The tiny-house movement (also known as the "small-house movement") is an architectural and social movement that advocates living simply in small homes. 2018 International Residential Code, Appendix Q Tiny Houses defines a tiny house. However, a residential structure under 400 square feet (37 m2) is generally considered a tiny home. The tiny-house movement promotes financial prudence, economically safe, shared community experiences, and a shift in consumerism-driven mindsets.
In the United States, the average size of new single family homes grew from 1,780 square feet (165 m2) in 1978, to 2,479 square feet (230.3 m2) in 2007, and further still to 2,662 square feet (247.3 m2) in 2013. Increased material wealth and individuals with high incomes are common reasons why homes sizes increased.
The small house movement is a return to houses of less than 1,000 square feet (93 m2). Frequently, the distinction is made between small (between 400 and 1,000 sq ft or 37 and 93 m2), and tiny houses (less than 400 sq ft or 37 m2), with some as small as 80 square feet (7.4 m2).
Henry David Thoreau and the publication of his book Walden are often quoted as early inspiration. The modern movement is considered by some to have started in the 1970s, with artists such as Allan Wexler investigating the concept of choosing to live in a compact space. Early pioneers include Lloyd Kahn, author of Shelter (1973) and Lester Walker, author of Tiny Houses (1987). Sarah Susanka started the "counter movement" for smaller houses which she details in her book The Not So Big House (1997).
Tiny houses on wheels was popularized by Jay Shafer who designed and lived in a 96-square-foot (8.9 m2) house and later went on to offer the first plans for tiny houses on wheels, initially founding Tumbleweed Tiny House Company, and then Four Lights Tiny House Company on September 6, 2012. In 2002, Shafer co-founded, along with Greg Johnson, Shay Salomon and Nigel Valdez, the Small House Society. Salomon and Valdez subsequently published their guide to the modern Small House Movement, Little House on a Small Planet (2006) and Johnson published his memoir, Put Your Life on a Diet (2008).
With the Great Recession hitting the world's economy in 2007-9, the small house movement attracted more attention as it offered affordable, ecologically friendly housing. Overall, it represented a very small part of real estate transactions. Thus, only 1% of home buyers acquire houses of 1,000 square feet (93 m2) or less. Small houses are also used as accessory dwelling units (or ADUs), to serve as additional on-property housing for aging relatives or returning children, as a home office, or as a guest house. Tiny houses typically cost about $20,000 to $50,000 as of 2012.
Tiny houses have received considerable media coverage including a television show, Tiny House Nation, in 2014 and Tiny House Hunters. Bryce Langston from New Zealand created and hosts a YouTube channel that features international tiny homes and eco-friendly living, called Living Big in a Tiny House  Tiny houses on wheels are often compared to RVs. In Canada and the United States, these are called park model RVs if they do not exceed certain size specifications, namely 50 m2 (540 sq ft) in Canada/400 sq ft (37 m2) in the United States). However, tiny homes are held to state/provincial/territorial building codes. Park model RVs are held to standards set by the Standards Council of Canada or RV Industry Association (RVIA). Tiny houses are built to last as long as traditional homes, use traditional building techniques and materials, and are aesthetically similar to larger homes.
While the movement is most active in America, interest in tiny homes has been observed in other developed countries.
The popularity of tiny houses has led to an increase in amateur builders which has raised concerns regarding safety among tiny house professionals. In 2013, the Tiny House Fair at Yestermorrow in Vermont was organized by Elaine Walker. An attendee at the event, Jay Shafer, suggested promoting ethical business practices and offering guidelines for construction of tiny houses on wheels. Walker continued this effort in 2015, creating the non-profit organization, American Tiny House Association.
One of the biggest obstacles of the tiny house movement is the difficulty in finding a place to live in one. Zoning regulations typically specify minimum square footage for new construction on a foundation, and for tiny houses on wheels, parking on one's own land may be prohibited by local regulations against "camping."  While tiny houses do save on some costs, they can still be expensive depending on the cost of the land they occupy.
In addition, RV parks do not always allow tiny houses unless they meet the criteria required for RVs. Tiny houses on wheels are considered RVs and are not suitable for permanent residence, according to the Recreational Vehicle Industry Association. From RV Business, "The RVIA will continue to shy away from allowing members who produce products that are referred to as "tiny houses" or "tiny homes". (However, the RVIA does allow “tiny home” builders to join as long as their units are built to RV or park-model RV standards.)" 
