Sunrooms in various forms have been popular in many cultures for many, many years – perhaps longer than you might think.
Authors Ken Butti and John Perin, in their A Golden Thread — 2500 Years of Solar Architecture and Technology, chronicle the roots and evolution of today’s modern sunroom.
China, 6000 BC
From an architectural point of view, sunrooms as a source of supplementary heating have their roots thousands of years ago. Around 6000 BC, the Chinese built the opening to their homes facing south so the sun would heat the interior. Two thousand years later, Chinese urban planners constructed the streets in towns to run east to west, giving homes a southern view and a source of winter supplementary heating. To this day the Chinese still prefer a home facing south.
Greece, 500 BC – 100 BC
In ancient Greece, both Socrates and Aristotle advocated designing houses that could take advantage of the sun to provide winter heat. Socrates, himself, lived in a solar-heated house. Archaeologists have discovered that the Greeks took the philosophers’ advice, and implemented plans for all city and rural homes to face the winter sun.
Italy, 100 BC – 500 AD
One of Rome’s greatest architects, Vitruvius, wrote about using the sun to heat buildings and bathhouses after seeing solar houses in Greece. His advice was apparently followed as bathhouses from 100–500 AD were built with large, south-facing windows to let in the sun’s heat. These windows were covered with a transparent stone, such as mica (a natural substance like glass that breaks easily into thin layers and is not damaged by heat) or clear glass (a Roman invention of the 1st century AD). The Romans discovered that transparent glass acted as a solar heat trap, keeping temperatures inside a room quite warm.
Most affluent Romans covered their south-facing winter rooms with mica or glass. A room with a glazed window was called a “heliocaminus”, which translates to “solar furnace”. These glass Roman windows created higher temperatures in the home than the earlier Greek solar homes achieved with their uncovered windows. In the second century AD, glass and other transparent materials to cover windows became more common. By the sixth century AD sunrooms in houses and public buildings were so prevalent that the Justinian code created sun-rights to ensure individual access to the sun.
Italy, 14 AD – 37 AD
The ancient Romans also built greenhouses to help plants mature, to grow fruits and vegetables in the winter, and to raise exotic plants at home imported from warmer climates. An early form of Roman greenhouse was first developed when an ailing Emperor Tiberius was prescribed daily Armenian cucumbers by his physicians. A house dedicated to growing plants out of season was built, with a translucent roof made from thin sheets of mica to allow the sunlight indoors. Oiled translucent cloth sheets, called specula, were used as well as mica for the roof (the house was called a specularium). Fires were maintained constantly outside the stone walls to heat the air inside.
The Emperor’s resourceful gardeners also grew beds of the Armenian cucumbers on wooden carts and rolled them into the sunlight during the day. At night they were moved inside the specularium to keep them warm. During the colder days of winter the cucumbers were also stored in a hole in the ground, and covered with translucent stones (mica or selenite crystals – selenite is a colorless, glassy variety of gypsum) to hold in the solar heat. Later forms of greenhouses ranged from glass-covered receptacles to glazed, south facing walls that captured the sun’s warmth. However, with the fall of the empire, the use of glass for buildings and greenhouses also collapsed.*
Italy, 1201 – 1300 AD
The first true greenhouses were built in Italy around the thirteenth century, and were called “botanical gardens”. They were developed to store tropical plants from around the world for medical research, and were designed to capture enough sunlight and warmth for the plants to flourish. The two earliest botanical gardens were located at the Vatican and Salerno.
Korea, 1450 AD
During the 1450’s, greenhouse development occurred around the world. For example, in Korea, temperature controlled greenhouses were built using underfloor heating (ondol) to maintain heat and humidity during the winter. Cob walls insulated the heat, and semi-translucent, oiled windows, constructed from hand made paper, provided light and protection for the plants from the cold.
Italy, 1545 AD
Around 1545 the first orangery (a greenhouse or sheltered place for orange trees and other delicate plants in cold climates) was constructed in Padua, Italy to house orange trees and other citrus fruits during the winter. It was a practical building that could be totally covered with planks and sacking, and was heated inside with open fires. At the end of the Eighty Years’ War in 1648, orangeries became very fashionable in Germany, France and the Netherlands, as their merchants began importing great numbers of banana plants, pomegranates, and orange trees.
The technology of glassmaking could now provide large numbers of clear windows for these orangeries, which had many tall windows that faced south, as well as brick walls and sloping tiled roofs. They were heated with stoves, and later in the nineteenth century, sophisticated floor heating systems were used.
Orangeries soon became status symbols among the wealthy, who built them in their gardens and grounds. In the summer, the tub plants, citrus trees, and Cape plants (from the southern tip of South Africa) were brought outside for decoration. Fountains, grottos, and entertainment areas eventually became part of the orangery architecture.
In 1664 John Evelyn used the term “conservatory” to distinguish this glass-roofed structure from an orangery. A Conservatory was more suitable for plants that grew and flowered in the winter because of the perpendicular sunlight from the roof. Beds of earth were formed on the floor for the planting of trees and shrubs, instead of keeping them in tubs and boxes, as was the custom in orangeries.
In the nineteenth century the conservatory also became distinguished from a greenhouse. A conservatory developed into a structure where a few large plants were grown for their exotic, scenic effect. It was attached to a mansion, usually off the drawing room, where the family could go to enjoy the sunshine among the plants.
In contrast, the greenhouse was a place to grow many different kinds of smaller, exotic plants in pots, which were elevated on platforms to bring them closer to the light. It was meant for smaller suburban houses, and also could be attached to the residence.
Health Benefits of Greenhouses
As scientists explored how greenhouses benefitted plant life, they also realized the same concept could benefit human health. In the early twentieth century, hospitals began using solariums (glass rooms) to help people recover from illnesses like pneumonia, pleurisy and tuberculosis.
At the same time, homeowners, who enjoyed their covered back patios or front porches, were looking for ways to extend their use. To accomplish this, some added storm windows to their screened-in porches for the colder weather.
North America, 1960
In the 1960’s, patio enclosures were advertised to single families living in suburban homes built after World War II. These enclosures were so popular that a market developed for better designs, quality, and engineering.
To this day sunrooms are more popular than ever, with many types, designs, and sizes to choose from. Their many functions, such as entertainment room, sanctuary, home office, or guest bedroom, can be utilized year-round. With today’s modern construction materials, the sunroom also delivers what our ancestors valued highly in their homes — solar heating.
For the finest in sunroom design and construction, call Sunshine Sunrooms at (972) 243-5390.