Dehumidifier calculation for the indoor swimming pool.

Dehumidifier calculation for the indoor swimming pool.

Further to the last article, we will now understand the dehumidifier calculation. This chapter is about indoor pool dehumidification calculation. Hence, all specifics mentioned here about swimming pools only. As we all know, every pool needs an efficient drying system. Thus, the right capacity sizing is essential. To make things simple, you can use a dehumidifier calculator on our website. But, for the complex site, we need an expert hand.

For the right capacity selection, get in touch with the dehumidifier dealer. After the site visit, they can offer you the right solution.

Why do the dehumidifier calculations?

Every indoor pool room is a humid place. Thus, it is a paradise for mold, fungus, and germs. As a result, it gives rise to allergies. Also, high moisture causes the bad smell of chlorine and swelling of the woods. In short, high humidity brings lots of problems with it. An efficient pool room dehumidifier can remove wetness from the air. Hence, it can help you to avoid issues due to pool evaporation.

It is crucial to the right dehumidifier calculation. If over sized, then it will more initial and running costs. On the other hand, if undersized, then it will not remove humidity to the full extend. So, it is required to do proper sizing.

Swimming pool humidity control needs an efficient pool drying unit. We will learn how to do indoor pool dehumidifier sizing. But, we will use actual data. And arrive at proper indoor pool dehumidification calculation.

What is dehumidifier calculation data?

If we understand the source of humidity, then we can decide the correct data. In the pool room, the difference between space and water temperature creates evaporation. In other words, if the difference is more then evaporation will be more. Hence, the humidity level will increase in a short time. At the same time, the water surface area plays a crucial role. A more exposed water surface will generate more moisture.

The type of swimming pool also contributes to the effect. For example, activity in the residential pool will be higher than a hotel pool. Hence, we need to factor high uses while doing calculations. Thus, the intensity of uses considered in the form of “activity factor.”

Sizing factors.

Thus, we need to consider the following data for designing a dehumidifier calculator.

  • Area of a swimming pool. A larger size will generate more moisture. Hence, we need high dehumidifier capacity.
  • If water is hot, then it will evaporate at a fast rate. Thus, humidity inside the room will increase at a rapid pace. So, we need to consider the highest temperature of the water.
  • For the dehumidifier calculation, we need to consider room temperature too.
  • The type of swimming pool will decide the frequency of its use. 

With the above factors, we can do the proper sizing of the unit.

Dehumidifier calculator.

Now, let’s consider an example of a residential swimming pool. The current indoor pool humidity level is around 90% RH, and the owner wants it comfortable. For indoor pool rooms and spa, a comfortable humidity level is 60%RH. Thus, indoor swimming pool dehumidifiers should reduce humidity to 60% RH.

The size of the swimming pool is 10 meters by 5 meters. Please note that it is an uncovered pool. Hence, the exposed water surface area is 50 square meters. And, the air conditioner maintaining a room temperature of 25 degrees Celsius. Also, the pool water temperature is not more than 30 degrees Celsius. So, let us do the dehumidifier calculation.

The formula for dehumidifier calculation.

We are going to use a simplified equation. It is derived considering all factors. Thus, this method holds suitable for residential and commercial pools. The formula for calculation of indoor pool dehumidifier is as follows.

W= 15 x [Ax(Pw-Pa)Fa]


W’ is the evaporation rate in kg/hr or liter/hour.

‘A’ stand for pool water surface area in a square meter.

‘Pw’ denoted saturation vapor pressure taken at water surface temperature.

And, ‘Pa’ indicates saturation pressure at room air dew point.

The activity factor depends on the type of swimming pool, which is represented by ‘Fa.’

Calculation procedure.

To get the capacity of the swimming pool dehumidifier, let put values in the above formula. Area of swimming pool we can get from the site visit. To find out ‘Pw’, we need to refer to table 1. Find out its value corresponding to the temperature of swimming pool water. Similarly, the ‘Pa’ value can find out in Table 2. The corresponding value of ‘Pa’ for room temperature can find out.

Depending on the pool type, we need to select the activity factor for dehumidifier calculation. The activity factor depends on the number of people using the room and their activity. Hence, types of swimming pools are classified into broad seven types.

From Table 1, the value of ‘Pw’ at the swimming pool water temperature of 30 degrees Celsius is 0.0425.

Also, from Table 2, the value of ‘Pa’ at an indoor temperature of 25 degrees Celsius and the required humidity of 60% RH is 0.0190.

Since it is a residential pool, from the activity factor table, we can consider activity factor Fa=0.5.

When we put all value in the above formula, we get a capacity of 8.81 liters per hour, which equals to 202 liters per day.

The same Dehumidifier calculator can use for pool and spa.

For more information on the pool dehumidifier, please contact us.

Indoor pool dehumidifier calculation for humidity control.

Estimated reading time: 5 minutes