The history of the window and its impact on home design.

Dr Howard Decker, National Building Museum, Washington D.C. explains that “the shape, character and construction of the window have an enormous effect not only on how our buildings work and how it is to live in them, but also how they look.”

We decided to explore the history of the window to understand its evolution and the relationship between windows and the way we live. We wanted to consider the purpose, function and design of windows as related to home design and consider the design and performance of modern windows to understand what makes great fenestration.

In the beginning, windows were nothing more than holes placed in a wall or roof to let light in, or arrows out (inevitably allowing heat to escape too). The role of the window evolved over the centuries in line with human needs. Beginning as small arrow loops from which we were able to defend ourselves, windows developed overtime into grand apertures exemplifying status and wealth.

In a “Brief history of windows,” the British Plastics Federation explain that “the use of glass for architectural purposes began at the end of the first century AD when the Romans discovered that adding manganese oxide to the mixture made clear glass, albeit with poor optics. This glass was only used in the most important buildings.”

Glass remained a precious commodity for centuries with many dwellings simply covering their “windows” with wood, furs or other materials as opposed to using glass panes. Even after glass became more widely used, it was generally of a poor optical grade. From the Middle Ages, most people only encountered it by way of the awe inspiring and status conferring windows found within churches and cathedrals. Here stained glass of vivid colours was used to dramatic effect to teach the illiterate the basic Christian message, and to inspire them to live holy, prayerful lives.

Stained glass windows in all their grandeur were often used to depict and affirm the social order and hierarchical society. A window originating from the 1450’s in Gloucester Cathedral shows shields of nobility and layers of social hierarchy from the Saints right through to the illiterate peasantry — just in case anyone was in any doubt about the natural order of things! Tatler magazine lists the window as a status symbol in their story, “All for show: A short history of the status symbol,” stating that after the English window tax of 1696 the, “truly grand folk just put in more and more windows.” They go on to cite Blenheim Palace as a prime example.

Unfortunately for most, the 1696 window tax meant that “landlords boarded up windows or constructed new buildings with insufficient windows and as a result, tenants suffered from inadequate ventilation and natural light, leading to epidemics of typhus, smallpox, and cholera,” explained Dr Rachel Hurdley. A sanitary report published in 1845 stated that the local health committee have “…witnessed the very evil effect of the window tax… in some cases (it has) been the primary cause of much sickness and mortality.”

According to Architect Magazine, “windows are one of the most expressive and vital features of a building, serving as part of the thermal envelope while affording light transmission, sound control, and natural ventilation.” This was not always the case however and it is interesting to note that throughout history the real purpose of a window has rarely been architectural design or occupant health. We have seen that as a precious commodity, glazing remained the preserve of the wealthy, and defence and security dominated how “windows” looked and were constructed for many centuries.

History shows a stark contrast between different types of buildings and the type, size and number of windows they displayed. On the one hand palaces such as Blenheim (with more than 1000 windows), used their fenestration to heighten the sense of drama, grandeur, and opulence of their architecture. At Blenheim the higher your status the more light you benefitted from, as windows were strictly arranged according to social status. Servants’ quarters had the smallest windows and therefore the least light. On the other hand, (as shown above) landlords had no qualms boarding up windows or not installing them in the first instance, when a building was destined to house the poor. Ultimately the requirement for basic shelter and protection from the elements took higher priority than did the quality of daylight. Protection from the elements therefore heavily influenced the types of windows utilised and factors such as aesthetics and health were far less important in most instances. The definition of “window” therefore remained loose for centuries and included wooden boards and other covers e.g. fabrics and furs that were used to shut out the weather, right into the 20th Century in the west.

Another factor that heavily influenced the type of windows we used, their quantity and design was our ability to heat our homes. We explored the relationship between how we heated and glazed our homes in our recent story “The weather indoors.” We described how up until the advent of better designed and manufactured windows and heating in the early 20th Century, the pleasure of a room was ultimately founded from the weather it was keeping out. This was illustrated by novelist Thomas DeQuincy who called for, “a Canadian or a Russian winter, the better to heighten the contrast between indoors and the world beyond,” in recognition of the protection from the elements afforded by windows and the resulting safety he felt once sat beside the fire within.

