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What is a Dehumidifier?
What is a Dehumidifier?

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What is a Dehumidifier?

Find out what a dehumidifier is, what one does, how one works & discover the different types that are available.

A dehumidifier is an appliance that removes moisture from the air within a space. They can be used in homes, offices, workshops, warehouses, construction sites, emergency sites, and more.

Dehumidifiers have an air inlet, internal fans, a dehumidifying system, a water management component, such as a collection tank, drain output, exhaust point, and an air outlet. 

Dehumidifiers come with a range of extraction capacities to suit various locations and for different applications.

What Does a Dehumidifier Do?

A dehumidifier lowers and controls the level of relative humidity within a space. You can use these machines for various applications, such as preventing the ill effects of too much moisture trapped in a space. Dehumidifiers can prevent condensation and damp in homes and commercial and industrial areas. They can improve the quality of air and alleviate allergy symptoms. Dehumidifiers help to preserve sensitive materials and protect equipment. They can dry out clothes, dry areas after leaks or floods, dry construction work such as wet trades and decorating. They can also dry materials during industrial processes, manufacturing, and food & drink production.

How Does a Dehumidifier Work?

There are 2 main types of dehumidifier - refrigerant and desiccant. Each type uses a different system to separate moisture from the air.

  • Refrigerant Dehumidifiers. Also called compressor dehumidifiers or condensation dehumidifiers, refrigerant dehumidifiers use a compressor that pumps refrigerant gas through a set of metal coils so that they are are the coldest surface in the space. A fan draws ambient air into the unit and passes it over the coils. The coils cool the moisture in the air to below its dew point, causing it to condense into a liquid. This moisture then drips away and is collected in a water collection tank or drained out from an outlet. The cold, dry air then passes through a warm condenser, which heats it, then a fan recirculates it back out into the space. The process continues over and over, lowering the relative humidity within the space.
  • Desiccant Dehumidifiers. Desiccant dehumidifiers use desiccant material on a rotary wheel. A fan draws air into the dehumidifier and passes it through the desiccant. The desiccant absorbs moisture from the air like a sponge and the dry air is recirculated into the space. The saturated desiccant wheel continues to rotate, and a stream of reactivation air and a heating element dry it out. The collected moisture evaporates and is removed from the unit as water vapour, allowing the desiccant to absorb more moisture.

What Are the Benefits of a Dehumidifier?

Using a dehumidifier to lower the relative humidity in an area has many benefits. Controlling humidity can prevent condensation, damp, mould growth, and other building blemishes that are signs of moisture damage. Moisture damage in any building can lead to uncomfortable surroundings, bad odours, and actual structural damage. Damage to paints and varnishes, deterioration of adhesives, swelling and warping of building materials like wood, damage to brick and concrete, corrosion of metal building materials, including wiring, can all be devastating to a home or a place of business.

Lowering the relative humidity in areas that contain sensitive materials, such as server rooms, galleries, libraries, museums, and other storage facilities, can be vitally important. The preservation of artwork, documents, and equipment can help to protect valuable and significant items, and prevent disruption to online services.

Dehumidifiers can have health benefits, as high humidity can trigger allergic reactions. Humid areas are playgrounds for dust mites, mould spores, pollen, pet dander, pests, and other allergens. Preventing the growth and circulation of pollutants can alleviate symptoms, such as sneezing, coughing, sore eyes, itchy skin, and more.

Dehumidifiers can help to dry out damp areas quickly and effectively. Whether a room has suffered from a leak or flood, or you are drying construction work, such as screed, plaster, paint, concrete, wallboard, a dehumidifier can elevate the drying process. You can use a dehumidifier on its own or alongside a heater and fan, allowing you to quickly remediate and dry spaces, stay on schedule, and prevent cracking or distortion.

Where Can I Hire a Dehumidifier?

With over 400 tool hire shops nationwide, National Tool Hire Shops offers DIY and Trade customers a convenient tool hire service, with over 2,000 products available, including dehumidifiers.

How Much Does it Cost to Hire a Dehumidifier?

Depending on the size of the unit, extraction capacity, and the length of the hire period, you can hire a dehumidifier from as little as £40 per day.

Prices may vary due to location and availability. Check our range below to see what you can book in your area.

If you have long-term concerns and would like to purchase a dehumidifier, Climate Dry and National Heater Shops are drying and climate control specialists, with excellent product ranges.