In most countries, winter heating is treated as background infrastructure. A thermostat is adjusted, a boiler starts, an electric heater runs, or an air conditioner reverses into heating mode. The room becomes warm, and the family does not think about the power grid, the fuel network, the insulation inside the walls, or the safety systems that make indoor heating ordinary.
In Yemen’s highland cities, winter is different. In Sana’a, Dhamar, Amran, Ibb, Al Bayda, and surrounding areas, cold nights are not rare events. During winter cold waves, temperatures can approach freezing or fall below it in some highland regions. Yet the homes people live in were not designed as thermal systems. They are usually concrete, stone, tile, glass, metal, and air leaks — materials that shelter people from rain and wind but do very little to preserve warmth.
Anyone who has spent a winter night in Sana’a knows that the cold is not only outside the house. It is stored inside the walls, floors, kitchens, bathrooms, and windows. People simply adapt to it because there is no obvious alternative. They wear sweaters inside. They drink hot tea. They sleep under layers of blankets. They avoid moving around the house. Bathrooms and kitchens become especially unpleasant because ceramic and tile surfaces pull heat from the body. Families often gather in one room, not because it is designed as a heated space, but because concentrating bodies is the only heating strategy available.
This is not just discomfort. It is a failure of thermal infrastructure.
Before the war, some households could use electric heating devices when they could afford them. Today, in much of Yemen, the public electricity grid is no longer the main source of household power. Families rely on small solar systems, batteries, and private generator subscriptions. This changes the problem. The issue is not simply that electricity is unavailable. It is that electricity has become too valuable and too expensive to waste on heat.
Electric resistance heating is one of the most power-hungry uses of household electricity. The same solar battery that can run lights, charge phones, power a router, or operate a small appliance can be drained quickly by a heater. A private generator subscription may provide continuous electricity, but at a cost that makes heating a room for hours unrealistic for many families. In this post-grid energy system, electric heating is technically possible for some households but economically irrational for most.
Fuel-based indoor heaters are not a common fallback either. Gas heaters, where they exist, are rare in ordinary homes and not a familiar, widely available appliance in the way they are in many colder countries. For most families, the real fallback is more clothing, more blankets, hot drinks, staying in one room, or simply enduring the cold. In poorer households and rural areas, charcoal or coal is sometimes used indoors for warmth. This is understandable and terrifying at the same time. Charcoal appears simple: it is available, familiar, and produces heat. But in closed rooms, it can produce carbon monoxide and cause suffocation. Every winter, stories circulate of families or individuals who die while trying to stay warm.
The problem is therefore not that Yemen lacks heaters. It is that conventional heating assumes an infrastructure stack Yemen no longer has: stable grid power, affordable electricity, common safe heating appliances, insulated housing, spare parts, and households able to pay for high-energy devices. Yemen’s highland homes need something different: safe thermal survival systems that work under post-grid conditions.
What is needed is not a cheaper electric heater. It is a low-cost way to make one room, or even one sleeping area, thermally livable without continuous electricity, expensive fuel, expert installation, or indoor fire.
Why Heating the Room Is the Wrong Target
The first mistake is to define the problem as “how do we heat the house?” In most Yemeni homes, that is the wrong target.
A typical uninsulated concrete or stone room loses heat through several pathways at once. Heat conducts through walls, floors, windows, and metal frames. Cold air enters through gaps around doors and windows. Tile and ceramic floors draw heat from feet, hands, and bodies sitting close to the ground. Large cold surfaces absorb radiant heat from the body, which is why a room can feel cold even when the air temperature is not extremely low. Concrete and stone also have high thermal mass: once they become cold, they remain cold for hours.
Trying to heat such a room using electricity is inefficient. Much of the heat is absorbed by the building envelope or lost through leakage. Trying to heat it using combustion is unsafe unless ventilation, appliance quality, and user behavior are controlled. In Yemen, none of these assumptions can be guaranteed.
The engineering problem should therefore be reframed: how can we reduce heat loss from people and create a small safe warm zone inside an uninsulated home, rather than attempting to heat the entire building?
This changes the design space. The solution may be a “warm-room kit” rather than a heater: a modular set of low-cost interventions that a household can install without specialists. Its purpose would be to make one room, or one part of a room, meaningfully warmer and safer during winter nights.
A useful warm-room system would have to begin with the least glamorous part of heating: stopping warmth from escaping. In many homes, cold air enters through window gaps, balcony doors, and poorly sealed frames. A practical intervention could be as simple as removable plastic film, fabric seals, rubber strips, adhesive tapes, or locally made wooden or aluminum frames. The challenge is not inventing window sealing; it is designing a version that fits different dimensions, survives dust, repeated use, low-quality surfaces, and installation by non-experts.
