Areas tested included durability, with three samples of each lamp left on for 5,000 hours and switched on and off 30,000 times. With the best performing bulbs, all three samples survived testing, while the worst failed at just 6,000 switches.
Other test areas included brightness across a 100-hour period and speed to light.
Of the 15 products picked out as ‘best buys’ by Which?, nine were from Osram, four from Sylvania, one from GE and one from Philips.
Osram’s Duluxstar Mini Twist 11W came top of the list as the ideal replacement for the traditional 60W lamp. Although Sylvania’s ToLEDo GLS A60 performed better, its typical price is almost six times more than the Osram bulb.
The Which? test report said: ‘The Mini Twist from Osram does many things excellently. Its performance is good as it gets for a CFL light bulb.’
The GE Electronic 12W also performed strongly, particularly for light output, efficiency and durability. The Osram Duluxstar 21W and Dulux Superstar 30W were recommended as replacements for traditional 100W lamps.
Osram’s LED lamps scored well in the durability tests and only took three seconds to reach full brightness. The Osram Parathom Pro Classic A60 and the Osram Parathom Classic A40 were also picked out as best buys.