A solar cover’s heating power comes from the air bubbles lined along the lower surface, which collect the heat from the sun’s UV rays and transmits it into the swimming pool. While many consumers may believe that all solar cover bubbles are created equal, bubble shape can have a big impact on how much heat is transferred to your pool water, as well as how easy the solar cover can be to maintain.
Round solar cover bubbles and diamond-shaped bubbles are two of the most popular designs, each with their own pros and cons. Which is right for you?
Round air bubbles are the most commonly used style on most pool solar covers. All air bubbles do an effective job at transmitting heat from the bubble’s interior air pocket to the water touching the exterior surface of the air bubble, raising your pool water’s temperature.
The disadvantage of the round bubble, when compared to a diamond shaped bubble, is that round bubbles simply can’t be in all places at once. Patterning up several circles on the solar cover’s surface creates little gaps between each air bubble. Without corners, the bubbles create even larger gaps between rows. The water that fills these gaps are not touching an air bubble, and therefore are not directly accepting heat from the solar cover.
While this series of gaps may sound unfavorable, they are not without their benefits. The gaps allow for the pool water that has been sitting between the air bubbles to easily roll off of the cover as it is being picked up off of the pool or rolled up onto a solar cover reel. When rolling up your solar cover, the water easily slides off and all that is being rolled up is the cover, with no additional water weight.
Diamond shaped solar cover bubbles work in exactly the same manner as round solar cover bubbles, however, their shape provides one distinct advantage of allowing bubbles to sit closer to one another. This design greatly reduces the gaps between the air bubbles and creates a larger heating surface area, meaning more water is touching the surface of an air bubble at a time. This allows heat to be transferred faster and easier than a cover with less surface area. With all other conditions being equal, a diamond bubble solar cover can transfer more heat to your swimming pool than a round bubble cover over the same amount of time.
This advantage does not come without some trade-offs. Putting more air bubbles on the cover requires the use of more material, which raises the cost of these solar covers a bit.
The largest disadvantage of diamond bubble covers lies in how these bubbles react when working in conjunction with a solar cover reel. Since the diamond bubbles have less space between one another, it becomes harder for water that is between the bubbles to escape the gaps before the cover is rolled up onto a reel. Rolling up a diamond bubble cover onto a reel often traps a lot of water in solar cover, adding significant weight to the load the reeled tubing has to bear. A diamond bubble solar cover can be rolled up by hand, but the cover will be heavy and will need to be dried off. Exposing the solar cover material to pool chemicals for a prolonged storage period (in addition to already being exposed to them while sitting on your pool) will cause the solar cover material to deteriorate faster.
Deciding between round and diamond solar cover bubbles depends largely on your particular situation and preferences. If you prefer the convenience of using a solar reel and don’t mind losing a bit of heating efficiency, then round solar cover bubbles are for you. If you find the added pool heat to be worth a little additional effort in handling and maintenance, then the diamond air bubbles would be a better choice.
While diamond bubble solar covers may cost slightly more than round bubble covers, each additional degree collected from the sun’s rays means fewer degrees you have to add to your pool by other paid methods, such as an electric or gas powered pool heater.
Diamond shaped bubbles are traditionally only found on clear solar covers, as their additional heating aids the deeper heat penetration that clear covers provide. However, if you’ve found that a different colored solar cover works better for your pool. Then diamond air bubbles may not even be an option. You can learn more about the pros and cons of different solar cover colors here.
Regardless of which bubble style you choose, having a solar cover is better than no cover at all. And it should be noted that bubble shape does not affect the solar cover’s insulation properties, so your cover’s effectiveness at retaining heat and preventing water evaporation won’t cut corners, even if your solar cover bubbles do.