When Emilie Karas purchased a dilapidated home in Portland, Oregon in early 2020, she never imagined it would one day be replaced with a mini-community housing nine people.
Her plan began like any other homeowner’s rebuild and renovate. But midway through the project, Portland passed new zoning laws allowing up to two Accessory Dwelling Units (ADUs) on any residential lot. Then the city went even further: It legalized full-time residency in mobile tiny homes, also known as tiny homes on wheels (THOWs) a hybrid between a camper van and a stationary backyard cottage.
Seizing the opportunity, Karas not only built two stacked ADUs behind her house creating a compact duplex she also added a fully furnished THOW to her backyard, turning her property into an efficient multi-unit haven.
What Are THOWs and Why Do They Matter?
THOWs look like miniature houses charming, self-contained, and often indistinguishable from a fixed cottage unless you notice the trailer hitch beneath them. Built atop 8-by-24-foot steel frames, they’re designed to be mobile and legally classified as vehicles. This classification is what gives them a major edge: they can bypass many of the regulatory hurdles and fees associated with permanent homes.
According to Kol Peterson, a leading Portland-based THOW expert and contractor, the appeal goes beyond minimalism.
“Yes, there’s the philosophy of mobility, downsizing, low environmental impact,” he said. “But fundamentally, it’s about economics THOWs are the only attainable form of housing left for many Americans.”
The Cost Advantage: Night and Day
Karas says installing her THOW was dramatically easier and cheaper than constructing her ADUs. While the ADUs needed concrete foundations and had to meet dozens of building and zoning codes costing six figures the THOW was delivered ready-to-live, with no inspections or city fees required.
She bought the pre-fabricated mobile unit for about $60,000, shipped from Florida, and spent just a few thousand more on setup. Today, she rents it out for $1,200/month, utilities included a rate far below Portland’s average apartment prices.
“It’s a beautiful, safe, and affordable home,” she says. “And while people do have to live in close quarters with others, we’ve built a great community.”
Portland’s Groundbreaking Policy: A National Model?
Most cities in the U.S. still treat THOWs as vehicles, meaning it’s illegal to live in them full-time outside of RV parks or emergency zones. But Portland’s move to recognize THOWs as permanent housing was a bold departure from the norm one that housing advocates say could reshape America’s housing market.
“Portland is proving it’s possible to legalize a radically inexpensive housing type,” said Peterson. “This is a space dominated by homes most people can’t afford. THOWs challenge that.”
How THOWs Stack Up Financially
Building a permanent ADU can easily run between $100,000 to $300,000, not counting land or permitting delays. THOWs, on the other hand, typically cost between $50,000 to $150,000 with no permitting headaches and much faster deployment.
Alan Durning, executive director of the Sightline Institute, a housing-focused think tank in Seattle, believes the affordability gap is too large to ignore.
“When homeowners get quoted $350,000 for a backyard cottage, but could install a THOW for a third of that, the choice becomes obvious,” Durning said.
But there’s one big hurdle: legality. “Most people who want our product,” says Jonathan Palley, CEO of Clever Tiny Homes, “we can’t sell to not because they can’t afford it, but because the land doesn’t allow it.”
Zoning Resistance and Cultural Bias
Cities across America have long resisted mobile and tiny housing especially in affluent suburbs. Jenny Schuetz, VP of housing at Arnold Ventures, says NIMBYism still dominates.
“You’re not going to see snooty Connecticut suburbs allow THOWs anytime soon,” she said. “They’ve resisted even moderate densification.”
Still, during the pandemic, interest in THOWs soared. Jen McCarthy, founder of Canadian builder Teacup Tiny Homes, says the movement has matured beyond just minimalism-loving millennials.
“Now, we’re seeing Gen Xers and Boomers looking to house aging parents or adult children affordably,” McCarthy said.
A Practical Solution for Downsizing or Family Support
Take Julie Lennox, 59, who lives in a THOW parked on her aging parents’ property near Missoula, Montana. After selling her house, she needed a place of her own one she could resell or relocate someday.
“I’m almost 60 with no mortgage,” Lennox said. “I can help my parents and still have independence. It’s been the perfect decision.”
Why THOWs Outshine RVs
While THOWs are mobile like RVs, they’re built with residential-quality materials and aren’t designed for constant travel. This makes them sturdier and more comfortable long-term homes.
Some manufacturers, like Clever Tiny Homes, offer models that start as RV-classified THOWs and can later be converted into permanent ADUs. In wildfire-affected areas of California, Palley is working with clients using THOWs as temporary housing with the flexibility to convert them later.
“You can install it now with minimal red tape,” he explained. “And in a few years, you can certify it as a permanent backyard home.”
A Blueprint for Broader Adoption
Housing advocates in Oregon and Washington are now pushing to legalize THOWs statewide, arguing that they are one of the only scalable, cost-effective solutions to America's affordable housing crisis.
Durning sees them as the natural next step in housing reform.
“If ADUs are the leading edge of infill development,” he said, “then THOWs are the bleeding edge.”
Rethinking the American Dream
With housing costs surging, first-time buyers locked out of the market, and local zoning laws slow to evolve, tiny homes on wheels may represent not just an alternative but a necessity.
In cities like Portland, THOWs are giving homeowners a way to build community, generate income, and offer dignified, beautiful homes to those who need them most. It may be time for more cities to roll with the wheels.
