How to Lower the Temperature of a Pool – Multiple Methods

UPDATED: Nov 01, 2019.

When it comes to your pool temperatures, there are few times that you can say “My pool is actually too hot to swim in right now.” But if that does happen, what are your options? In this article we are going to explore just that. Some of the most common options are: add shade to the pool, ice in the pool, pool water spray system, heat/cool heat pumps, and evaporative pool chillers. This can really become a problem for a swimming facility who hosts a therapeutic class in the morning and then regular swims in the afternoon – the recommended temperature differences are up to four or five degrees.

Adding Shade

Adding shade to the pool may be one of the simplest ways to lower your pool’s temperature, if it is an outdoor pool. This can be done by taking what are known as “shade sails” or cabanas and putting them over all of the exposed areas of the pool. This would take only a couple of degrees from the pool over a 12-24 hour period. This is more for home pools, not commercial, as well as outdoor pools (obviously).

Adding Ice

Although this seems too simple to be true, it is actually an effective method if you get enough ice. That is the problem though – for any pool of size, it would take an incredible amount of ice to lower the heat of the pool even a couple degrees. So while this method may be the simplest, it is simply not as cost effective as it could be, and it takes a lot of resources. For a 100,000 gallon pool for one day would need close to 50,000 pounds of ice. That’s a lot of money to lower the temperature of your pool for a single day.

The equation for finding how much ice you would need for your pool to lower the temperature (you can use any temperature change) is the following: PV/1000 x TR x 4.375. PV stands for Pool Volume – so this number indicates the amount of gallons in your pool. TR is equal to temperature raise (or temperature change, really). So you plug in what difference you want for your pool temperature and then solve. The number you get is the amount of ice in pounds that you would need to do it. Crazy!

Pool Water Spray System

The idea of the pool water spray system is aeration. But exposing more water to the air, the temperature declines in a relatively rapid rate. When the water is exposed, more evaporation can occur, causing secondary temperature decline. The problem with this method is that the weather plays a major role in how successful it is. If it is extremely hot and humid, there will be very little evaporation, which means there will be very little temperature change.

This used to be the method of choice for commercial properties but has declined since the introduction of the heat pump, which has taken over as the best and easiest way to monitor and change the temperature of a pool. When it was used, the engineers would create an intricate display of the pipes used to aerate the water – the kids would love playing in the sprays, until the health department or other regulation agency stepped in and decided that the sprayers shouldn’t spray until the public is no longer around, limiting the usage of this method to closed hours.

Recently, there has been the development and the emergence of a portable aerator setup. The pump would be mounted to some sort of cart, with special spray nozzles attached and suction intake. But again, this method is regulated by the department of health to only be used during closed hours as well.

Heat/Cool Heat Pumps

This is the most commonly used method to regulate water temperature in pools. The heat pump works exactly the way that sounds – it heats the water in the pool as it runs through it. This works similar to the thermostat in a house, in that you can set one temperature and it will handle the pool to keep it within the range of the temperature selected. Some of these have the option to cool the pool, by housing a refrigerant that can be used to lower the temperature of the water. These are very cost effective and have been shown to be more resistant to corrosion when in contact with some chemicals, especially for salt water pools. Although they are more expensive to install in the beginning, they can easily pay for themselves over time, but will never be as cost effective as the evaporative pool chillers.

Evaporative Pool Chillers

These chillers are very similar to that of the original idea of the pool water spray system, which also worked through evaporation. But with this one, as the water comes through the chiller, a fan is used to blow onto the water, cooling it and causing the hotter water to evaporate. This can significantly lower your pool temperature. But because it works through evaporation, you will have to also continue to add water back to the pool to replace what is gone. Although in the beginning this is a very cheap option, it can put a lot of wear and tear on your pool pump because of the increased time that it will spend running. It is also extremely susceptible to corrosion in a salt water pool.

These are a few of your more mechanical options, but you do have some options that are more natural alternatives – these include letting your pool run all water features (such as fountains or sprayers or waterfalls) throughout the night, causing the water to decrease in temperature due to exposing it to the cooler air. You can also simply add water to the pool – if you put 2 inches of water into the pool, it can decrease the temperature by 1-2 degrees. You can run your pump at night, with the jets facing into the air, causing an increase in circulation. You can even run the pool cleaner or open the drain, because this causes the different thermal layers within the pool to equalize by stirring up the water. You can set up fans to blow across the top of the pool overnight, which will also increase evaporation. But the easiest way to lower the temperature of the pool would be to simply use it. By jumping into the pool, swimming, and splashing, the temperature and heat within the pool will be dispersed, lowering the pool’s temperature.

Well I hope that this article help gave you some ideas on how to lower the temperature of your pool! Lowering the temperature of your pool can be a serious task, but it is not an impossible one! There are even options that don’t cost any money – while the other options could easily be added to save you a headache and grief in the future. Let us know what you think about cooling your pool in the comments, and if you like the article feel free to share it!