupied 80% of the night, but not necessarily more than 20% of the day, at a random guess.
If you want to work indoors, you can create big openings to let the light in, more like we would think of a door than a window, and shut them at night. Doors also let in your customers, and them 'darkening your door' would be a subtle alarm for a merchant, like flickering the
lights at theater intermission.
In temperate and sub-arctic climes, where the nights get long, you have a lot more indoor entertainment with fire, and larger numbers of people gathering around those fires in smaller spaces than today. Windows would be useless against the long nights. And you'd have a LOT more outdoor work during the long summer days, to get ready for another long winter. I suppose ice, as in igloos, would be the ultimate natural window material. Certainly snow serves as insulation, in areas that can build stout
enough to handle it. Maybe some Scandinavian children somewhere have made "ice-windows" by reinforcing the already-dense icycle layers that stream from the edge of a poorly-insulated eave in winter.
It was rare to heat the whole of large buildings the way we do today. A heated room would be a public or private luxury: Turkish baths and Roman caldariums, Scandinavian saunas, North American sweat lodges, etc.
At home, well-off or cold-prone people used personal warmers (brasiers, pots of embers, hot stones or bricks, hot-water bottles, small dogs with a foot fetish).
Rich and poor created smaller spaces that warmed easily with body heat, like cupboard-beds and
canopy beds, with quilted enclosures or heavy velvet drapes. Servants' quarters were often near the kitchen (or in the kitchen) where they could sleep near a warm hearth. People who were not rich enough to have servants had small homes, often one room, and shared beds among siblings as well as married couples. I've heard of Granny inviting a favorite grandaughter into bed as "her little back-warmer" as late as the 1930s. We did not leave this pattern so long ago.
Working rural families did not live indoors, historically, or expect perfect thermal controls even in urban offices. Nobody would expect the indoors to stay at 70 F (20 C) all year round - the fact that it was substantially more comfortable than outdoors, and safe from beasts and storms, would be considered sound
shelter. If you have a good thick quilt, or are sleeping two or three to a bed, you can even survive indoor frost (though that might be cause for complaint, even then).
Glass windows appear in huge numbers with the industrial revolution, in both domestic and commercial buildings. I think one factor (besides elegance and comfort) was just how dangerous open-flame lights were. Aside from the fumes of combustion, or gas leaks, a factory or processing plant would usually be full of fine dust from textiles, grain, coal, metal work, etc. Dust is far more combustible than the solid products, often explosive, and a factory could easily have a catastrophic fire. You see a LOT of windows to allow cheap, safe, natural daylight into these factory buildings from the later 1700s and 1800s.
And after those industrially-produced windows become common, then you hear about the pioneers and settlers using cheaper, less-fragile substitutes, like skin, oilcloth, oiled paper, or anything that would admit a little light while keeping the wind out. Covering your windows became a convenience, a mark of civilization, and those coverings were now expected to let in light.
Fabric curtains were another big thing that "ma" would insist on, in distinguishing her house as a proper home.
These could also cut down on mosquitos and flies. While the theory of mosquito-born disease wasn't common yet (the Wilders books spoke of "bad air" or "ague" in the wet bottomlands), people might still observe a health correlation with "civilized" behavior like hanging lace curtains or having something solid across your windows. If so, it would have reinforced the preference to appear 'civilized' even without knowing exactly how it worked. Mosquito netting is a life-saving tropical convenience, in part because not all homes have screened windows - letting the air through during the hot days is also a health consideration. A slightly smoky home with fabric curtains might deter evening blood-seekers well enough to reinforce the "hygenic" bias toward civilized comforts.
Biological Gels as Glazing
I stumbled across one final, interesting option for the original question about materials.
I was looking for "isinglass" (which is a word used for two different things: fish swim-bladder gelatin, and sheet mica). turns out they did not apparently make biological translucent curtains for carriages (not that I've seen, anyway). that was sheet mica.
But translucent gelatines have been used to repair parchment, sometimes with the addition of natural sugars/syrups for consistency; and for preserving eggs (like water-glass, or sodium silicate). Presumably, you could paint gelatine or waterglass over very fine, stretched white fabric, such as muslin, or use it to make "oil-cloth" analogs using thin parchment, or to reinforce something stitched out of the original fish-skin or swim-bladder or animal-hide translucent materials. Seaweed, aloe, or other clear botanical gels could be used in a similar way. Rabbit-skin glue is the traditional 'sizing' for canvas, to prepare it for painting; skin and bone glues, if carefully made and refined, are a smellier version of something that functionally resembles Elmer's white glue (now made with polyvinyl alchol). Bone and hide glues often must be heated, like horn, and can be more waterproof than the other gels I mentioned once cooled.