The floor is just as important. In many Yemeni homes, people sit, sleep, and move close to tile or ceramic surfaces that draw heat from the body. A low-cost floor barrier — layered mats, recycled textile panels, foam-backed carpets, or modular floor pads — may improve comfort more efficiently than trying to warm the entire room. The goal is not to insulate the whole house. It is to interrupt direct heat loss from the body to the cold building.
The same logic applies to the body itself. Heating the person is often more efficient than heating the room. This suggests body-level thermal design: insulated sitting wraps, sleeping pods, layered blankets with reflective inner surfaces, hot-water thermal packs, or tent-like micro-enclosures inside a room. A small enclosed sleeping or sitting zone can reduce air movement and radiant heat loss without requiring large amounts of energy. The design must avoid condensation, suffocation risk, and social impracticality; it has to fit how families actually sleep, sit, and move.
The safety requirement is equally central. Any design that ignores charcoal will miss the reality of winter behavior, but any design that normalizes indoor charcoal is dangerous. The goal should be substitution, not safer fire: make non-combustion warmth cheap and effective enough that fewer families feel forced to burn charcoal in closed rooms. A responsible design could include carbon monoxide risk education and visual warnings, but the technical goal should remain reducing the need for indoor combustion in the first place.
A Research Program That Could Start Tomorrow
This is not a project that requires a large laboratory. A small team of engineers could begin with measurement rather than invention.
The first missing dataset is simple but important: indoor winter temperature data from real homes in Sana’a and nearby highland cities. Low-cost temperature and humidity sensors placed in bedrooms, living rooms, kitchens, bathrooms, and near floors could show how cold rooms become at night, which surfaces lose heat fastest, and whether one room is naturally easier to protect than another. Outdoor temperature should be recorded at the same time. The goal is to understand the real thermal profile of Yemeni homes, not the idealized version assumed by building models written for other countries.
These measurements should be paired with household interviews. What do people actually do when it is cold? Which rooms do they avoid? How many blankets are used? Do they use electric heaters, charcoal, hot-water bottles, extra blankets, hot drinks, room-sharing, or nothing? What do they fear most: cost, fire, suffocation, battery drain, or appliance failure? How much could a family realistically pay for a winter kit? Without this data, any design is guessing.
From there, the work becomes a practical heat-transfer problem. A simple model of a typical room could estimate heat loss through windows, doors, floors, walls, air leakage, and thermal mass. The point would not be to produce a perfect academic model, but to compare interventions by cost and effect. Does sealing the window matter more than insulating the floor? Does a thermal curtain make a sleeping corner warmer? Is a body-level enclosure more useful than attempting to heat the air? These are answerable questions.
Only after that should prototypes be built and tested. A first set of designs could include window and door sealing kits, floor insulation mats, thermal curtains or room dividers, insulated sleeping or sitting micro-zones, hot-water thermal packs, solar-charged thermal storage, and combined one-room winter kits. Each prototype should be designed for local repair and local materials: fabric, foam, plastic film, rubber, wood, aluminum, recycled textiles, and simple fasteners. It should not require precision manufacturing, electronics, or imported replacement parts. The installation process should be simple enough that a household member can do it without a technician.
The prototypes must be tested in the environment they are designed for. A field trial could compare homes before and after installation, measuring nighttime temperature, floor surface temperature, perceived comfort, electricity use, and whether households reduce unsafe heating practices. A useful target would be a kit that costs less than a small electric heater, requires no monthly fuel or generator cost, and can be repaired with materials available in local markets.
The most important result may not be a dramatic rise in room temperature. Even a modest improvement can matter if it reduces suffering, allows people to sleep more comfortably, or makes families less likely to use charcoal indoors. The system should be judged by thermal benefit per dollar, safety improvement, ease of installation, durability, and whether families actually keep using it after the researchers leave.
Why This Hasn’t Been Done
Heating research is usually written for places with functioning energy systems. Engineers design more efficient heat pumps, better insulation, district heating, smart thermostats, and building energy models. These are important technologies, but they assume a world where electricity, fuel, construction standards, and maintenance systems exist.
Humanitarian winter aid, on the other hand, often treats cold as a supply problem: distribute blankets, jackets, mattresses, or cash assistance. These interventions help, but they do not solve the thermal engineering problem of the home. They keep the person warm for a night; they do not change the heat-loss behavior of the room.
Yemen sits between these two worlds. It is too infrastructurally damaged for conventional heating systems, and too technically specific for generic winter aid. The household has become its own energy system: a solar panel, a battery, maybe a generator subscription, and a careful hierarchy of what deserves electricity. In that hierarchy, heat loses, because heat consumes too much.
That is the core insight: in post-grid Yemen, warmth is not primarily a power-generation problem. It is a heat-retention problem.
The goal is not to make Yemeni homes comfortable by wealthy-country standards. It is to make one room safe enough, warm enough, and cheap enough that families do not have to choose between cold, unaffordable electricity, and dangerous indoor fire.
People in Yemen already know how cold their homes become. What has been missing is the decision to treat that cold as an engineering problem.