According to Michael Andersen at the Bike Portland blog, tiny homes (or ADUs, accessory dwelling units) now make up about three percent of new dwellings in the city of Portland, with one in ten new homes considered 'tiny.'
These living spaces of 800 square feet or less are tucked into backyards, built on wheels and ready to be towed around to their resting grounds, or made-over from old garages.
In Andersen's blog article Eric Engstrom, the city of Portland's lead planner around ADUs, says that in some inner city neighborhoods as many as 10 to 15 percent of new dwellings are these smaller homes. While 800 square feet might seem enormous to bigger-city dwellers (Graham Hill's small-is-beautiful Life Edited apartment is just 420 square feet) most of the existing housing stock in Portland is larger single-family homes.
In the U.S. Portland took an early lead in encouraging people to build and to re-model and bring up to code smaller living spaces. It is part of Portland's long-running plan to avoid sprawl and fill-in emptier spaces in the urban core instead of watching farmland on the fringes turn to suburban housing developments. Permitting costs are waived for ADUs in Portland through 2016.
Recently it has felt in Portland like apartment building has gotten out of hand. Last year 3,000 new rental units went on the market, and this year 7,500 more are expected to be finished as well as another 7,500 done in 2015. Yet, still, Portland has the second tightest rental market in the U.S., with a rental vacancy rate of under 3 percent. And 75,000 people moved to the city in 2013.
That makes building or re-modeling a tiny home or ADU an attractive proposition. ADUs in Portland tend to have lower energy costs over time because of a lower ratio of square feet per inhabitant than average homes; many ADUs because of their size don't even both with a conventional heat source.
Tiny homes can have drawbacks - they are not entirely cheap to build (Portland's ADUs are estimated to cost $80 to $100K to build new) - and if they are on wheels, they still always need a parking place. But in true Portlandia fashion, they are currently all the rage in my town.