1. Are you a manufacturer or a trading company?

Preair is a dehumidifier manufacturer with over 20-year experience on the design, mould, tooling, R&D, production, quality checking, after-sales service, having strong capacity to provide OEM & ODM solutions for you.

2. How can you guarantee the production quality?

Preair strictly follows the standard of below procedure to ensure the quality.

IQC -- Incoming Quality Control

PQC -- Production QC

OQA -- Out Quality Assurance

DQA -- Development Quality Assurance

IPQC -- In Process Quality Control

Laboratory -- Product Laboratory

3. What's the warranty period?

One year from the shipping date.

4. Do you provide free samples ?

For customers who cooperate with us for the first time, Preair will charge sample fees and freight. The samples will be delivered within 3-5 working days after delivery test. If you are satisfied with the quality of the sample and place a batch order, we will refund the sample fee.

5. Do you accept small quantity for trial order?

Preair accepts small trial orders to support your business. However, please note that in our peak season, conditions can be arranged depending on your required machine model.

6. What is the lead time ?

The lead time depends on the required machine model. the lead time of some finished products takes 1 week, some customized products more than 30 days, large orders 35 days.

7. What is your payment term for bulk orders ?

Preair accepts 30% T/T in advance, balance against the copy of B/L Or L/C at sight.

8. How do you ship the goods?

DHL, UPS, FedEx, TNT, Airline, Train,and sea shipping also optional. You can also send your shipping agent to pick up the goods.

9. Do you accept private label on product?

Private label is acceptable.

10. Do you accept color box packing when quantity is below MOQ?

Most of our products come with free white boxes. We can make color boxes, but the cost of printing will be included in the unit price.

11. How to Clean Dehumidifier?
  1. Turn off and unplug the dehumidifier from the power source.
  2. Remove the water collection bucket and empty any water inside.
  3. Use a soft cloth or sponge to wipe down the interior surfaces of the dehumidifier, including the coils, fins, and reservoir. Be gentle and avoid using abrasive cleaners that can damage the surfaces.
  4. Allow the dehumidifier to air dry completely before reassembling and using it again.
12. How Big of a Dehumidifier Do I Need?

The size of the dehumidifier you need depends on several factors, including the size of the space you want to dehumidify, the level of humidity in the area, and the specific use case. It's important to choose a dehumidifier with the appropriate capacity for your needs to ensure that it effectively removes moisture from the air and helps prevent mold and mildew growth.

13. How Much Does a Dehumidifier Cost?

The cost of a dehumidifier varies depending on several factors, including the brand, model, features, and capacity. Some factors that can increase the cost of a dehumidifier include additional features such as automatic shutoff, digital controls, and air purifying functions. Some high-end models may also come with built-in humidistats or Wi-Fi connectivity for remote control.

14. How to Use Dehumidifier?
  1. Make sure the dehumidifier is plugged in and turned on.
  2. Set the desired humidity level using the controls on the unit. The ideal humidity level for most indoor spaces is between 30% and 50%.
  3. Let the dehumidifier run for at least 24 hours, or until the water collection bucket is full.
  4. Check the air filter on the dehumidifier periodically and clean or replace it as needed.
  5. If your dehumidifier has a drain hose, connect it to the unit and run the hose to a nearby drain or sump pump.
  6. Monitor the humidity levels in the room using a hygrometer. 
15. Where to Place Dehumidifier?

The placement of your dehumidifier is an important factor in its effectiveness. Here are some tips for where to place your dehumidifier: Place the dehumidifier in the area with the highest humidity levels. Make sure the dehumidifier is positioned at least 6 inches away from walls and other objects to allow for proper air circulation. By placing your dehumidifier in the right location, you can maximize its effectiveness in reducing humidity levels and preventing mold and mildew growth.

16. Where to Put Dehumidifier in Basement?

Place the dehumidifier in the center of the basement, away from walls and other objects to allow proper air circulation.

17. How to Work a Dehumidifier?

To use a dehumidifier, place it in the area with the highest humidity levels, turn it on, and set the desired humidity level using the controls on the unit. Let the dehumidifier run for at least 24 hours, or until the water collection bucket is full, and then empty the bucket. Check the air filter periodically and clean or replace it as needed to ensure the dehumidifier is operating effectively.

18. Why Is My Dehumidifier Not Collecting Water?

There are several reasons why your dehumidifier may not be collecting water: The humidity level in the room is already low. The temperature in the room is below 60 degrees Fahrenheit. The air filter is clogged or the intake or exhaust grilles are blocked. The refrigerant coils or compressors are damaged. The dehumidifier is not installed correctly. Etc.

