How to Choose the Best Dehumidification Strategy for Water Damage Restoration: A Complete Guide

After water damage occurs, drying the building efficiently and quickly is crucial for all involved:

• Residents may be temporarily relocated and want to return to normal life as soon as possible.
• Dehumidifier rental companies need to complete the job swiftly to rent out the machines again.
• Restoration companies aim to finish the job quickly to generate revenue.
• The building itself needs to be dried quickly to avoid long-term damage such as mold and mildew.

Choosing the right dehumidification technology plays a critical role in the speed and effectiveness of the drying process. The following examples highlight how different dehumidification strategies can vary in efficiency (refer to the guide below for calculations):

Example 1: Munich in September

• Average indoor humidity: 56%RH
• Ideal drying setpoint: 46%RH
• Temperature: 23°C

Comparing Cotes CL26 with a typical high-end condensation dehumidifier*

 * The condensation dehumidifier is rate for 1,8L/h at 30°C and 80%RH.

Example 2: Paris in February

• Average indoor humidity: 48%RH
• Ideal drying setpoint: 38%RH
• Temperature: 20°C

Comparing Cotes CL26 with a typical high-end condensation dehumidifier*

Parameter	Cotes CL26	Condensation Dehumidifier
Capacity [L/h]	1.12	0.29 (-75%)
Time to remove 100L with one DHU [h]	90	>300 (+233%)
Number of dehumidifiers needed	1	3-4
Investment to remove 1L/h [EUR]	1,075	4.655 (+330%)
Mass of dehumidifiers [kg]	10.9	166 (+1.423%)
Energy consumption [kWh/L]	1.12	3.1 (+177%)

 * The condensation dehumidifier is rate for 1,8L/h at 30°C and 80%RH.

Note: Most condensation dehumidifiers lose capacity at humidity levels below 40%RH, which can lead to inflated performance claims in real-world scenarios.

 

Guide for Choosing Technology

This guide is based on the ANSI/IICRC S500, PAS 64:2013 and ISO 13788 standards. It will walk you through the following steps:

1. Setting Drying Goals
2. Defining the Room’s Humidity Setpoint
3. Choosing the Best Dehumidification Technology

1. Setting Drying Goals

Before restoration begins, it’s essential to agree on the drying goal with the client and insurance company. Is the aim to fully restore the building to its pre-damage condition, or can slightly higher moisture levels be accepted?

• Full Restoration: Restoring to pre-damage humidity levels is the safest option to avoid future mold growth or structural issues.
• Higher Moisture Acceptance: If higher moisture content is accepted, ensure a clear agreement on how much higher and who will be responsible if future problems arise.

Recommendation: Cotes advises restoring the building to its original moisture level to ensure long-term safety and avoid mold risks.

2. Defining the Room’s Humidity Setpoint During Drying

Before water damage occurs, the humidity levels of both the air and the building materials (walls, ceilings, floors) are in balance. This balance is known as Equilibrium Moisture Content (EMC). When flooding or water damage happens, this balance is disrupted, causing an excess of moisture in the building materials.

To restore this balance, the air must be dried, which in turn pulls moisture from the materials, helping the space return to its normal condition.

How to Speed Up Drying: To accelerate the drying process, Cotes recommends setting the room’s relative humidity to 10% lower than its pre-damage level. This increases the moisture extraction rate, reducing drying time and restoring the building faster.

To make this process easier, we provide a humidity setpoint map that converts meteorological data into the recommended indoor climate settings, based on the ISO 13788 standard. This tool helps you quickly find the ideal humidity level for your specific location and situation.

Find the map here: cotes.com/map2 

3. Choosing the Right Dehumidification Technology

When choosing a dehumidifier, consider the following factors:

• Investment cost
• Energy consumption
• Ease of use

Always compare dehumidifier performance under the same drying conditions. For example, if drying at 20°C and 46%RH, the dehumidifiers should be compared at these settings. Many condensation dryers are rated for 30°C and 80%RH, which aren't realistic conditions for most drying situations. Below is a comparison based on capacity curves from a leading condensation dehumidifier.

 

Investment Cost

The investment needed to remove 1 litre of water per hour can vary significantly based on humidity levels.

Note: The price of the condenser dehumidifier is based on a comparison of six different models, resulting in an average investment of EUR 750 per litre of water removal capacity at 30°C and 80% relative humidity.

Conclusion: Cotes CL26 provides the best value for money in humidity conditions below 80%RH, which is standard for most restoration scenarios.

 

Energy Consumption

Energy efficiency is crucial for controlling costs and sustainability.

Conclusion: The Cotes CL26 is the most energy-efficient and sustainable option for relative humidity levels below 65%RH (or 60%RH at 23°C), which are commonly recommended across most of Europe.

 

Weight, Ergonomics, and Safety

The total mass of the dehumidifiers impacts both the project’s cost and safety during handling and transport.

Conclusion: The Cotes CL26 is by far the lightest solution across all humidity levels. It’s the only dehumidifier that doesn’t require lifting equipment and can be easily carried, even in buildings with stairs.

 

Ease of Installation

Condensation dehumidifiers are popular due to their simplicity of installation. However, the Cotes CL26 is equally easy to set up with its patented window kit, which takes only 30 seconds to install.

Learn more about the installation process here: How to setup the Cotes Window Kit with a Cotes dehumidifier in 3 easy steps

   

Final Considerations

• Preventing Cracking in Materials: To prevent cracking during the drying process, Cotes recommends using additional fans. Ensure a 3 m/s airflow on wet surfaces, reducing to 0.75 m/s once dry.
• Condensation Dehumidifiers at Low Humidity: Condensation units become inefficient below 40%RH and at temperatures below 15°C. In such cases, desiccant dehumidifiers like Cotes outperform significantly.

Conclusion

Selecting the right dehumidification technology for water damage restoration depends on the drying goals, room humidity levels, and environmental factors. The Cotes CL26 is highly efficient and cost-effective for most drying scenarios, especially at lower humidity levels. In contrast, condensation dehumidifiers may perform well in higher RH environments but often lose efficiency below 50%RH. Follow these guidelines to ensure a safe, fast, and cost-efficient drying process.

 

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* All graphs and calculations are based on performance data from a high-quality condensation dehumidifier made by a leading European manufacturer. Most comparable dehumidifiers are expected to perform at a similar level or worse, particularly when humidity drops below 50% or temperatures fall below 15°C.

** Please note: Most condensation dehumidifiers struggle to perform in low humidity. Our tests show that many models fail to produce condensation at 20°C and 40%RH, effectively turning them into expensive fans at these conditions.