Havelock North Primary School is installing solar panels throughout the school.
Isaac's Plumbing and Electrical donated $25,000 for the installation of a 20kw solar panel system.
Havelock Primary Board of Trustees chairman Mike Lewis said the benefits for the school would be financial, educational and environmental.
"With these 30+ degree temperatures in Hawke's Bay we can have the air conditioning on and it's essentially free. We are also collecting power and feeding back to the grid when we're not using it; we're storing up power to use later," Lewis said.
"When teachers flick lights on in the classroom they will be making the most of those new panels. It's a saving from the start and, throughout their 25-year lifespan, those savings just keep adding up," Isaac's director Gavin Streeter said.
This is stage one of the school's switch to solar energy.
When funds are raised, stage two will enable the installation of another 60 solar panels before the end of the year.
One panel costs $225 but will save the school $2500 over 25 years.
"As part of the system, we will have a monitoring and education tool that teaches children about what's happening with power and how they are using it," Lewis said.
Lewis said the school would also have a monitoring and education tool to teach children about power and the effects switching off lights can have.
"In schools, the cost of power is dead money. Now we have more to spend on educational resources," Havelock North Primary School principal Nick Reed said.
"It's also good for kids to learn how solar power can reduce costs in a climate where a power is often wasted. Sustainable energy has been on our agenda for years, but the generosity of Gavin and his family means we can have it up front, without having to accumulate funds over time," Reed said.