The other biological-gel materials would likely not tolerate damp conditions well (being similar to agar used for petrie-dish experiments), but are used in dry conditions for paints, plasters, etc. For indoor art work (under wide eaves in dry walls, for example) they might raise some fun possibilities. Other paint and plaster media that I know of include a translucent milk-protein gel (
milk plus an alkali like lime; borax is used for "borax glass" and could remain clearer than lime after painting). Egg protein, both yolk and white (the white dries clearer, the yolk is a better suspension emulsifier for pigments, and has more oil).
Sugar-glass is used in Hollywood for safe stunt work, and in gingerbread houses. Think "stained-glass cookies" (there are recipes
online). Again, in a context where it would stays dry, it is an interesting medium to play with.
You could combine exterior dry "rooms" (collonades, porches, etc) with enormous light-admitting openings, paint or build them of white materials to gather lots of light, and use an interior light membrane made with materials that are not themselves weatherproof, to let in beautiful light while blocking wind. I would consider these edible-glazing options for something like a cupboard-bed, or between interior rooms, if your climate would allow it to stay dry and not get ridiculously sticky.
Maybe translucent edible-art pieces could be oiled, to limit the moist-and-sticky factor.
In my house, any stored examples would probably get gnawed by rodents within months. They would need to be mounted in dry, exposed locations where most vermin are not comfortable settling down for a snack.
Could be a fun thing to try for kitchen-window art.
Why not glass?
If you're just looking to reduce embodied
energy by not buying new glass, there's always the recycled bottle-glass approach, too.
Our modern world has a lot more available, translucent synthetics, and many of these are shamefully under-appreciated. You could make beautiful mullioned windows or shutters using panels cut from 2-liter bottles, for example. Foil packaging can become
solar reflectors, perhaps on the interior or shutters, to allow light-catching at all hours of the day, and to reflect artificial light such as a candle on the windowsill when closed at night.
Window art is probably the highest purpose for some of these materials, which are often down-cycled to "useful" materials like gravel or playground paving.
Now I want bottle-green mullion shutters to go over conventional windows, as weird home-made "storm windows." I wonder how it would work. I definitely do not drink enough 7-Up to supply my own materials for this experiment.
Day-lighting Without Glass or Synthetics:
If you want to heat a large, modern space, for thermally-controlled comfort and convenience, with beautiful natural daylight, then glass is a pretty good option. It's non-toxic, and while it does have embodied energy of manufacture, the embodied energy of any functional substitute is going to be substantial as well. Glass also has the weird 'advantage' of turning into a sharp defensive barrier if broken - so glass windows are psychologically more secure than an uncovered opening of the same size.
Recycled windows, high-performance glazing chosen for thermal functions or passive
solar, or bottle-glass art are probably your most functional, responsible substitutes for a space that suits the luxurious, modern lifestyle.
If you want a space that doesn't require glass, but has lots of natural light, the easiest thing is to abandon heating it with warm air. Then you can use windows as they were originally used for thousands of airs: as ventilation openings.
When it's too cold for open windows, close the bigger ones with shutters, use radiant, conductive, or mass-storage heat to limit heat loss through remaining openings.
Or create large beautiful unheated spaces and small, insulated spaces for heating as needed.
If you want a space that has ample daylight, does not rely on energy-intensive artificial light, does not use glass, and has stable indoor temperatures, I think living in a tropical climate might be your best bet.
Or you can re-define "ample" to mean very small windows with a lot of bright white or reflective surfaces, treating each membrane-covered window as a sort of light-well or SolaTube.
If you want to make beautiful, all-natural, stained-glass analogues as works of art to seal small windows in hand-built sanctuaries, aka nature-based SolaTubes, all of the materials listed by everyone will give you options.
Now we can walk through the world, watching how the sun catches or reflects in every object, and keep adding to this list.
Has anyone tried oiled
wood, like birch paper or very thin pine panels? Planer shavings can be translucent.
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