Andover schoolchildren will dress in layers this fall — and not just for fashion. Principals districtwide have been asked not to turn the heat on in schools until Oct. 15, as a cost-saving measure.

After conferring with the Plant and Facilities Department, Dave Keniston, who was hired as the school district business manager this summer, suggested the Oct. 15 date to establish a districtwide, uniform guideline for heat usage.

"It's part of a larger proposition we have to save energy. Every public school district is going to be watching those energy dollars," Keniston said. "We're just trying to discipline ourselves, so I set a target date for turning on the heat in the month of October.

"These bigger buildings with boiler systems can use up to 40 gallons per hour. At the rate we're paying for oil, that can be expensive," he said. "We're looking at it as a sound business practice."

The Oct. 15 rule is not set in stone, he said, and individual principals can turn the heat on as needed.

"After the 15th, we could get into a great Indian summer," he said. "But if we had a Northeast storm and it was really cold, obviously we're going to make people comfortable. We're in the business of keeping people healthy and safe."

Keniston first introduced the idea at a principals' meeting last week, and everyone came to a "pretty good agreement" not to turn heat on until the Oct. 15 date, he said.

Moira O'Brien, principal at Shawsheen School for kindergarten through grade two, said Oct. 15 does not seem too late for the heat to come on. Ultimately, she said she'll do what's best for the students, especially because Shawsheen has younger students, including preschoolers.

"If the weather is unusually cold, we have and will turn the heat on (before Oct. 15)," she said in an e-mail.

Andover public schools do have three days off before then, when heat won't be a concern — Sept. 30 for Rosh Hashana, Oct. 9 for Yom Kippur, and Oct. 13 for Columbus Day.

Setting a districtwide guideline for heat and/or air conditioning usage is common in public schools, Keniston said. In prior years, Andover had no set date for turning on heat, he said, and the decision was left up to the individual schools.

Keniston also suggested principals use the "building flywheel effect" during spring and fall "shoulder seasons," he said.

In the flywheel effect, a short blast of heat is used in the morning to make the building comfortable, and then the thermostat is switched off. The lighting and people keep the building warm for the rest of the school day, he said.

His biggest concern is when heat usage causes schools to become overheated, said Keniston.

"In the shoulder seasons of spring and fall, it's very easy to overheat (buildings). The last thing we want to do is drive by and see windows open," said Keniston.

Keniston was hired by Superintendent Claudia Bach in July. He previously worked in the Marblehead public schools.

Coming to the district as an outsider, Keniston noted that Andover's schools are "in great shape."

"The care they take and the concern they have over energy (in Andover) is amazing," he said.