Lower court decisions in the US have struck down zoning laws related to size that were an obstacle to tiny housing. One of those cases was League of South Jersey, Inc v. Township of Berlin, where the court found that a zoning law related to the size of a home did not protect citizens, so the law was struck down. These decisions are still far from being the majority, but they help in allowing the propagation of the tiny housing movement.
In 2014, the first "tiny house friendly town" was declared in Spur, Texas; however, it was later clarified that a tiny house may not be on wheels but must be secured to a foundation.
In July 2016, Washington County, Utah revised their zoning regulations to accommodate some types of tiny houses.
Increasingly, tiny houses have become larger, heavier, and more expensive. The ideal of minimal impact on the environment is not a priority for all home-owners as businesses capitalize on the popularity of tiny homes.
Tiny houses have been noted as impractical spaces to raise families in. Overcrowding and lack of space have been noted to be detrimental to both physical and mental health, and can affect school performance.
The financial crisis of 2007–08 fueled the growth of the small house movement. In several cities, an entrenched homeless population formed around "tent cities" or encampments that became semi-permanent housing. Homelessness in these communities was driven by foreclosures and expensive mortgages from the United States housing bubble.
Tiny houses became an affordable option for individuals who lost their homes. With their low cost and relative ease of construction, tiny houses are being adopted as shelters for the homeless in Eugene, OR; Olympia, WA; Ithaca, NY; and other cities. Communities of tiny houses offer residents a transition towards self-sufficiency. Communities such as Othello Village in Seattle, WA, originally lacked electricity and heat. In Seattle, non-profits have stepped in to help provide amenities.
Housing the homeless is said to be a cost-saving for municipalities. The long-term viability of tiny houses for homeless people is completely dependent on the structure and sustainability of the model. Strict zoning and land ownership laws make it difficult for this movement to take root. Benefits of access to housing include privacy, storage, safety, restoration of dignity and stability.
In Reno, Nevada, faith-based groups and community advocates have legislated new zoning for housing of homeless people in a tiny home community. Each tiny house would cost an estimated $3,800 to build, as well as an operating budget of $270,000 for case managers to help residents find more permanent housing and a project manager position.
One challenge besides zoning and funding has been a NIMBY response by communities. Communities may weigh concerns over tiny home communities becoming shantytowns or blighted neighborhoods that reduce property values of the surrounding neighborhoods. For cities such as Chicago, tiny houses are seen as an appealing option to close the gap in housing availability. Community planners also have concerns that communities don't devolve into shantytowns such as during the Great Depression in "Hoovervilles".
In California, the city of Richmond has engaged University of California-Berkeley students in the THIMBY (Tiny House In My Backyard) project with a pilot program for developing a model of six transitional tiny homes to be placed in the city. This is in-line with developing efforts in the San Francisco Bay Area to use micro-apartments and tiny houses in combating the housing crisis and Homelessness in the San Francisco Bay Area. Similar efforts of using tiny houses to house the homeless are also ongoing in Oakland through a partnership between the City of Oakland and Laney College.
In Edinburgh UK the Social Enterprise Social Bite asked Jonathan Avery of Tiny House Scotland to design a variation of his NestHouse tiny house to create a two bedroom version for its Homeless Tiny House Village in the Granton area of Edinburgh. The village was opened on May 17, 2018 by the Scottish Cabinet Secretary for Communities, Social Security and Equalities, Angela Constance MSP and features eleven NestHouse Duo tiny houses and a community hub building all built by Carbon Dynamic.
In the co-authored research article The Psychology of Home Environments, it's argued that the drive behind the tiny house movement is centered around desires of modesty and conservation, in addition to environmental consciousness, self-sufficiency, and wanting a life of adventure. In building tiny houses, there is often a misalignment between the needs of the occupant(s), and the expressed design from the creating team. This reality is used as a call for architects and design teams to work with psychologists to build tiny homes that are better suited towards the needs of the occupant(s). In understanding these considerations, it is important to note that not everyone is suited for a tiny house.
