Larchwood Primary School began the works last year to create a more modern and comfortable learning environment.
The project, funded through the Government Condition Improvement Fund, included upgrades to heating, lighting, and water systems.
Steve Bowsher, headteacher at Larchwood, said: “The new ceiling heaters are highly efficient and will save us a lot of money long-term; they heat a classroom in minutes.
“Each classroom also now has sensors, so lights will automatically switch off when a room is not in use, so they are also more energy efficient.
“With school budgets being challenging at the moment, these changes make a big difference.”
MORE NEWS: Cafes at Essex parks could shut under new proposals
The school now also benefits from an upgraded water and heating distribution system.
Old underground pipes have been replaced with more accessible external ones, and Victorian-era radiators have been swapped for modern ceiling heaters.
Ceilings and 46 fire doors have also been replaced.
Bew parquet flooring has been installed throughout the hall, corridors, and classrooms.
During the October half-term, a school spokesperson said its toilets will be refurbished and floors replaced.