Air Conditioning: From Luxury to Lifesaving Necessity
How climate change transformed air conditioning from a comfort feature into a public health essential—and why our response matters.
The climate crisis is upending once-stable assumptions about how we live, work, and build our homes. Decades ago, air conditioning was seen as a luxury—even a symbol of extravagance. Today, as summers grow hotter and extreme heat shatters records worldwide, air conditioning has become a matter of survival for millions. Yet this necessary adaptation brings urgent new questions about energy, equity, design, and the future of our built environment.
Why Air Conditioning Became a Necessity
Throughout much of the 20th century, air conditioning (AC) was optional—something extra for businesses, affluent families, or those in the sunbelt. But the world is not what it used to be. Year after year, cities from Vancouver to Portland, New York to Delhi, break heat records and see dangerous heat waves claiming lives. Authorities now distribute air conditioners to vulnerable populations and open cooling centers to the public. In this new reality, going without AC is not merely uncomfortable—it can be fatal for the elderly, infants, and people with health vulnerabilities.
- Older housing stock and infrastructure were originally built for milder climates, often relying on natural ventilation, shading, and orientation.
- Modern homes and apartments, especially high-rise glass buildings, often lack effective passive cooling options, trapping heat inside during extreme weather.
- Climate change has shifted long-term weather patterns, making heat waves more intense and persistent—even in traditionally cool regions.
A Brief History: When Passive Cooling Was Enough
Before the era of widespread air conditioning, home design varied dramatically by region. Builders and architects drew on generations of local knowledge to keep buildings habitable:
- High ceilings allowed hot air to rise above occupied space.
- Big, operable windows and transoms promoted cross-ventilation during hot nights.
- Porches, deep eaves, and shade trees kept direct sun off walls and windows.
- Building orientation and materials acknowledged the climate—thick masonry in the South, breezeways, and shaded courtyards.
As one architectural historian noted, Thomas Jefferson’s Monticello took advantage of its hilltop location and large windows to harness cooling breezes, while the structure’s brick walls delayed interior heat gain until cooler nighttime hours. These “passive” strategies offered comfortable—and sustainable—living long before mechanical air conditioning existed.
How Air Conditioning Changed Architecture and Expectations
The post-war boom in air conditioning, especially from the 1950s onward, marked a pivotal shift. With the turn of a dial, it became possible to live comfortably in nearly any building—anywhere—regardless of its siting, orientation, or insulation. This revolutionized home-building in both good and bad ways:
- Builders no longer designed houses to suit regional climates; instead, “one-size-fits-all” styles proliferated from coast to coast.
- Porches, operable windows, and shading devices fell out of favor, replaced by sealed boxes reliant on mechanical cooling.
- The fossil fuel-powered “convenient climatic package” offered near-total control of indoor temperature and humidity—at a hefty cost to the environment and to electricity grids.
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This shift meant that people could, in theory, live behind uninsulated walls in the desert, in glass towers in northern latitudes, or under low ceilings in the humid tropics—if, and only if, the AC kept running.
Environmental and Social Costs of Air Conditioning
As much as air conditioning can save lives in extreme heat, it is not a straightforward solution. The climate and grid impacts are profound:
- Most air conditioners run on electricity derived from fossil fuels, creating an intensifying cycle: more AC demand means more greenhouse gas emissions, which in turn drive greater climate change and even hotter summers.
- During heat waves, power grids often approach or exceed their limits, leading to brownouts and blackouts precisely when cooling is most needed.
- AC units expel hot air into the environment, exacerbating the urban heat island effect, where cities become several degrees hotter than surrounding regions.
- Equipment costs, repairs, and maintenance can prove prohibitive for low-income families, creating disparities in who remains safe during heat emergencies.
In some regions, progress is being made: Canadian provinces like Ontario, Quebec, and British Columbia rely largely on hydroelectric and nuclear power—much lower-carbon sources. Yet even there, gas-fired “peaker” plants often spin up during summer heat waves to meet spikes in demand, boosting carbon emissions just when the world is trying to reduce them.
Designing for Survival: Passive Cooling Then and Now
The growing reliance on AC is, in many ways, an indictment of modern building design. Passive cooling strategies once allowed people to survive and even thrive through summer’s worst. Reviving and adapting these approaches is critical, both for reducing energy costs and for providing a “resilient design”—one that can keep people safe when the power goes out.
- Shading: Exterior shades, shutters, and overhangs dramatically reduce indoor heat gain. In Europe, exterior blinds are ubiquitous and used strategically: left open at night to flush out hot air, closed during the day to block sun and heat.
- Cross-ventilation: Purposeful placement of windows to capture breezes, coupled with high ceilings, lets hot air escape naturally.
- Thermal mass: Materials like stone, brick, and tile absorb heat during the day and release it at night, smoothing out temperature swings.
- Building orientation: Siting the home to catch prevailing breezes and shield against afternoon sun remains effective in many climates.
Yet, as multiple studies confirm, these strategies are often no longer sufficient on their own. When outdoor temperatures stay above 80°F (27°C) overnight, shading and ventilation cannot reliably keep interiors safe without mechanical assistance, especially in high-density buildings.
The Challenge of Modern Apartment Buildings
Today’s multifamily buildings—especially those with extensive glazing, thin walls, and high occupancy—present special challenges.
- More people in tight quarters mean more cooking, showers, and electronic devices—all of which add to internal heat gain.
