The Drain Pan Problem: Where Mould Starts In Every Split System

Ever wondered what it looks like inside the drain pan of an air conditioner? Here you go — this is where the mould factory lives.

Every split system has a drain pan underneath the cooling coil. When the unit runs, condensation drips off the coil into this pan. In theory, it all drains outside. In reality? A sludge of moisture, dust, and organic matter sits in the bottom — and that's exactly where black mould takes hold.

Why It Happens

The coil produces condensation. That water drips into the drain pan. But it doesn't all drain out — there's always a little bit of sludge sitting in the bottom. Add Central Coast humidity and you've got the perfect breeding ground for mould spores.

This is what causes that musty, damp smell when you turn your air conditioner on. You're not imagining it — that's mould you're smelling. And you're breathing it in.

Can I Clean It Myself?

You can wipe the exterior and clean the filters. But the drain pan is buried deep inside the unit — you need to strip the covers, remove the electrical housing, and get right in there. A surface spray won't reach the sludge at the bottom.

This is why a professional deep clean removes 99% of the internal build-up. We strip the unit, chemically clean the coil, flush the drain pan, and sanitise everything.