How to Cool Down Your Swimming Pool Water

Written by Michael Dean
December 21, 2023

cooling down swimming pool water

Like everything else exposed to the air, swimming pools can change temperature over time, regardless of how well-insulated the sides of the pool are. For most people, the cold air during winter is a big threat from changing temperatures, but there are times when a pool gets too warm and needs to cool off.

If you’re in this relatively unusual situation, don’t worry. Here’s what your water temperature should be and how to cool your pool down quickly.

Main Takeaways

  • Most swimming pools are between 78 and 82 degrees, with athletes preferring cooler pools and those with physical ailments preferring warmer water.
  • To cool down your pool, use fountains or waterfalls, adjust the landscaping, add ice, do a partial drain and refill, use solar cooling with your solar pool heater, or use an active cooling system like a reversible heat pump or evaporative cooler.
  • My recommendations for cooling down your pool are an evaporative cooler or solar cooling if you already have a solar heater and live in a sunny climate.

Common Pool Temperatures For Residential Pools

As noted by the Department of Energy, the average pool usually ranges from 78 to 82 degrees. Most competitive swimmers use the low end of that, while some people with physical ailments prefer warmer water.

How To Cool Down Your Pool

Every degree matters for swimming pools. After all, heating ten thousand gallons of water, even one degree, takes quite a lot of energy, and the energy costs tend to go up significantly for each degree. While making the temperature go up is as easy as turning a pool heater on (also, check out my research for the best pool heater), cooling it down is a little more complicated. Here are the best strategies for cooling pools of any size.

Trick #1: Fountains or Waterfalls

If you have the money, installing a fountain or waterfall system is a great way to lower the temperature of your pool. Running this system at night moves more water through the cold air, which noticeably reduces the temperature of the water. Running it during the day can help, but that isn’t quite as effective for cooling the pool down quickly.

Trick# 2: Adjust The Landscaping

The easiest and most natural way to cool down a pool is to have air flow across it. This is fundamentally the same strategy as our first trick, but we’re approaching it from a different angle. In some locations, trees or plants can block the normal airflow of the area and limit how much air moves over the pool.

Adjusting your landscaping to ensure the wind goes over your pool allows you to quickly and efficiently cool it down.

Trick #3: Add Ice

This only works if you have access to a whole lot of ice at a low price point. As humorous as it may look, adding ice in bulk is one of the fastest ways to cool down a large swimming pool. This is most effective if you need to chill things in a hurry.

Trick #4: Partial Drain And Refill

Partially draining and refilling the pool is the most accessible method of cooling it down. Most municipal water supplies are relatively cold to start with, so dumping out about 10% of your pool and adding new, cold water will quickly cool it off.

The downside to this strategy is that you’ll also need to rebalance your pool chemistry, and it’s a little expensive if you have a large pool.

Trick #5: Solar Cooling

Did you know that most solar heating systems for pools can also cool them? If the air temperature is colder than pool water, most solar systems can use nocturnal cooling to radiate heat into the sky and away from your pool. This is very effective, but the necessity of having a solar heating system for your pool makes it a little harder to accomplish.

Trick #6: Active Cooling

Active cooling systems are arguably the most popular way to cool down residential swimming pools. These come in two common forms.

The first (and most popular) version is a reversible heat pump. These systems can heat and cool pool water, making them extremely useful in areas with significant temperature fluctuations. Some reversible heat pumps are automatic and can switch modes as needed. While useful, these tend to take a lot of electricity to run, so you can expect to see a higher energy bill.

Evaporative coolers are significantly less expensive than reversible heat pumps and are ideal for use in areas where cooling is necessary, but heating isn’t. The simple reason for this is that they don’t heat water in the first place. When appropriately installed, evaporative coolers can usually reduce the temperature of a pool by at least 5 degrees, which is about all that most people need.

Which Option Is Best for Me?

Personally, I recommend getting an evaporative cooler if you need cooling for extended periods. It’s affordable, easy to install, and highly effective. Ice is exceptionally useful for fast cooling, but it’s also a one-time strategy for most people, and your pool will likely end up heating back up in just a short amount of time. Solar cooling is also viable, especially in warm regions with a lot of sunlight, so it’s worth considering as an alternative. Before you buy any new product, though – assess your backyard environment and make sure you’re providing enough shade for your pool or (conversely) enough wind exposure to allow Mother Nature to help out, especially if you’re in a hot region.

For more temperature-related articles, check out my guide on the perfect pool temperature.

Get My Free Pool Care Checklist

Download my free, printable pool maintenance checklist to help you accomplish regular pool care tasks for any type of swimming pool.

Something went wrong. Please check your entries and try again.
Scroll to Top