- High-rise apartments, particularly on upper floors, become heat traps as hot air rises and solar exposure increases. After splitting a traditionally-designed house into two units, owners sometimes find the upper floors uninhabitable without AC.
- Buildings with little to no exterior shading or cross-ventilation become dangerous during power failures, as heat accumulates and night cooling is ineffective.
Experts now recommend that even when passive strategies are used, buildings be designed from the outset with the capability to add mechanical cooling later, ensuring safe conditions as the climate continues to change.
Heat Pumps and High-Efficiency Alternatives
There has been a surge of enthusiasm for heat pumps—high-efficiency appliances that provide cooling in summer and heating in winter. However, heat pumps are not a panacea:
- Heat pumps are, functionally, still air conditioners in hot weather and require thoughtful sizing and load management.
- Their efficiency and climate benefits depend heavily on the source of electricity; where grids are fossil-fueled, they may still contribute significantly to emissions.
- Older refrigerants used in many AC and heat pump systems are powerful greenhouse gases. Next-generation low-carbon refrigerants are essential for curbing indirect climate impacts.
- Reducing the cooling load—through better insulation, smaller windows, improved shading, and ventilation—remains crucial for system sustainability and resilience.
Shifting Our Building Priorities
The drive for the maximum amount of glass, huge windows, and open floor plans has created buildings that are visually appealing but thermally vulnerable. Instead, designers and homeowners must balance:
- Energy efficiency: Use high-performance glazing, airtight construction, and robust insulation to minimize unwanted heat gains and losses.
- Quality of life: Position windows for natural views and daylight, but supplement with shading—not just for aesthetics but for survival.
- Mechanical ventilation: In tightly-sealed homes, integrate heat-recovery ventilation systems to maintain fresh air without sacrificing efficiency.
- Solar control: Use smart façades, adjustable overhangs, or dynamic blinds to optimize the balance between light, heat, and comfort throughout the year.
Equity and Air Conditioning Access
The necessity of air conditioning reveals and widens social divides. As the cost of AC installation and electricity rises, wealthier households stay cool while low-income and elderly people may be forced to endure dangerous heat. Community interventions, such as government-funded AC distributions and cooling center programs, are increasingly common in cities facing sustained heat emergencies.
- Public policies must ensure that the most vulnerable populations—older adults, children, disabled people, and those in poorly insulated housing—can access safe cooling during extreme heat events.
- Long-term resilience depends on upgrading existing housing stock and strict standards for new construction, with both passive and active cooling considered as essential services.
The Way Forward: Building for a Hotter World
Air conditioning’s rise to necessity status is not an endorsement of building the same way and simply plugging in more machines. The world must adapt in multiple, overlapping ways:
- Retrofit and design buildings for passive survivability: Even in blackouts or grid failures, well-designed homes should not become death traps.
- Phase out fossil fuel-based electricity and transition grids to renewables, so that mechanical cooling does not worsen the climate crisis.
- Accelerate innovation and deployment of efficient, low-carbon cooling technologies.
- Legislate and enforce building codes that mandate both thermal performance and adaptability for future climate extremes.
- Educate architects, builders, and homeowners about critical passive strategies—applying the lessons of traditional architecture to contemporary challenges.
In the end, air conditioning is now a public health tool, an equalizer, and a climate adaptation measure. Used wisely, with high-efficiency machines and low-carbon power, in buildings that minimize their cooling needs, it can keep us safe. Used indiscriminately, it may propel us further into the crisis.
Frequently Asked Questions (FAQs)
Q: Is air conditioning bad for the environment?
A: The environmental impact of air conditioning depends on the local electricity grid, the efficiency of the units, and the type of refrigerant used. Systems running on fossil-fuel electricity and outdated refrigerants contribute significantly to greenhouse gas emissions and urban heat.
Q: Can passive cooling alone keep homes safe during extreme heat?
A: While passive cooling strategies—shading, cross-ventilation, thermal mass—were sufficient for much of the 20th century, rising nighttime temperatures in many regions now mean that these alone are often not enough during extended heat waves, especially in dense urban settings.
Q: Are heat pumps a better alternative to traditional air conditioners?
A: Heat pumps are more energy-efficient than traditional ACs and can provide both heating and cooling. However, their sustainability is linked to the carbon intensity of the local grid and the refrigerants they use. Improved building envelopes (insulation, windows) are still necessary to minimize energy use.
Q: What are the best ways to reduce the need for air conditioning at home?
A: The best strategies include adding external shading (awnings, shutters), planting shade trees, sealing and insulating your home, using energy-efficient windows, and orienting new buildings to maximize passive cooling. Retrofit or design for mechanical cooling as a backup for extreme heat events.
References
- https://lloydalter.substack.com/p/air-conditioning-is-a-hot-topic-these
- https://lloydalter.substack.com/p/why-we-need-windows-with-purpose
- https://tedium.co/2019/07/09/air-conditioning-architecture-impact/
- https://www.canadiancontractor.ca/voices/comment-about-bleasbys-article-kicking-our-addiction-to-a-c/
- https://www.asthmaandallergyfriendly.com/USA/the-8-best-small-fans-of-2021/
- https://www.sciencenews.org/article/why-tree-hugger-koalas-are-cool
- https://www.media.mit.edu/articles/material-ecology-additive-technology-and-biological-forms-2/
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