The shift to a standard calendar that has everyone returning to classrooms at the end of July has put fresh attention on the sometimes-intolerable conditions in our schools.

The facts aren't particularly new: Our public schools often are so stuffy and hot that learning suffers.

Part of the explanation is that our public school infrastructure is old. What once might have been a breezy open-air structure at the edge of a canefield now is surrounded by asphalt and housing.

While there has been a substantial increase in the amount of money allocated for air conditioning and other improvements, it remains far from adequate.

According to education writer Beverly Creamer, the Legislature has boosted its support for retrofitting our hottest schools from around $2 million to $10 million.

But with a single retrofitting project costing from $3 million to $5 million, this is still far short of what is needed.

School officials are doing their part by creating a priority list for central air conditioning based on the most sensible of criteria: Highest average temperatures.

Lawmakers should honor this list and avoid temptation to put money into projects based on political clout.

There also is room here for private companies to step up and help. Such public-private partnerships in similar cases have been successful statewide. And investing in the education of our children — our future workforce, our future leaders— is sure to pay off in the long run.

It's also time for a fresh approach in the way we measure the costs and benefits of air conditioning or otherwise revamp our schools to make them more comfortable.

Businesses, government offices, shopping malls and other facilities are air conditioned not so much out of consideration for the occupants but rather out of a concern for productivity and efficiency. A comfortable environment leads to greater work efficiency or, in the case of schools, greater and more productive learning.

How does one account for the cash value of lost learning opportunities due to difficult or unbearable conditions?

Measured this way, it's a good bet that lawmakers and school officials would conclude that the payoff more than justifies even greater focus on improving the physical condition of our schools.