19. Do dehumidifiers work in low humidity?

Dehumidifiers are effective in environments with high humidity and can be crucial for controlling mold growth and preventing other moisture-related issues. 

Suppose you want to use a dehumidifier in a low-humidity area. In that case, it is recommended to measure the RH level of the area repeatedly and choose a dehumidifier that can still work in a relatively low-humidity condition. The WH, ZETA and CFZ series of dehumidifiers can work between the 10%-90% RH. Want to buy efficient and powerful dehumidifiers? Contact Preair first.

Dehumidifier Model








Functioning Temperature Range








Functioning Humidity Range








20. How much does a whole home dehumidifier cost?

Preair provides high-quality whole home dehumidifiers at an ex-factory price. The specific price you can find at our online shop on Alibaba.

21. What size dehumidifier do I need?

Preair provides highly efficient LGR dehumidifiers for professionals to cope with water damage, fire damage, mold growth, air purification, etc. Take the LGR dehumidifiers for example, you can choose a dehumidifier with a specific dehumidification capacity according to the size of a space that you want to dehumidify. There are other factories that you need to take into consideration, such as, the current RH level, the desired RH level, ventilation conditions, and budget.







Dehumidification Capacity

(26.7 ℃/60% RH)

85 PPD

105 PPD




Size For

1,000 - 2,000

square feet

1,000 - 2,500

square feet

2,500 - 4,000

square feet

3,000 - 6,000

square feet

3,500 - 7,000

square feet

22. Why You Are Recommended to Choose the Preair Dehumidifier?

Reliability and Quality Assurance:

Preair has a history of producing reliable and high-quality products. We invest in research, development, and quality control processes to ensure our products meet certain standards.

Customer Support and Service:

Preair has established customer support channels, making it easier to get assistance with any issues, including troubleshooting, repairs, or warranty claims.

Warranty and Guarantee:

Preair offers warranties that provide additional peace of mind for consumers. This means that if the dehumidifier experiences any issues within a specified time frame, the manufacturer will repair or replace it.

Availability of Parts and Accessories:

Preair has a steady supply of replacement parts and accessories, making it easier and more convenient to maintain and repair the dehumidifier if needed.

Performance and Efficiency:

Preair often invests in research and development to create dehumidifiers that are more efficient and effective in removing moisture from the air.

23. Do dehumidifiers lose efficiency over time?

Yes, dehumidifiers can lose efficiency over time due to several factors:

-- Dust and Dirt Buildup

-- Refrigerant Leakage

-- Wear and Tear

-- Clogged Filters

-- Humidity Levels (used in extremely high humidity conditions for extended periods)

-- Age

-- Lack of Maintenance

Environmental Conditions (in extreme temperatures or conditions outside of its recommended range)

24. Should dehumidifiers make noise?

Yes, it is normal for dehumidifiers to make some level of noise during operation. This noise is primarily generated by the fan and the compressor components of the dehumidifier.

While some noise is to be expected, excessively loud or unusual noises can indicate a problem with the dehumidifier and may require attention or maintenance. If you notice any sudden changes in the noise level, it's a good idea to check the unit for any loose components, debris, or signs of wear and tear. 

25. What features to look for in a dehumidifier?

When selecting a dehumidifier, it's important to consider several features to ensure it meets your specific needs. Here are some key features to look for:




Continuous Drainage Option

Portability and Wheels

Filter Indicator Light

Noise Level

Energy Efficiency

Timer and Delay Start


Built-In Pump

Digital Display and Controls

Air Filtration


26. How does a dehumidifier humidistat work?

A humidistat in a dehumidifier is a sensor that measures the relative humidity (RH) level in the air. It works in conjunction with the dehumidifier's control system to maintain a desired humidity level set by the user. Here's how it works:

-- Sensing Humidity Levels

-- User-Set Humidity Level

-- Comparison and Control

-- Cycling On and Off

-- Maintaining Constant Humidity

27. What should the temperature be on a dehumidifier?

The operating temperature of a dehumidifier can vary depending on the specific model and type, but most standard refrigerant-based dehumidifiers are designed to operate effectively in temperatures ranging from approximately 41°F (5°C) to 95°F (35°C).

28. How many watts is a dehumidifier?

The power consumption of a dehumidifier can vary widely depending on its capacity, features, and the manufacturer's design. Generally, residential dehumidifiers can range from about 300 watts for smaller units to 1,000 watts or more for larger, higher-capacity models.