Pool Too Hot? How to Choose the Right Chiller for Texas Summers
Should I Buy a Chiller for My Pool?
It depends. When summer hits North Texas, the idea of cooling your pool sounds more like a necessity than a luxury. With outdoor temperatures frequently climbing into the 90s and beyond, many homeowners turn to air-cooled pool chillers as a solution. Why? Because they don’t understand the science behind them and their pool cleaner sold them on the great idea! So before you invest in a unit like the Hayward HeatPro or the Jandy JRT3000, there are critical performance factors to understand that often go overlooked.
The Science Behind Air-Cooled Chillers
Air-cooled chillers work by pulling heat out of your pool water and releasing it into the surrounding air. They function similarly to an air conditioner, using refrigerant, compressors, and fans to extract heat from the water and discharge it through a condenser coil. But here’s the catch: these systems are only effective when the air temperature is cooler than the pool water.
That’s right, read that again. When is the last time in Texas you went outside during the summer and said, “I wish my pool was this temperature.” Probably Never.
In other words, air-cooled chillers need cooler air to "absorb" the heat being pulled from your pool. If the outside air is warmer than your pool, there’s nowhere for that heat to go. In those conditions, the chiller not only struggles it becomes ineffective.
The Texas Summer Challenge
Let’s look at a real-world scenario using North Texas climate data for June:
Average High Temp: 92°F
Average Low Temp: 71°F
Average Daylight Hours: 14.3
Average Darkness Hours: 9.7
In fact, on average about 13-17 hours of the day in June in Texas are spent above 85°F. Meaning only 8-11 hours are even possible to lower the water to the ideal temperature. A common pool temperature goal in summer is around 78°F to 80°F. But with water exposed to 13+ hours of sun and high radiant heat, it's easy for a pool to reach 88°F or hotter. Let’s say you have a 20k Gallon Pool and the current water temperature is 88°F. Running a chiller like the Hayward HeatPro (Optimal Flow Rate is 45GPM) or the Jandy JRT3000 (Optimal Flow Rate is 57 GPM) might allow you to lower the temperature by 2 to 3 degrees overnight under perfect conditions. But as soon as the sun hits the water again in the morning, your pool rapidly reheats.
Why Efficiency Drops Off
Even during nighttime, ambient air temperatures in the low 70s don’t allow for highly efficient heat removal. Chillers operate best when there is at least a 10-15 degree difference between the water temperature and the air temperature. As the water temp approaches the ambient air temp, chiller performance tapers significantly. In midday heat, when the air is hotter than the water, most air-cooled units become completely ineffective.
This is known as non-linear cooling, which means the temperature doesn’t drop by the same amount each hour.
1. ΔT (Delta T) Shrinks Over Time: The greater the temperature difference between pool water and the air/chiller coil, the faster the heat transfer. As the pool temp gets closer to the target temp or ambient temp, the delta shrinks → less BTU/hr is pulled → slower cooling.
2. BTU/hr Performance Drops: Manufacturers rate chillers at a certain ambient air temp, humidity, and water temp. When your pool is hot, the chiller can pull more BTUs/hour. As it cools, the BTU output decreases, because: The compressor becomes less efficient.
Less heat is available to extract.
So even though your chiller might be rated for 130,000 BTU/hr, that might only apply when:
Pool = 90°F Ambient = 75°F Humidity = optimal
As the pool cools to 78°F, the effective BTU/hr drops.
Example Scenario:
The image above shows a pool chiller performance scenario for a 512 sq ft pool with 20,000 gallons. It calculates cooling time to drop water temperature by 5°F in August, using a 130,000 BTU chiller at 57 GPM. It compares cooling efficiency at different conditions (fastest, 60%, and 75% efficiency), estimating required BTUs and total chill time ranging from 8.55 to 14.63 hours depending on efficiency and weather.
It presents estimated chill times under different efficiency scenarios:
Fastest Possible Chill Time: 14.63 hours
Estimated Time @ 60% Efficiency: 10.69 hours
Estimated Time @ 75% Efficiency: 8.55 hours
The chart also includes delta temperature drops per pass (inefficient and efficient scenarios) and is designed to help our designers quickly assess how long it will take to chill the pool based on current flow and efficiency conditions.
Chiller Sizing & Cooling Time Estimate for Residential Pool in Texas (BTU/hr vs. Flow Rate Table)
This chart outlines a real-world example of how long it takes to chill a 20,000-gallon residential swimming pool in North Texas summer conditions using a 130,000 BTU/hr water-cooled chiller. It factors in solar heat gain, desired water temperature drop, and flow rate efficiency, making it ideal foranyone looking to properly size and estimate chiller performance.
