Some 24,000 traditional yellow lamps around the city are being changed so they omit a white light, reducing the wattage of each from 70 to 50.
Cardiff council said the new StreetWise lamps would be dimmed from midnight until 6am.
The Energy Saving Trust said new technology meant streets could remain well-lit while saving resources.
The council said the new lights would be fitted to existing lamps across the city over the next year, with the rollout already started in north Cardiff.
A council spokesman said: "It's a whiter light but it produces an energy saving of 33%."
He said the changes follow an 18-month trial in Radyr during which the authority did not receive any complaints.
GE Lighting, which makes StreetWise lamps, said they are a shift away from the traditional "dizzy, yellow" light to a more "clear, crisp white light".
The company said the light improves public safety and improves efficiency.
Duncan McCombie, director at the Energy Saving Trust, said Cardiff council was taking "an innovative approach" to street lighting.
"Newer technology allows our street to continue to be well lit and safe while reducing energy used, helping the council direct money to essential services while doing their bit for the environment," he added.
It comes about three years after some councils in Wales started turning off residential street lamps in a bid to save money.
Street lights across Cardiff are changing colour as part of a drive to save energy and money.