Casting fossil fuels aside, she invented the first domestic solar heating system that could store heat from the sun to use when it was not shining. She built it straight into one of the most celebrated homes of modern architecture: the Dover Sun House. It marked a watershed moment in the career of a scientist who soon came to be known as the Sun Queen.
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A trio of women brought this building into being, choosing the Massachusetts countryside, where heavy snowfalls and overcast days are par for the course throughout the winter months. Architect Eleanor Raymond took charge of the design, sculptor and patron Amelia Peabody funded the build, and the scientist Telkes devised the ingenious heating system in partnership with the Massachusetts Institute of Technology (MIT).
The house had an astonishing profile for residential architecture in 1948. Form was subservient to function, which was to capture every ray of sunlight. Yet the result was striking: clean lines, expansive glazed surfaces, uncluttered visual symmetry, and a bold wedge shape; a radical departure from the rustic setting in which it stood. The pitched roof covered around 150 square metres, laid out across two bedrooms, a bathroom, a kitchen, and a living room.
The system relied on expansive south-facing glazing across the facade to harvest thermal energy from the sun. The collector consisted of two layers of glass with an insulating air pocket sandwiched between them. The inner pane rested against a blackened metal plate. Incoming solar radiation passed through the outer glass, warming the black surface, which then transferred that heat to the air trapped in the cavity. A network of fans channelled this warm air down into storage compartments tucked away beneath the living quarters.
These compartments were filled with drums containing Glauber's salts (sodium sulfate decahydrate), which become liquid at 32 °C. When it was cold and the room temperature dropped, the salts crystallised again and released heat. This heat was distributed throughout the room by a fan.
The system used the glazed frontage on the south-facing facade to capture heat from the sun.
The building was conceived as a real family home, not a laboratory experiment. Dr Anthony Nemethy, Telkes’s cousin, soon moved in with his wife Esther and their three-year-old son Andrew, having fled Hungary during the Soviet occupation. Life in the house balanced ordinary domestic routines with the thrill of being part of a scientific breakthrough that deserved to be shared. Over the first three years they lived there, the family opened their doors to the public a couple of days a week, welcoming some 3,000 visitors every year.
A few years after completion, the heating system began to falter: the salt compound proved corrosive and began leaking from the drums. Despite these practical limitations, the experiment became a landmark in the solar research of its era.
In 1954, a conventional furnace was installed, and the Nemethys remained in the house for the rest of their lives. The building was eventually demolished in 2012. Today, a new home stands on the plot, complete, of course, with its own solar heating system.
The eldest of eight siblings, born in Hungary before emigrating to the United States, the scientist was captivated by the immense potential of the sun long before the milestone of the Dover Sun House. During the Second World War, she turned her talents to developing a portable solar desalination kit, a device that ultimately became standard equipment in military survival packs.
“We shall use the sun as a source of energy sooner or later… Why wait?” argued Telkes in 1951, calling for funding to advance nascent research into solar technology. A couple of years later, Telkes, who held a doctorate in physical chemistry from the University of Budapest, secured a grant to develop a solar cooker.
The challenge was to design a simple oven suited to developing nations. Within two years, she had delivered a working unit: “bakes, roasts, and toasts... it does everything but whistle,” as she put it. She gave public demonstrations of the invention: an aluminium box, which featured four fold-out reflective panels that concentrated thermal energy inward. Within half an hour, she had freshly cooked burgers ready to serve. Her fundamental design remains in active use to this day.
Telkes, who died in 1995 in her homeland, blazed a trail for integrating solar power into residential architecture. Today, rooftop solar panels are ubiquitous. Her tireless search for thermal storage solutions anticipated breakthroughs that, decades later, would prove indispensable to the renewable energy transition. The sun, as an inexhaustible and clean source of energy, has ultimately become central to heating and electricity alike. If Telkes could see her legacy today, she would beam like the sun.