BOISE, Idaho (AP) — Idaho officials concede the five-year, $2.1 million annual contract the state Department of Education signed Wednesday with a Tennessee company to install Wi-Fi service in public high schools may cost more per-school than deals districts negotiate on their own, but insist that simple numbers don't tell the whole story.

For instance, the Coeur d'Alene School District was planning to spend $18,000 annually from local tax collections to hire a company to host three high schools' wireless service, or about $5,666 per school, a spokeswoman said Thursday.

Under Idaho's pact with Nashville-based Education Networks of America, by comparison, the per-school cost could run nearly four times that amount, or nearly $23,000, on average, based on 93 high schools state Superintendent of Public Instruction Tom Luna said have so far signed up.

Luna's office said the list of schools that will participate will grow between now and Aug. 1, the deadline to take part during the 2013-14 school year. And future years will likely bring more converts, he said, pushing per-school costs even lower. If all 340 high schools in Idaho were to participate in the ENA contract, the average per-school charge would drop to $6,200.

"The contractor had to take on all the risk, assuming 340 high schools did sign up in the first year, and would have to pay for it," said Melissa Mcgrath, Luna's spokeswoman. "That's the way the contract is structured."

And Education Department officials also contend building a system statewide poses challenges, given ENA must erect and service networks not just in modern, urban schools where Wi-Fi might be cheaper to install, but also in aging buildings located in the state's rural hinterlands where service could be costlier.

"Some school facilities are older and may require more time, energy and equipment than newer school buildings that have more up-to-date infrastructure in place," said Joyce Popp, the agency's chief information officer in Boise.

By Thursday, the Coeur d'Alene School District was already considering joining the statewide contract — despite already getting bids from competing vendors for its own Wi-Fi proposal. The promise of having the state pick up the tab for would have been a five-year, $85,000 drain on local funds was too good not to consider.

"We were in the process of bidding it out," said spokeswoman Laura Rumpler. "Now, we're in a slight holding pattern."

At School District 91 in Idaho Falls, which already has different levels of wireless service at its four high schools, chief technology officer Camille Wood is also reviewing ENA's proposal.

But Wood said determining whether the statewide contract's price tag is appropriate will take further study. She wants to know, among other things, if ENA is committed to moving quickly to update networks when next-generation wireless technology emerges.

"I think that's difficult study," Wood said. "We don't know what it all entails."

ENA officials in Idaho pledged to deploy equipment that meets the industry standard.

"As new standards are made, we will upgrade to serve those new standards," said Garry Lough, customer services director for ENA in Boise.

In Meridian, Idaho's largest school district, its high schools plan to join the ENA contract, said spokesman Eric Exline. While Meridian's high schools already have Wi-Fi systems, the networks aren't as robust as those foreseen under the ENA contract.

"What our signing up in this ENA contract would mean, those companies would come in and beef up and add to, and replace, to create a system where you would have... every student be able to come in and hook up and have Internet access," Exline said.

West of Boise in Canyon County, the Nampa School District just spent $12,000 to build separate Wi-Fi networks in its three traditional high schools, but like Meridian's, these systems also can't accommodate all 4,000 students simultaneously. It's considering opting into the state contract.

Chief technology officer Bill Beverage said Thursday it wouldn't be fair, based on price alone, to compare locally-built Wi-Fi networks with the statewide system, which will come with the advantage of a system manager tasked with maintaining equipment and replacing components that break or become antiquated.

"I welcome what the state is doing," Beverage said. "I'm not going to assess whether it's economical. I don't know how many, or what kind of devices they're going to be using."