What is a Dehumidifier?

A dehumidifier is an electronic appliance which removes and maintains levels of humidity in the air, reducing condensation, excessive moisture, and dampness. The water is removed from the environment to a level which is pre-set on the dehumidifier by the user.

Just manually dispose of the collected water when the tank is full, or hook up a hose so it empties automatically (which is great for really high humidity).

Dehumidifiers are commonly used in high-humidity areas, such as older homes with poor ventilation and high levels of condensation in winter. People may also use them when drying clothes indoors or if they have allergies which are exacerbated by humid conditions.




What causes high humidity?

In most cases, high humidity will be a fault in the structure of the house. Porous walls, water leaks, poor ventilation, and rising damp can all increase the humidity to levels that are sometimes undetectable but still too high.

  • SPEEDY TOP TIP: The ideal level of humidity in a home is between 30% and 50%

Showering in a bathroom with no window or fan and the door closed, and cooking in the kitchen with boiling pans and steam from the oven, are just two of the easiest ways humidity can build up in a home. Drying clothes inside over the winter months can also release two litres of water into a home!

Humidity can also build up during renovation work if materials such as paint and plaster are not given sufficient time to dry. This won’t be detectable for a little while but can cause severe issues in future. Using a dehumidifier when decorating can help speed up the drying process.

If you rarely open windows wide enough for a sufficient fresh flow of air in your home, this can also cause damp problems to develop. This is particularly relevant in winter when it is cold and we have heaters and central heating on.

High humidity becomes noticeable if your walls are looking and feeling damp, the air feels clammy and warm, and there is a horrible damp smell. Mould can develop when the humidity is at around 68%.

This is when you really need to act; however, maintaining a suitable level of humidity in your home is something that should be regularly monitored throughout the year to prevent issues in the first place.


What are the benefits of a dehumidifier?

Using a dehumidifier can reduce humidity levels and the risk of mould, mildew, and odours, which often come with high humidity.

A big benefit is that humidity is reduced to a suitable level. So the air won’t feel too dry (which could cause dry skin, irritated eyes and breathing difficulties). You still need a certain level of moisture in the air.

Too much humidity in a house can cause:

  • Damp and mould
  • Condensation on windows
  • A musty odour
  • Clammy feeling in the air

Prolonged cases of high humidity may cause structural damage to the home or room through damage to walls if they become too damp to damage to woodwork and structural support if it rots. You really don’t want to get to this stage.

Controlling the humidity day to day makes living conditions a lot more comfortable. The ability to treat the air in your room means any harmful particles, such as bad smells or allergens, are reduced.

This is particularly relevant to anybody with allergens such as dust mites, dander, or pollen. Drying out the air can help keep the things which set off your allergies at bay. It will also keep mould away, which is a perennial allergen throughout the year. It’s thought 1 in 5 people suffer from a mould allergy.


When should you use a dehumidifier?

Dehumidifiers can be used to remove excess humidity from the air. This may be when:

  • Drying clothes indoors
  • Decorating, plastering, and painting
  • Recovering from a flood or other water damage
  • Allergies are at their most severe
  • You see signs of damp in the home

But a big question is whether to use a dehumidifier in summer or winter. This is particularly relevant if you’re hiring one from Speedy Services for a short period. The answer can actually be to hire one in both seasons!

Winter is the most common time for dehumidifier hire in the UK. This is when we start to see condensation on the windows, damp on our walls with a lack of fresh air, and we have to dry clothes indoors. But in the rest of Europe, summer is also a popular time to use dehumidifiers.

Using a dehumidifier can help reduce that sticky, clammy feeling we can feel from the warm air outside. If you feel sweaty constantly, and the air feels really humid, a dehumidifier can (unsurprisingly) get rid of this humidity from the warm air.

As the UK starts to heat up in the summer months and feel the effects of temperatures around 40°C, using a dehumidifier can help when you’re struggling the most. Using a dehumidifier every 6 months or so can also help keep any risks of humidity, dampness, and mould at bay.



Does a dehumidifier cool a room?

Dehumidifiers are designed to remove excess moisture, not cool a room. So, if you need to cool your home down during a summer heatwave, opt for an air conditioner instead.

While you will feel a lot less muggy and damp in a heatwave when the air is dryer, a dehumidifier doesn’t actually cool the room or change the temperature.


Can a dehumidifier stop mould?

Mould will spread and grow in the right conditions. This is often high humidity and low fresh airflow. A dehumidifier can't stop mould growing, but it can help to reduce its spread by reducing humidity.

To fully remove mould, you need to understand the source. This could involve making structural changes to your home.


Should I use a dehumidifier in summer or winter?

A dehumidifier is designed to reduce excess humidity. High humidity can occur in both summer and winter due to either higher temperatures in summer or the use of central heating and closing windows in winter.

So, use a dehumidifier any time you feel the humidity in your home is too high. In winter, this may be when drying clothes indoors or having windows closed. In summer, a dehumidifier can also help reduce allergens such as pollens by improving the air quality.



Yes. Speedy, the UK's leading tool hire company, have a range of dehumidifiers for hire nationwide. Speedy has more than 200 service centres across the nation, hire counters in selected B&Qs and nationwide 4-hour delivery; dehumidifier hire has never been easier.

  • You’ll find all the tools you need right here. Why not start planning your next DIY project and open a Speedy account today online and in-store.
  • Visit our YouTube account for more DIY tips and How-To guides.
Speedy in your pocket
Get a Speedy Account