Affordable housing has become an increasingly dire global issue. Be it rent or homeownership, the unaffordability of homes has been on the rise. A look at U.S. Census data illustrates a sharp decline in homeownership in recent decades. Although Millennials were the most populous generation by 2019, they only contributed to homeownership at a rate of 47.9%. Contrastingly, Gen-X’s homeownership rate stood at 69%, following the silent generation at 77.8%. Trends of generational decline in homeownership are mirrored in other parts of the world, such as in the U.K. where rates have steadily dropped from 71% in 2003 to 64% by 2018. Many experts point to affordability as a large reason for this decline.
Renters haven’t fared better in the affordable housing climate either. The US Department of Housing and Urban Development (HUD) refers to affordable housing as homes that are accessible to a household for 30% or less of its income. By this standard, full-time minimum wage earners cannot afford a two-bedroom apartment in any major U.S. city.
Several factors have led to this affordable housing crisis. First, the increasing cost of labor and materials makes it difficult for developers to invest in and build affordable housing. Secondly, market forces like lowered interest rates can have the unintended effect of driving up the demand within an area with diminished supply, particularly in more desirable urban locations where average home prices are already out of reach for lower-wage earners. Finally, it’s important to recognize how policies at regional, federal and local levels can impact housing patterns and may carry implications for affordability. For example, zoning regulations can influence allowance requirements with minimum setbacks and density controlling regulations, which can dictate the space required for building more housing.
Impact of Climate Change and Climate Migration
Another pressing issue that exasperates the affordable housing problem is climate change. There have been no shortage of recent climate disasters that highlight the heightened risk - the Australian brushfires, the record breaking heatwave in Greece, the path of destruction left behind by Hurricane Ida in the U.S., and the worst flooding on record in Germany - are all climate disasters that occurred within the past two years. The impact of climate change on affordable housing is twofold - the loss of housing stock directly due to damage caused by climate disasters and the migration of people from regions where disasters have struck. This has the effect of raising the costs of housing in climate risk areas due to higher insurance premiums, as well as driving the demand for housing in more temperate regions, thereby increasing costs.
Research suggests that by 2050, rising sea levels caused by carbon emissions could jeopardize 300 million homes worldwide, almost three times what was predicted in earlier data models. This underscores the need for climate positive affordable housing because adverse climate conditions not only have the potential to displace hundreds of millions of people, but it also places additional economic and resource constraints on areas less prone to climate-related disasters. Cities, planning commissions, architects, engineers and designers need to come together to reimagine a solution to address the need for creating more affordable housing in a climate risk environment.
Carbon Positive Housing
One of the innovative ways to address this challenge is to build housing that does not contribute to carbon emissions at all, or even better, that helps generate energy beyond its own needs. Carbon positive housing refers to homes generating an excess of energy beyond their own energy demands (used for heating, insulation, daily electricity consumption, etc.).
Minimizing a building’s energy use with efficient building design is the first step toward carbon positive housing. A building can be optimized for energy efficiency by using appropriate materials (with low embodied energy) and reducing operational and maintenance costs. Incorporating passive design techniques, better insulating materials for heating/cooling (depending on context) and integrating closed-loop systems can make a building energy-efficient and ultimately reduce building loads. Renewable energy systems can then be introduced to address remaining energy needs. Common on-site renewable energy methods can include photovoltaics (PV), solar water heating or wind turbines.
A NetZero Source home built by Habitat for Humanity utilizes envelope efficiency, efficient equipment, appliances and lighting combined with passive and active solar features to achieve its net zero goal. The home uses the utility power grid for storage, delivering energy to the grid when the PV system produces more energy than the home uses and draws from the grid when the PV system produces less energy than the house needs. This approach eliminates the need for battery storage and reduces the cost, complexity, and maintenance of the solar electric system.
In another example, the Charlotte Vermont House is an all electric house that utilizes the sun for passive energy, the earth for mechanical heating and domestic hot water and the wind via a single net metered 10KW Wind Turbine. The house is a documented and verified net energy producer putting more energy back into the grid than it uses for all of its needs, including cooking. As part of the design strategy, it sought to eliminate all fossil fuel burning on site and intentionally chose to use design methods that were the most conventional, in order to make it affordable and replicable.
Affordable Housing Possibilities
The challenges of affordable housing include high construction, labor, and land costs coupled with restricting zoning regulations. To close the supply gap, builders would have to double the amount of housing stock in the next 5-6 years. Focusing on creating secure and affordable housing boils down to quick construction, increasing density and building smaller, more efficient homes. Architects, planners, designers and policymakers have a pressing need to address this through innovative approaches. In evaluating recent design trends, certain types of housing may lend itself to better support affordable housing and sustainability.
