Nobody wants to swim in an ice-cold pool. Since black clothes, cars, and outdoor furniture attract heat, it’s understandable that you might think black plastic could heat your swimming pool. However, using the wrong kind of plastic could clog the plumbing, encourage algae growth, and fall apart in the water.
Black plastic will heat your pool if it’s a solar cover or solar ring. However, you shouldn’t use any type of plastic that isn’t designed for a swimming pool. Garbage bags, plastic sheets, and tarps will fall apart and get caught in the baskets and filters. Additional heat can contribute to algae.
In this post, I’ll explain why black plastic works so well to heat your swimming pool, whether or not you should get a black solar cover, and why you should avoid using garbage bags to heat your swimming pool.
Does Black Plastic Raise Your Pool’s Temperature Quicker?
Black plastic raises your pool’s temperature quicker because black absorbs more heat than blue or gray. However, clear solar covers heat pools faster than any other option because they retain the heat without keeping any of it in the cover’s plastic. Make sure the bubbles are in the correct orientation for maximum heating.
Your solar cover’s bubbles should point down because the direction allows the bubbles to absorb and distribute more heat. If the bubbles face up, the bottom of the cover will corrode, regardless of the color. Darker solar covers tend to heat more, but slight transparency is better than a solid black color.
You could also use a black hose to heat the pool under the solar cover. The dark color sends more heat into the pool, then it can’t escape thanks to the dark pool blanket. The most important thing to remember is that the black plastic needs to be of the right thickness. Pool covers come in various thicknesses, but the best options are 12mil and 14mil.
Will Black Garbage Bags Heat Your Pool?
Black garbage bags will heat your pool, but they can also shred the plumbing. The chlorine and sunlight corrode the garbage bags, which breaks them apart. The tiny plastic bits get into the pump’s basket. Small debris can tangle in the impeller and overheat the motor. Always choose pool-rated covers instead of garbage bags.
Here’s what you should know about using black garbage bags to heat a pool:
- If you’re determined to use black trash bags to warm the water, make sure they’re as thick as possible. Thin garbage bags are much less durable, which means they’re more likely to fall apart. You’ll have to dive into the pool to retrieve the countless bits of plastic to prevent unwanted clogs.
- Spray the garbage bags with water every couple of days to wash the chlorine off of them. Chlorine bakes onto the plastic trash bags. They need to be washed regularly to stop the chlorine from deteriorating the plastic. This process is also required for pool-rated solar covers and solar rings.
- Throw away the bags if they get porous or worn down. It’s not worth patching them since they’re ultra-cheap and can break apart. Your trash bags shouldn’t sink, rip apart, or pull into the skimmer. Check the basket daily to ensure the plastic isn’t suctioned into the skimmer’s inlet.
- Wrap the garbage bags around pool noodles to create DIY solar rings. You can wrap extra-large black trash bags around pool noodles folded into a circle. Tape them with waterproof tape to prevent the plastic from falling off the pool noodles. Cover as much of the water as possible to promote optimal heating.
- Add a liquid solar blanket to increase the pool’s heat and water retention. Liquid solar covers retain more heat and water, so you can combine them with trash bags or solar covers. Natural Chemistry’s Cover-Free holds up to 70% of heat and 85% of water evaporation. It’s an excellent natural chemical to improve the black bags’ performance.
Pro Suggestion: Opt for solar covers and solar rings before choosing black garbage bags. I’ve had to repair plenty of pool pumps and filtration systems from deteriorated plastic. They can be used for a few days, but they’re not worth the hassle in the long run. Learn more about choosing the correct cover color below.
Does a Black Pool Cover Help Heat the Pool?
A black pool cover helps heat the pool because it absorbs a lot of heat and traps it in the water. You could choose a transparent black cover for the best of both worlds.
The black color attracts the heat, whereas the clear transparency lets more sunlight pass into the water. Heating your pool can cause algae blooms if there’s not enough chlorine.
Solar covers work by attracting heat and trapping it in the water. The thick plastic cover prevents the heat from leaving the water if the cover is thick enough. Every millimeter of thickness makes a huge difference.
Keep these two factors in mind when getting a pool cover:
- The solar blanket’s cover matters. Dark blue is the best color, followed by clear black and clear gray colors. You could also choose a light blue shade if you don’t want too much heat retention. All of the colors retain the same amount of heat.
- The thickness is often more important than the color. Solar covers should be between 10mil to 14mil, with 14mil being the best choice on the market. It’s thick enough to retain heat and water but thin enough to prevent it from sinking. You can notice up to 15% heat retention by switching from a 10mil cover to a 14mil cover.
The Blue Wave 14mil Solar Cover is a clear solar cover that can prevent up to 95% of evaporation. It can also raise your pool’s temperature by 15 degrees Fahrenheit.
You’ll also enjoy the six-year warranty and the fact that it’s more effective than black, blue, and gray solar covers. Make sure you use algaecides and chlorine to combat the algae from the excessive heat.
Jonah has worked for several years in the swimming pool industry installing and repairing equipment, treating pools with chemicals, and fixing damaged liners. He also has plumbing and electrical experience with air conditioning, ceiling fans, boilers, and more. When he’s not writing for Temperature Master, he’s usually writing for his own websites, LawnCareLessons.com and DIYByHand.com.