Is it safe to put insulation over downlights?

Not over the top of them, no, and a careful installer never does. A recessed downlight runs hot, and old-style halogens especially throw off a lot of heat into the roof cavity. Pack insulation hard against one with no clearance and you've created a fire risk that didn't need to exist. That's exactly what caused so much grief in the pink-batts days, when insulation got pulled over hot fittings by crews who didn't know better. The safe way is to keep the clearance the Australian Standard requires around every downlight, exhaust fan and flue so the fitting can shed its heat, and never bury it. With pumped cellulose we shroud those fittings so the blanket stays back off them, and our installers photograph those exact spots so it's on record the clearance was kept. If you're worried about your existing lights, the better long-term fix is to have a licensed electrician swap them to sealed LED fittings rated to be covered, but that's a sparky's job, never an insulator's.

There's a required clearance set by the Australian Standard for insulation installation and by the light fitting's own instructions, and a careful installer keeps to it, but I'm not going to print one flat number on a web page as if it covered every fitting, because it doesn't. The clearance depends on the type of downlight: an old uncovered halogen transformer needs a generous gap and a shroud so nothing touches it, while a modern sealed LED stamped "IC-4" (insulation-contact rated, sealed so it can be covered and abutted) is built to be covered safely. That's why we don't guess; we identify what's actually in your roof, keep the clearance the standard and the fitting call for, and photograph it. If your downlights are the old hot type, the right answer isn't to cram insulation around them; it's to have an electrician change them to an IC-4-rated LED. We'd suggest that even if you're not asking us to cover them, because an old halogen or 240 V light is a heat source and can't be covered, so it forces a bare gap around every fitting that pulls down your ceiling's real R-value. Once they're IC-4 LEDs we can insulate fully.

It can, when it's done wrong, and the pink-batts scheme is the proof. Insulation packed onto hot fittings was blamed for dozens of house fires during that program, which became the subject of a Royal Commission. The fitting can't shed its heat, the heat builds up against combustible material, and you get a fire that started in the ceiling where nobody could see it. The fix is not complicated and it's the installer's job: keep the required clearance around every downlight, fan and flue, shroud the hot ones, and never let anyone disturb your wiring as a shortcut. That's a licensed electrician's work. Borate-treated cellulose is itself made to resist carrying a flame, which is a help, but no insulation makes a bad install safe. The safety comes from keeping it clear of the hot fittings in the first place.

It can put you at risk. The insulation sitting in your roof isn't the danger. A non-compliant install is. If insulation is packed against a hot fitting with no clearance, a fire ever starts there, and an assessor finds the work wasn't done to code, your insurer can argue the loss was preventable. Most of this work is in a roof you'll never climb up to inspect, so if you can't see it, you can't prove it was done right. That's the real value of photographing the clearances around every downlight, fan and flue: if an insurer or an electrician ever asks whether the insulation was kept clear of the hot fittings, you've got a dated set of photos showing it was. A cheap crew that leaves no proof leaves you with nothing to show but a hole in the ceiling.