Smaller homes are less expensive than larger ones in terms of taxes and building, heating, maintenance, and repair costs. The lower cost of living may be advantageous to those with little savings, such as people aged 55 and older. In addition to costing less, small houses may encourage a less cluttered, simpler lifestyle, and reduce ecological impacts for their residents. The typical size of a small home seldom exceeds 500 square feet (46 m2). The typical tiny house on wheels is usually less than 8 by 20 ft (2.4 by 6.1 m), with livable space totaling 120 sq ft (11 m2) or less, for ease of towing and to exempt it from the need for a building permit.
Small houses may emphasize design over size, utilize dual purpose features and multi-functional furniture, and incorporate technological advances of space saving equipment and appliances. Vertical space optimization is also a common feature of small houses and apartments. An example of this is the use of loft spaces for sleeping and storage. Because of overall height restrictions related to the ability to easily tow a tiny house, it is common for lofts to be between 3.3 ft and 5.5 ft (1.0m and 1.7m) inside height. Therefore, for accessibility of elderly and disabled people, larger floor plans that keep essential elements like bed, bathroom and kitchen on the main floor are more typical.
The increased utilization of small houses as second homes or retirement houses may lead to development of more land. People interested in building a small home can encounter institutional “discrimination” when building codes require minimum size well above the size of a small home. Also, neighbors may be hostile because they fear negative impacts on their property values and have concerns about increased taxes.
Tiny homes are threatening increased grid defection because of their inherently low energy demands due to their small size. Their customized builds and smaller energy demand often lend themselves toward dependence on rooftop photovoltaics such as roof-mounted solar panels. Especially with the continuously decreasing price of solar panels and batteries, tiny homes are examples of existing and commercially proven alternative off-grid housing.
Each space and house will have their own energy consumption profile and generation demand. Consequently, they must size their power equipment accordingly. The needed size of battery systems to store captured energy or grid-supplied energy that will be used during times without power production from the rooftop solar, such as when there is inadequate insolation, depend on the generation capacity (as to not under or oversize the battery bank), the type of batteries used, their individual capacity (A⋅h), the discharge rate allowable per cycle (%), the size of loads (W), how long they will be run, and how many days of storage are needed. Battery sizing calculators are available online to simplify this process. Additionally, battery balancers, sensors that can read and recalibrate the available capacity, or state of charge, between different battery cells, can be added to extend the life of a battery system to prohibit voltage offset or non-ideal current flow, potentially damaging or capacity reducing to batteries over time. Batteries are rated in terms of ampere-hours with their discharge rate and capacity set by the manufacturer at a specific current and total amount of time, as voltage differs with temperature and power will vary with rate of discharge.
To fully convert a tiny home for living capacities off-grid, other power electronic power equipment is necessary, such as a charge controller, an inverter to power AC loads or down-regulators for DC loads, and proper protection devices such as circuit breakers and fuses. Specific sine inverters may offer simultaneous grid power hookup, called “grid-tie inverters” in case of insufficient energy generation locally. Grid-tie inverters are of academic interest and are being studied by utilities for their impacts and potential benefits to voltage regulation, infrastructure implications, protection schema requirements, economics, and optimum policy regarding integration for implementation into the electrical grid with the rise of distributed generation, namely residentially supplied solar power.
Tiny homes range typically between 100 and 400 square feet (9.3 and 37.2 m2). Considering the small size of tiny homes in comparison to that of average-sized homes, energy costs are invariably smaller; moreover, tiny home power grids are typically sourced from solar panels, which decreases the amount of publicly produced energy necessary to sustain the home. More importantly, the price difference of using solar power on a tiny home in comparison to an average-sized home, not decrease significantly the homeowner expenses. Thus, the variation of energy emissions and cost necessary for output between a tiny home and average-sized home varies notably. While a tiny home is sustained to operate on 914 kilowatt hours a year, producing on average 1,144 pounds (0.519 t) of carbon dioxide, an average-sized house requires 12,733 kilowatt hours, which releases close to 16,000 pounds (7.3 t).
Consequently, tiny homes inevitably require the consumption of less energy to support the homeowner. As a result, people living in tiny homes typically limit the accumulation of materialistic items. The limited space of a tiny home insists that owners sacrifice the idea of abundant materialism. It also allows homeowners to re-evaluate their personal habits, which subsequently translates into awareness regarding environmental sourcing. The concept of a “tiny” home reflects all aspects of the chosen lifestyle; a minimized space necessitates minimal consumer spending while the limited amount of surface area provided decreases the rate and level of energy consumption.
