Which way should solar pool cover bubbles face? The answer is. The bubbles must face Down.
Why is this? Your pool cover is designed to absorb heat from the sun and then transfer this heat into the pool water. By facing the pool cover Bubbles Downwards onto the water, the sun’s heat is trapped in the blanket, and the air inside the bubbles is heated up and then this heat is transferred, via the heated air in the bubbles, to the pool water, therefore, trapping the heat in the water and preventing the warmth from escaping back out into the air.
Due to pool water evaporation being a major cause of heat loss the solar pool cover reduces this evaporation and therefore the pool’s water retains its heat.
If you accidentally place your pool solar cover on the pool with the bubbles facing up, the bubbles can be damaged. How do they get damaged? They can overheat, distort, the material can get thinner and disintegrate. The UV rays from sunlight also damage the bubbles.