“The Weather Indoors” describes how in the 20th Century, as engineers and architects solved the problems of the weather getting in, the way we designed our spaces was able to change. The advent of mass production, climate-controlled interiors, and advances in weather technology all significantly influenced architectural design. In 1927 French Architect, Le Corbusier shared his all-encompassing vision for modern homes with “respiration exacte” and “double windows.” According to Professorial Fellow in English at the University of Birmingham, Alexandra Harris, Le Corbusier believed that in the age of technology, people should be unaffected by the elements in their homes. He designed a house “whose breathing / airy circulation would be precisely controlled with switches” to provide a constant 18-degree temperature year-round, because he believed that humans functioned better at some temperatures than others.

Crucially for our exploration of the window in home design, Le Corbusier’s vision was achieved with the invention of the world’s first double glazing or “double windows.” His vision was that inside our homes we would see the weather, but we would not feel it. Previously rooms, and their windows, had mostly been small and “womb-like” (W.H. Auden), and fires large. But as buildings began to perform better at keeping the weather out and the heat in, the result was the modern home. “Double windows” enabled windows to get bigger. Warmer interior conditions meant that dividing walls could come down, and radiators made it possible to live in open plan. The air flowed through, and the light poured into the interiors of the 20th century. Alexandra Harris described the opening up of space with the additions of double glazing and central heating as “an entirely new era.”

The post-war house building boom saw living conditions improve exponentially. More of us became able to access quality housing including housing with well-designed fenestration. During the 20th Century the modernist home with large windows and open plan living became so influential that it is still regarded as being highly desirable today. We actively reference the homes of Frank Lloyd Wright and some of the Case Study Houses in our work at Kiss House. However, as beautiful as homes with predominantly glazed elevations can be, they do overheat to the point where they can be unbearably hot on sunny days, and uncomfortably cool on cold days. Even though modern windows are subject to highly advanced engineering and are treated as integral to building quality (in the best quality buildings), this problem has not gone away. A recent exhibition entitled “Picture This” at the National Building Museum in Washington, D.C, described the ultimate modern window this way, “Today they (windows) function as integral components of complex building envelopes, selectively filtering aspects of the larger environment. As manufacturers have developed new technologies to improve visibility, security, and comfort, windows have become elements of sophisticated systems that control light, ventilation, moisture, dust, sound, and even infrared and ultraviolet light.”

The window has come a long way and the best modern windows are highly sophisticated and brilliantly designed, they look great and perform exceptionally. But for all of our engineering and scientific advances, we are far from being able to say that everyone now benefits from well designed, high performing windows. As Professor Ffionn Stevenson, Professor of Sustainable Design at the University of Sheffield, School of Architecture, cited in the article, “Windows deliver a lot more than just light and air,” states, “the resilience of a well-designed window is infinite… but we have so many unusable windows installed in the UK. Unnecessary restrictors, poor handle design, overly complex opening systems, poor seals and frames and finite double-glazing performance. We can do better than this!” Of course, it must not be overlooked that any window is only as good as its installation!

Getting fenestration right is a multi-faceted design, manufacturing, and installation task. Specification is critical — the gold standard in glazing is triple glazing, however there is a wide range in terms of quality that is dependent upon glass coatings, optimal spacing of panes, use of gas within the sealed units, detailing and more. The windows themselves need to be correctly specified as part of a whole building approach to thermal performance, meaning the size, position and quantity of glazing is carefully balanced. The thermal performance of a building is also affected by factors such as position of the building itself, local shading, e.g. from buildings or trees and local climate. The design and detailing of the building and the materials used are critical — after all windows function as integral components of complex building envelopes. A great way to get this right is to model the building using the Passivhaus Planning Package (PHPP), because this balances all relevant factors to achieve an understanding of how the building will perform at all times of the day (and night) and at all times of year. The aim of the PHPP modelling is to ensure that the building remains at a constant ambient temperature year-round and is unaffected by spikes in the weather. Correct installation to ensure manufacturing tolerances are appropriately filled and air-tight and weather tight seals are correctly made is another critical factor.

Beyond this fenestration should be designed to make us feel good. It should ensure good daylighting within the space, because spaces that benefit from good natural light are good for those who inhabit them. Helen Sanders, writing in “The Construction Specifier” magazine says that a lack of sunlight “can cause circadian rhythm disruptions that, in addition to causing poor sleep, can alter moods and cause depression and long-term health problems.” You can read more about circadian rhythms and Human centric lighting in our story about it here. The other fundamental factor to ensuring our enjoyment is aesthetics — good aesthetics both in terms of external and internal appearance. Though we have come a long way in terms of the quality of windows available and our access to them, there are still issues found at both ends of the home size spectrum. The UK is often criticised for having small homes with undersized windows with numerous reports including reviews of new build homes by the RIBA and the Bartlett Review finding that more than half of developments surveyed are below minimum space requirements and suffer from poor daylighting. Whilst it is a fact that some homes are small and can’t easily be made bigger, it is none-the-less true that good glazing can improve the sense of light and space within.