Human beings have been the main contributors in recent environmental changes. One critical proponent of these changes relates to infrastructure; buildings affect both human beings and the environment. However the costs tend to effect the environment while the benefits are exclusive to humans. The intention of building new infrastructure is to guarantee its sustainability for a long period of time. As a result, the less environmentally intentional a facility is, the more it will depend on consumption of natural resources. “Part of the very definition of a tiny home is that it be constructed with environmentally conscious and renewable materials.” Most tiny homes are designed to receive their services in ways that are less environmentally exhaustible. Electrical grids and public utilities are a distinguishable way tiny homes receive various water, electric and plumbing services. This detail is critical for consideration when individuals move from average sized homes to tiny homes because it allows individuals to both save money while using less environmental resources. Another important environmentally conscious feature relates to toilets. Some tiny homes are equipped with incinerator toilets which get rid of waste by burning it rather than flushing. By eliminating toilet flushing, the amount of water used in a household significantly decreases. An alternative feature is a compost toilet which works by decomposing the waste using evaporation to remove it. Therefore, not only are tiny homes energy efficient, the makeup of these homes are also intended to be environmentally friendly. Subsequently, in order for new materials to be both utilized in construction and sustainable for long periods of time, the production of such materials are dependent on various chemicals; this added step removes additional resources from the environment. An alternative to this is the usage of recycled materials which reduces the need for added chemicals because the process of which has already occurred in the initial production. For example, the tiny homes designed by a group in Texas, consciously avoid using new materials in their construction. Bearing in mind the fact that human beings expend between 30-40% of all energy, infrastructure is best fit to include the consumption of human beings within its blueprints.
Those individuals who live in tiny homes are directly connected to the environment primarily because of the close proximity between tiny homes and the surrounding ecosystems. Through constant contact, the homeowner is given the opportunity to better understand the functions of nature. Such an understanding allows for an increase in environmental awareness.
More so, the design of tiny homes are subject to individual modification; the style, level of sustainability, intricacy, materials used, and modifications are all determined by homeowner preferences.
Homelessness is a critical issue in the United States. According to The U.S. Department of Housing and Urban Development, about 550,000 individuals were experiencing homelessness on a given night in 2018. Over half of those individuals were able to sleep in different types of shelters while roughly thirty-five percent were unable to reside in a sheltered area. Despite the little information provided on this issue in popular media, homelessness has the capacity to affect the environment dramatically. According to the Environmental Council of Sacramento, homelessness is a contributor to environmental deterioration. For example, waste [litter, drug paraphernalia, etc.] produced by the homeless accumulates around their living spaces which tend to be near waterways, sewage systems, or parks. This leads to the contamination of the surrounding ecosystem. The Environmental Council offers steps towards conserving the environment while simultaneously dealing with the issue of homelessness. These steps include the cleaning of various water systems and public spaces in order to provide both clean water and clean areas for all individuals of the community. One of these steps also includes governmental intervention in establishing sanitary and safe spaces for the homeless in order to prevent further environmental destruction. Luckily, systems for just that are beginning to form though the tiny house movement.
A critical form of combating chronic homelessness is the establishment of tiny house communities. Those behind such establishments aim to help individuals solve their housing problems and offer a space where individuals can connect with others who find themselves in similar circumstances. Creating these communities requires a variety of support, however the end goal is ultimately shared. The primary actors behind the building and funding of tiny homes for the homeless are non-profit organizations. Their goal is not only to give homeless people a place to live, but also offer them resources to help them in all aspects of their lives. Building communities of tiny homes for the homeless is a group effort involving the homeless, cities themselves, and housing patrons. Through their efforts, the issue of homelessness in itself, along with its effects on the environment, are being continuously combated and improved.
By placing greater emphasis on quality living, personalization, an environmental ethic, and community values, the tiny house subverts the consumer-based mindset. Culturally, what the tiny house does is simple: it creates an opportunity outside the norms of society where people can understand that the value of the environment and human interaction is much greater than the value of material goods.