Which water to use for evaporative cooler?

In this article, we explore the ideal type of water for the operation of evaporative coolers. We will delve into the importance of using water as a natural coolant to lower the air temperature in work environments, the differences between soft water and hard water, and how these can affect the performance of the cooler.

Being able to breathe clean air in indoor work environments and striving to reduce CO2 emissions are aspects of fundamental importance and great relevance for entrepreneurs. These priorities can be met by evaporative cooling, which uses the most natural and sustainable element on Earth as a refrigerant: water.

Water, a current issue that involves us all, is the ultimate source of life that we must strive to protect and preserve for as long as possible. For this reason, in this article, we want to delve into some topics that link water to industrial fixed coolers in order to clarify which type is best to use for these cooling systems and how to preserve water waste.

The importance of water in evaporative coolers

Water is the cornerstone on which the operation of evaporative coolers is based.
Evaporative coolers utilize the natural principle of water evaporation for their operation. Water serves as a natural refrigerant in this process.

Each unit draws in hot air from the outside, which, after filtration, passes through water-saturated honeycomb panels. The air, propelled by the fan, transfers some of its heat to the water contained in the evaporative pads, thereby lowering its temperature. The cooled air is then released into the workspace at more comfortable temperatures.

If you want to discover what evaporative cooling is, how it works, and its benefits, click here

Evaporative cooling: what it is, how it works and why to chooese it

Based on this concept, we understand how choosing the right type of water can significantly impact the performance of an industrial evaporative cooler and, consequently, the maintenance costs.

Water quality and its impact on cooler performance

Not all water is created equal. There are primarily two main groups: soft water and hard water.

Hard water is defined as water containing higher levels of certain minerals, such as calcium and magnesium, which, if accumulated within the components of the cooling system, can cause a general decrease in performance.

On the other hand, soft water, like rainwater, has a low mineral content, allowing the cooling system to operate under optimal conditions, thereby increasing efficiency and preserving components, thus reducing operating costs.

differences between hard water and soft water

Water hardness and deposit formation

In conditions where the hardness of the feed water for the evaporative cooler is particularly high, deposits of limestone may accumulate inside the unit, compromising its performance.

During the cooling process, water evaporation helps cool and humidify the air inside the unit, but at the same time, it leaves behind all the minerals present in the water itself. These minerals, considered “hard,” deposit inside the unit, mainly on the evaporative pads and various components, creating limestone deposits that can affect the performance of the cooler.

Among the main damages caused by limestone buildup are:

  1. Reduction in airflow: Limestone accumulating inside the cooler clogs the tubes and filters. This slows down the airflow, decreasing cooling efficiency.
  2. Lower cooling efficiency: Limestone prevents water from evaporating properly, reducing the cooler’s ability to lower air temperature.
  3. Equipment damage: In some cases, limestone can damage the internal components of the cooler, reducing its lifespan and functionality.
Damage caused by limescale in coolers

What water to use for the cooler?

To ensure optimal performance of air coolers, we recommend using drinking water with the lowest possible mineral content to minimize limestone formation.

Absolutely don’t use seawater or water containing chemicals! The components inside the evaporative cooler could corrode or be irreparably damaged.

In case the water hardness is particularly high, it is advisable to install a water softener at the water supply inlet. Additionally, it is recommended to frequently check the condition of the cooling units during the summer season, paying particular attention to the conditions of the evaporative pads and the water tank, where limestone deposits are more likely to occur.

How Carlieuklima evaporative coolers prevent limescale formation and growth

Another aspect related to water usage in industrial coolers, besides limescale formation, is the proliferation of mold and bacteria that can compromise the system’s operation and harm employees’ health. As we know, water provides an ideal environment for mold and bacteria growth, especially if it becomes stagnant.

The Eucold evaporative cooler is equipped with a self-cleaning system for the evaporative group and the water collection tank, which automatically activates at programmable intervals to maintain a high level of cleanliness and saturation efficiency.

An automatic self-cleaning cycle occurs every 4 hours: the machine suspends its evaporation cycle for a few minutes, the water inside the cooler is discharged, and replaced with clean water, which is then circulated through the evaporative pads to clean mineral residues and other deposits.

The repetition of these washes prevents the crystallization of minerals and other elements on the evaporative pads and throughout the system, ensuring long-term durability and maintaining high cooling efficiency.

Furthermore, each time the cooler shuts down, a final washing cycle is performed.

At the end of the washing cycle, the cooler drains all the water inside to prevent potential stagnation, which could lead to the development of viruses, bacteria, and the formation of limescale deposits.

Self-cleaning cycle of the evaporative cooler

How Eucold evaporative coolers reduce water waste?

Another aspect widely discussed when it comes to evaporative cooling is the significant amount of water used for its operation.
It’s certainly a sensitive and timely issue that the company has never ignored, but has actively sought effective solutions over the years to minimize water waste as much as possible.

Eucold evaporative coolers are equipped with a specific function called Water Saving, which optimizes the amount of water used, drastically reducing waste to almost zero. The goal is to avoid automatic water replenishment in the final stages of a cooling cycle, allowing the tank to be completely empty or nearly empty by the next Timer-OFF phase.
In this way, at the time of the next programmed discharge, the amount of water released by the system becomes almost zero, and consequently, negligible.


The water used for the operation of an industrial evaporative cooler plays a crucial role in ensuring optimal performance and prolonged device lifespan. Using the right type of water and understanding the difference between freshwater and hard water can make the difference between efficient, consistent cooling and recurring maintenance issues.

If you want to learn more about Eucold evaporative coolers and discover how Carlieuklima can help meet your cooling needs, we invite you to visit our dedicated product page. There, you can explore the features of our coolers and find out which solution might be best for you.


Eucold water evaporative coolers are the most sustainable, effective, and cost-efficient solution for summer conditioning of industrial warehouses, warehouses, hangars, and railway workshops.


Alternatively, feel free to contact us directly to request a free, personalized quote. Our technicians will provide tailored solutions for your needs, ensuring comfort and efficiency in any workspace.