The Evidence Behind Upzoning: How Auckland and Minneapolis Proved Building More Housing Lowers Rents

For decades, the global housing affordability crisis has been treated as an intractable economic disease. As rents consume ever-larger shares of household income, policymakers have debated rent control, public subsidies, and demand-side interventions. Yet, a growing consensus of urban economists has continually pointed to a simpler, more intuitive solution: just build more housing.[7]

The core of this argument rests on the laws of supply and demand. If a city builds enough homes to outpace population growth, landlords lose their pricing power, and rents stabilize. However, actually building those homes requires dismantling decades of restrictive zoning laws that made it illegal to build anything other than single-family houses on most urban land.[7]

For years, the debate over "upzoning"—changing the rules to allow denser housing—was largely theoretical. Skeptics argued that upzoning would merely enrich developers, spark land speculation, and accelerate gentrification without actually lowering rents. Today, that debate is being settled by hard empirical data from two massive, city-wide natural experiments: Auckland, New Zealand, and Minneapolis, Minnesota.[7]

The first major test case began in the Southern Hemisphere. In 2016, Auckland adopted its Unitary Plan, a sweeping reform that upzoned approximately 75% of the city's residential land. The plan legalized medium- and high-density housing in areas that had previously been strictly reserved for low-density, single-family homes.[6]

The results of this policy shift were staggering. According to research from the University of Auckland, the Unitary Plan was directly responsible for generating between 22,000 and 43,000 new housing consents over a five-year period. To put that into perspective, the reform boosted the number of consented dwellings by 50% compared to what would have been built under the old zoning rules.[2][6]

This construction boom fundamentally altered the city's housing trajectory. By 2022, Auckland hit a record high of 12 consented dwellings per 1,000 residents. This rate of construction not only reversed a generation-long trend of housing supply lagging behind population growth, but it also allowed Auckland to surpass major Australian states like New South Wales in per-capita home building.[2][6]

The ultimate question, however, was whether this surge in concrete and timber actually helped tenants. The empirical evidence overwhelmingly indicates that it did. Between 2017 and 2024, absolute rents in Auckland increased by 22%. While still an increase, it was significantly lower than the 34% rent growth experienced across New Zealand nationally during the same period.[6]

To isolate the exact impact of the zoning changes, economists utilized advanced "synthetic control" models—essentially creating a data-driven hypothetical Auckland where the upzoning never happened. These models revealed that six years after the Unitary Plan, rents for three-bedroom homes in Auckland were 26% to 33% lower than they would have been in the absence of the reforms.[6]

Half a world away, a similar experiment was unfolding in the American Midwest. In 2018, the Minneapolis City Council passed the Minneapolis 2040 Plan, making it the first major U.S. city to effectively ban single-family-only zoning. The plan aimed to improve affordability by legalizing duplexes and triplexes on every residential lot in the city.[5]

Interestingly, the data reveals that simply legalizing these "missing middle" housing types was not the primary driver of the city's success. The Pew Charitable Trusts found that the duplex and triplex policy had only a modest impact on the housing stock. The failure of missing middle housing to launch was largely due to lingering restrictions on building height and floor-area ratios, which made it economically unviable to convert a single-family home into a triplex.[1]

Instead, the real game-changer in Minneapolis was a combination of two other policies: upzoning commercial and transit corridors to allow for large apartment buildings, and entirely eliminating minimum parking requirements for new developments. By removing the mandate to build expensive parking garages, the city made housing development significantly cheaper and easier.[1]

This targeted deregulation unleashed a wave of multifamily construction. From 2017 to 2022, Minneapolis increased its total housing stock by a remarkable 12%. Because supply finally outpaced demand, rent growth in the city essentially flatlined, growing by just 1% over five years. In stark contrast, the rest of Minnesota added only 4% to its housing stock during the same period, and saw rents jump by 14%.[1]

A 2025 study by economists at Middlebury College confirmed these findings using a synthetic control approach. By comparing Minneapolis to 83 similar donor cities, the researchers found that the 2040 Plan lowered housing cost growth significantly. Over the five years following implementation, rents in Minneapolis were 17.5% to 34% lower than they would have been in the counterfactual "synthetic Minneapolis."[4]

The Middlebury study also highlighted a fascinating psychological mechanism at play. The researchers noted that the price reductions in Minneapolis did not solely stem from the immediate physical completion of new units. Instead, the mere passage of the sweeping zoning reform altered market expectations. The anticipation of future abundance softened housing demand and cooled speculative investment, contributing to the stabilization of prices.[4]

Despite this overwhelming evidence, zoning reform still faces fierce academic and political pushback. Skeptics frequently argue that upzoning data is flawed or that new construction only benefits the wealthy. However, a 2025 peer-reviewed paper by Motu Economic and Public Policy Research systematically reviewed these critiques regarding the Auckland experiment. The researchers found the criticisms to have "little to no merit," concluding that they relied on inappropriate analyses and fundamentally misunderstood the econometric methods used.[3]

It is crucial to acknowledge that upzoning is not a magical silver bullet that instantly makes housing cheap. Housing costs in both Auckland and Minneapolis remain high in absolute terms, and building new units takes years of capital investment and labor. Furthermore, upzoning must be paired with subsidies to provide deep affordability for the lowest-income residents who cannot afford market-rate rents.[2][7]

Nevertheless, the verdict from the data is unequivocal. While it requires comprehensive policy design—such as addressing floor-area ratios and parking minimums alongside density limits—legalizing more housing is a proven, necessary foundation for arresting runaway housing costs.[1][7]

The successes of Auckland and Minneapolis offer a clear, evidence-based blueprint for cities worldwide. By choosing abundance over restriction, municipalities can structurally transform their housing markets, ensuring that future generations have a place to call home.[5][7]