It is encouraging indeed that seven real-estate developers were interested in building efficiency apartments in Kakaako with low monthly rents, and that the Hawaii Community Development Authority has deemed three proposals strong enough to move forward as finalists for the project.

All three finalists’ proposals far exceed the HCDA’s minimum requirements to build at least 50 dwellings on the 10,409-square-foot lot the agency owns at 630 Cooke St. One proposes 104 micro-units in a 17-story tower; another offers 109 micro-units in a nine-story building; and the third would build 93 micro-units in a 12-story building.

The apartments are small by design, intended to appeal to solo occupants or couples that will accept tight quarters for low rent. Most of the apartments would be about 300 to 350 square feet, and the rent could run from about $400 a month for the lowest-income tenants to less than $1,000 a month for those on the higher end of the income eligibility scale.

Studio apartments of this size are the norm in places such as New York City and San Francisco, major cities that like Honolulu have limited room to grow. They are perfectly suited for Oahu’s urban core, especially as the population ages and the number of solo-occupant households increases. Small units containing a kitchenette, bathroom and a small living and sleeping nooks are livable long term, as single urbanites throughout the United States have long demonstrated.

All three finalists — which include a partnership between California-based nonprofit EAH Housing, an affordable-housing developer active in Hawaii, and New York-based Bronx Pro Group LLC; local real-estate developer Stanford Carr; and local nonprofit affordable-housing developer Mutual Housing Association of Hawaii — offered plans containing a mix of units that would have monthly rents affordable for people earning up to 60 percent of Honolulu’s area median income, or $40,300 for a single person.

It’s also reassuring to note that all three developers have experience developing subsidized housing that depends on a complex combination of financing and tax credits to bring to fruition.

As the HCDA narrows down its decisionmaking to choose the successful bidder, it should focus not only on the number of units offered, but also on which proposal fits best into the neighborhood, one that is rapidly being gentrified and is already zoned for buildings up to 400 feet.

In its initial request for proposals, the HCDA also emphasized the desire to reduce traffic congestion and encourage the use of mass transit, especially considering that the building would be close to the coming rail-transit system, which will run along Halekauwila Street. Proposals that achieve that and incorporate the concept of car-sharing to reduce the number of needed parking spaces merit extra consideration.

Likewise, construction plans that emphasize "supportive housing" programs that assist elderly or disabled tenants deserve special consideration, as the micro-units building should appeal to needy people who, absent this option, might fall into homelessness.

Whenever income limits are applied to attractive, subsidized housing, there is always the possibility that unintended consequences will occur: Once ensconced, tenants may lose the incentive to earn more money, or fail to disclose the money they do earn, to avoid losing the cheap apartment.

This is a potential pitfall to be avoided, to be sure, as the most sustainable society is one that expects all able-bodied, able-minded adults to work and support themselves.

But the truth is that there already are many hardworking adults in Honolulu who meet these income restrictions, not to mention retired senior citizens, so there is little risk a micro-unit housing development like this will be abused. Honolulu is such an expensive place to live that there likely will be no shortage of eligible tenants who remain eligible year after year, even though they are working.

With these three promising development proposals, the HCDA has the opportunity to make a strong choice that paves the way for a viable new lifestyle in Honolulu’s urban core.