1. Modular Housing
A modular home is a house that is near completion when it arrives on-site. Also referred to as prefabricated homes, these homes arrive on-site as multiple elements of the house, which are then assembled on the foundation. This approach of building homes helps in the reduction of costs due to the manufacturing process. The basic version of modular homes can be inexpensive due to their quick construction time and reduced labor cost. A 2000 sq ft modular house could start at $100 to $200 per sq ft. In terms of construction, a modular house uses quality materials and machine built joinery systems, reducing the frequency of annual repair needs. Due to their sturdy nature, these homes are resistant to several types of weather conditions. Furthermore, they can be optimized for energy efficiency with consideration to designing for certain climate conditions, making them environmentally sustainable, energy effective and affordable.
The Swan Housing Association completed an affordable housing project in East London using cross-laminated timber. The work started in late 2018 and by January 2019, 151 modules that were built off-site were transferred on site. The kitchens and bathrooms were installed first, and the electrical and plumbing work were done after. Then the remaining modules were simply laid and dressed by the simple process of connecting them. Due to the modular nature and assembly process of this type of dwelling, the project delivery time was accelerated, reducing the overall labor hours and overall cost of the project.
2. Tiny Homes
According to the US Census, single family homes have been experiencing slow growth ever since 1995. The land crunch has made building mid-size affordable homes difficult. Furthermore, the soaring construction costs have made it impossible for builders to produce affordable single-family homes at the level needed to fill the housing gap. One of the solutions that potentially addresses these issues is the construction of tiny homes.
Tiny homes are independent structures of smaller sizes that can exist solely or alongside a big building. A typical house in the US is approximately 2000 sq ft, whereas a tiny house is usually under 400 sq ft. Emerging from the philosophy of minimalism, tiny homes incorporate several amenities in a small space to ensure comfortable and affordable living for the owner. Many versions of tiny homes are designed to be off-the-grid, making them highly energy-efficient and cost-effective. Due to their small size, they cost a fraction of a traditional on-site house. They can also incorporate several sustainable building techniques and materials and can be made into net-zero or carbon positive homes with the addition of renewable energy capabilities. The use of local or recycled materials in the construction process, for example, can make the embodied carbon footprint of the houses relatively low. An added benefit of their smaller size also means the demand for indoor energy to cool and heat the space is minimal.
3. Manufactured Homes
Manufactured homes are built in the factory, but unlike modular ones, they come completely assembled and only need to be placed on the property. They are regulated by the HUD code and are subject to different rules in different states. Similar to modular homes, these fully-manufactured homes can be cost and energy-effective, reducing the construction cost to half that of a traditional home. Additional measures to improve their energy efficiency can be made by caulking and weather stripping, air sealing, and choosing energy-efficient lighting and appliances. Additionally, manufactured homes may also use sustainable materials, helping in reducing the home’s embodied energy. A big benefit to these types of homes is their scalability, which not only helps builders and developers build homes and whole communities more quickly, but they can also do so at a considerable cost advantage.
The Path to Affordable Carbon Positive Housing
All these new possibilities for rethinking affordable homes can be optimized for climate resiliency and be carbon positive buildings. They can be designed to be a part of the circular economy by reducing and reusing waste and be used as sustainable alternatives themselves with energy efficient principles. By leveraging innovative methods of design and technology, these buildings can perform better, help manage their energy needs and possibly generate energy themselves.
Two achievable ways to scale inexpensive carbon positive housing is through data-driven decision making and introducing repeatability into the process. Conventionally, climate and site analysis have been conducted manually by architects and designers to understand the context of their designs and to make design decisions to help make a building more energy efficient. This process is manual and time consuming and can add to project costs. Using an automated performance analysis tool can help accelerate the project timeline, allowing designers to select better materials and optimize design choices with sustainability targets in mind. Using advanced energy analysis tools, for example, can ensure that energy efficiency measures are always built into projects. This can include design strategies that reduce the demand-side loads such as high-performance envelopes, air barrier systems, daylighting, sun control and shading devices, careful selection of windows and glazing, passive solar heating, natural ventilation, and water conservation. Once overall building loads are reduced, careful consideration for efficient equipment and systems should be made. This may include energy efficient lighting, electric lighting controls, high-performance HVAC, geothermal heat pumps, or energy conversion devices.
As with the Charlotte Vermont house example, intentional design strategies and methodologies that bear in mind repeatability are key to creating affordable and sustainable homes that have the potential to be built at scale. When combining that philosophy with tools and technologies that can help accelerate those decisions and guide designers toward smarter design choices, it opens up the possibilities for addressing affordable housing and climate change.
To truly reimagine the possibilities for affordable and sustainable housing, architects, engineers, policymakers and stakeholders have to work together toward a common vision. Thoughtful policy and thoughtful design need to converge in order to address the complex issues of affordability and sustainable housing in a climate risk environment. Housing types like modular homes, manufactured homes and tiny homes offer possibilities for constructing affordable homes at scale, but it cannot happen in isolation. Innovative design and technology paired with carefully crafted policy and the right incentives are needed for the development of more sustainable and affordable communities.