It shows how long it takes a chiller to reduce pool water temperature, based on flow rate (GPM) and chiller efficiency.
Gray-shaded cells show when flow rate is the limiting factor. Increasing efficiency at these flow rates won’t chill the water faster because the water simply isn’t moving through the system fast enough, no matter how efficient the chiller is.
Yellow-shaded cells show where chiller efficiency becomes the limiting factor. In these ranges, increasing the flow rate alone doesn’t help much unless you also improve the efficiency of the system.
Key Insight:
Where the gray and yellow cells meet, the system hits a performance stall point. For example:
In the efficiency columns, find where the grey and yellow cells meet. Any flow rate above that point (higher GPM) still takes the same amount of hours after the cells meet because the chiller isn’t efficient enough to take advantage of faster flow.
In the GPM row you can see the same effect, increasing efficiency doesn’t improve chill time because the flow rate is maxed out for that system size.
These stall points help identify the “bottleneck” whether it’s the pump (flow rate) or the chiller (efficiency) so we can adjust the system for faster cooling.
This visual breakdown helps answer the common client question: “How long will it take to cool my pool with a chiller in summer?” It also helps our designers in selecting the correct chiller model, calculating BTU needs, and optimizing for flow rate and energy efficiency.
The system is only as fast as its weakest link. If your flow rate is too low, the chiller can't move enough water through to cool the pool quickly, even if the chiller is working perfectly. At low GPM (like 20–35), flow is the bottleneck, not the chiller. So at those low flow rates, the time it takes to cool the pool stays very high, no matter how “efficient” the chiller is.
What You Should Consider Before Buying
If you're considering a pool chiller for a North Texas home, keep these realities in mind:
Run Time vs Effectiveness: You may run your chiller all night to gain just 2-3 degrees of cooling, only to lose it again by lunch the following day.
Electricity Cost: You're paying for hours of compressor time with minimal thermal benefit during the peak heat season.
System Design Limits: Units like the JRT3000 are not designed to handle sustained high ambient temperatures during the day.
Smarter Alternatives
While air-cooled chillers have their place, they may not be the smartest investment for every North Texas homeowner. Here are some more effective options:
Evaporative Cooling Features (fountains, waterfalls): More effective in low humidity and actively cool water. Evaporation can help cool by nearly 8,000 BTU’s per every gallon lost. This is the dominating method of cooling, especially when you replenish the pool with tap water. The average tap water temperature in North Texas is around 75°F. This means for every 1” of water you add you can see around a .5 degree temperature change.
Shade Structures: Reduce direct solar load and slow down heat gain. Important to consider when designing your pool.
Thermal Pool Covers: Prevent heat gain during the day and help retain cool temps overnight.
Hybrid or Water-Cooled Systems: More expensive but significantly more reliable in extreme climates.
Alternative Notable Manufacturers
Whaley Products, Inc. (McKinney, TX) Engineers and builds packaged water‑cooled chillers ranging from ~2 tons to 80 tons on skid-mounted units with stainless steel evaporators and Copeland scroll compressors. Customizable for pools, skid-mounted systems, experience with OEM/private-label residential applications.
https://www.whaleyproducts.com/
Master Chiller, Inc. (Garland, TX): Manufactures both water‑cooled and air‑cooled chillers, with full customization for process and HVAC needs, backed by installation, maintenance, and 24/7 support. Offers full customization including pool-ready systems, known to build systems for residential chillers.
https://liquidchillers.com/master-chiller-inc/
Cold Shot Chillers (Houston, TX): Known for heavy-duty custom water-cooled chillers, supporting wide industries since the late ’70s. Has a history of supplying water-cooled chillers for pool and spa use, can tailor to homeowner scale.
https://waterchillers.com/
Final Thoughts
The concept of a pool chiller sounds like the perfect solution, but in high-heat climates like North Texas, performance isn’t just about what the unit can do, it’s about what the weather allows it to do. Unless you understand the science, you may end up with buyer’s remorse and a hefty electric bill.
Always evaluate the relationship between air temperature, pool exposure, and equipment limitations before installing an air-cooled pool chiller. In most cases, strategic design adjustments and evaporative cooling offer better, more cost-effective results.
Ready to Take Control of Your Pool Temperature, No Matter the Texas Heat?
Don’t let scorching summers ruin your plunge. At Radelli Designs, we designr comfort with precision. If you're serious about year-round usability and performance, it’s time to explore the right chiller solution for your pool.
Contact us today to schedule a consultation and ask about our chiller performance calculator to see exactly what your pool needs!
