Watford Grammar School for Boys has secured £1million to redevelop its sports pavilion at Coningsby Drive.
The school won £500k funding from Sport England and £500k from the Academies Capital Maintenance Fund to replace the old single storey pavilion built in 1968 with a state-of-the-art two storey building.
The new facility is set to serve the school and its sports partners as well as community sports clubs in the area.
It will comprise several changing rooms on the ground floor as well as a function room with a viewing gallery on the second floor.
The new building also includes several environmental features such as heat pumps, solar panels and rain water harvesting.
Mark Allchorn, deputy head, said "By ensuring the facility is environmental sustainable we can save significant money on running costs. We are expecting energy bills for the facility to reduce by at least 10-20%."
Work on the pavilion is likely to end in November 2014, and will be officially opened in Spring 2015.
Headmaster Martin Post said: "This investment reflects the high calibre of sport we deliver at the School as well as the excellent sports offering of our sports community partners.
"In the long term we hope the new pavilion will become hub for local sports excellence offering clear sporting pathways to young people to continue to play and develop sports skills beyond school."
Sport England property director, Charles Johnston, said: "We know people have a better experience of sport when they have good facilities in which to play.
"This investment will ensure the people of Watford will be able to develop a sporting habit for life in a first-class, environmentally sustainable sports facility"