Since 2007, electricians have been required to install fire protection guards over downlights. But many unsafe downlights installed before 2007 remain unfixed, says Mr Duggan.

"Anyone with downlights installed prior to two years ago and with blow-in insulation would have this situation. There would be thousands and thousands of downlights in Victoria without fire barriers." Mr Duggan recently attended a job at the home of "lucky" Cranbourne resident Joanne, who had detected a burning smell from her ceiling.

Insulation was covering many of her eight-year-old home's 26 downlights, which were 'protected' by cardboard surrounds.

One of the surrounds had collapsed on a downlight and was close to igniting. It could have set alight surrounding insulation and caused a roof fire, says Mr Duggan. "It was lucky the cardboard didn't touch the globe."

Joanne said she hadn't been aware of the potential danger of downlights.

"We're fire-conscious. It cost me $1300 for fire protectors and smoke detectors, but it's your life you're talking about."

Dave Baker, CFA Western Port region community safety manager, said downlights were a continuing contributor to home fires.

"It's important that downlights are installed by a registered electrician according to the relevant codes. There has to be enough space between the downlight, which heats up enormously, and what's around the light."