At the opposite end of the spectrum in recent years an architectural style coined “the McMansion” has emerged. McMansion is a pejorative term that describes a large, often ostentatious house which is said to lack architectural uniqueness and coherence. Speaking on the 99% Invisible podcast, in an episode called “McMansion Hell, the devil’s in the detail,” Kate Wagner critiques these homes as being built “without consideration for the grammar of design.” She cites the inclusion of multiple styles of windows within a single façade as a confusing and unappealing design feature and says that “a proliferation of window shapes makes it increasingly hard to form a coherent architectural design.” Whilst Wagner’s McMansion Hell blog is somewhat tongue in cheek, she makes some interesting and valid points about fenestration. Ultimately there is a grammar and a logic to good home design which must extend to fenestration — as Wagner says multiple styles together and a proliferation of window shapes makes for an unappealing and confusing appearance. The opposite of this being a single style and a coherence to shape. Interestingly the “National design guide” provides three “good practice examples” on page 45, and two out of  the three refer to fenestration. “1: House frontages are carefully designed with generous windows from habitable rooms…” as exemplified by Caudale in Camden, London. ”2: Internal habitable rooms have high levels of natural daylight and connect well to gardens and terraces,” as exemplified by Accordia in Cambridge.

At Kiss House we have refined our fenestration over time. When we launched our first designs, we included a significant amount of full height glazing to the south (principal elevation). This expansive glazing tapped into the modern home aesthetic and had wide appeal however, when we began a process of review, we decided to reduce it. We would not run the risk of a Kiss House home over-heating, nor would we want to be overly reliant on shading strategies to achieve interior comfort. The result was that we made a reduction in glazing of 40% overall.

As we have progressed the design of our proprietary house building system, we have developed a set of simple principles regarding fenestration. These principles remain consistent across all Kiss House homes. The key is simplicity — we are called Kiss House for a reason after all! The objective of our principles is to ensure the optimal balance between performance and aesthetics. Exceptional Passivhaus performance is essential meaning the quality of the glazing units we use, and how they are installed is critical. We model all Kiss House homes to ensure the building will achieve Passivhaus certification and provide optimal occupant comfort based upon the specific location. We also work hard to ensure that the fenestration looks great both in terms of the external elevations and detailing and internal detailing.

Our principles are:

• Meaningful repetitive openings — standard opening sizes are used across all Kiss House homes, and are placed to bring natural light, access and fresh air to key internal spaces. Repetition provides coherence and balance
• Natural light — roof lights and large windows are used throughout to bring natural daylight to the internal spaces across all Kiss House homes
• Double storey glazing — used across the front elevation of each Kiss House home, to bring direct views onto the feature staircase and through the building
• External detailing — simple detailing including a shroud feature to bring some shading and relief to the elevation, used to define openings across Kiss House homes
• High performance triple glazed windows, modelled in PHPP and correctly installed — the use of DfMA enables greater precision and reduced tolerances around windows (than can usually be achieved) ensuring a more robust interface

The development of these principles has resulted from a process of design refinement and a willingness to experiment. It is not easy to balance sometimes competing priorities, and to design out fuss and complication, however this is often the challenge we have to face. We have been pleased with the results, as shown in the example images.  We have managed to maintain our simple modern aesthetic, whilst simplifying further and achieving a more minimal elevation, this adds a heightened sense of understated domesticity which in turn provides a greater sense of privacy.

Clearly windows have come a long way from their lowly origins to the high-performance glazing that is available now. Likewise attitudes to the window and fenestration have changed dramatically. Exploring the evolution of the window has given us a deeper insight into the significance of the window and the importance of getting fenestration right, and we have a greater appreciation for the impact that well designed fenestration has on a building’s inhabitants. Getting fenestration design right is multi-faceted. The best results are when it is regarded as an integral part of building design and performance. We wonder what the next 1,000 years of the window will bring and are very excited by the research and development being undertaken by companies like NSG Pilkington, but that’s a whole other story…

Thanks for reading,

Carli

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Resources

Brief history of windows: British Plastics Federation

Windows deliver a lot more than just light and air

The hidden history of a window

All for show: A short history of the status symbol

Pulling back the curtain: A brief history of windows

The weather indoors

“Picture This,” the National Building Museum, Washington, D.C

Should daylight admissions be mandated through building codes?

McMansion Hell, the devil is in the details

National Design Guide