NASHUA — A Merrimack company will be exploring the costs of potentially installing solar panels at several city schools.

This week, the Board of Education asked Energy Efficient Investments to move forward with an investment-grade energy audit of the schools, and determine cost estimates to install solar at four local schools.

Mike Davey of EEI said solar panels are feasible at Dr. Crisp Elementary School and Fairgrounds Middle School, since those roofs are relatively new. He did not recommend placing solar panels on the roofs at either Nashua High School South or Nashua High School North, since that infrastructure is older.

However, board member Dotty Oden requested that EEI also study the costs of placing ground-mounted solar panels at the two high schools as an alternative.

“The goal is to develop a project that is tax-neutral,” Davey told school officials.

During a preliminary review, EEI recommended more than $7 million in work at the two high schools — $3.6 million at North and $3.8 million at South — to improve energy efficiency and ultimately reduce energy costs.

EEI, an energy contracting company, was hired by the school district about seven months ago to review the city’s schools and study potential ways to become more energy efficient.

Nashua High School North and Nashua High School South are the district’s two largest energy users. EEI said it has found numerous improvements that could be implemented to guarantee annual energy savings, including LED lighting and infrastructure upgrades on hot water heaters and transformer replacements and more.

“A lot of the savings come from LED lighting,” said Davey.

If the recommended $7 million in improvements are made to the high schools, he predicts about $220,000 in annual energy savings at each of the facilities. The district would also be eligible for $400,000 in grants and rebates toward that work, added Davey.

The payback period would be about 14 years, he explained. While there are different bond or lease financing options available, Davey proposed that the amount of annual energy savings would be equal to the annual bond payment.

He stressed that the financing numbers and cost savings are still preliminary.