There are about 7,000 public school classrooms with no air conditioning in Hawai'i, some of them so oppressively hot and uncomfortable that students struggle just to stay alert. The Department of Education announced its new plan to study this chronic problem and come up with solutions. It's the third study in six years, and the most sensible thus far.

But it also underscores the fact that the DOE still doesn't have a solid grasp of the scope of the problem systemwide. That needs to change quickly, so solutions can be implemented sooner rather than later.

The latest plan comes after the DOE reevaluated a strategy adopted by the Board of Education six years ago, which focuses on installing central air conditioning at the state's hottest schools. But which ones are the hottest?

The DOE conducted two previous studies — the first one flawed, the second more accurate — that ranked the state's 258 public schools by temperature and comfort level. Midway through the second study, the DOE realized some serious weaknesses in its approach. First, a school's ranking didn't accurately reflect conditions in individual classrooms. And installing central air in every school, one by one, would be astronomically expensive. One estimate put the cost around $1.5 billion.

Since the Legislature allocated just $8 million over the next two years for noise and heat mitigation in classrooms, the DOE found itself grappling with a six-year-old premise that Randy Moore, assistant DOE superintendent, described as "suboptimal."

So now the DOE must build a new list, one based on precise measurements taken in individual classrooms at all the schools. District officials will also look at ways to stretch its $8 million, using alternatives to air conditioning such as ceiling fans and better insulation.

An in-house pilot study could begin as early as the first quarter of next year. That's good news — the sooner the better. Because while the DOE is studying the problem, students and their teachers are studying in stifling 80-plus-degree heat. Every school day that goes by with these conditions unchanged is another school day lost.

And that's more than suboptimal. It's unacceptable.