---
title = "Bubble direction on a solar cover doesn't matter much"
type = "report"
source_topic = "solar cover bubble direction"
---

It doesn't really matter which way the bubbles face.

The conventional wisdom says bubbles down for insulation, bubbles up for keeping debris off the water. In practice, the difference is small enough that you won't notice.

Bubbles down traps a thin layer of air against the water, which does slightly improve heat retention. Bubbles up means the dimples collect leaves and dirt, but also might reflect a bit more sunlight back into the pool. Most covers are designed with the assumption you'll put the bubbles down.

If you're installing a new cover, go bubbles down. If you already have it flipped the other way, don't bother redoing it. The cover works either direction.

Don't overthink it.