You are surely familiar with a thermostat: it sets a temperature and ensures the heating switches on and off to maintain it. A humidistat does exactly the same thing, but for humidity instead of temperature.
What exactly is a humidistat?
A humidistat is a sensor with a controller that measures the relative humidity (RH) in a room and switches a device on or off based on that. For a dehumidifier, this means you set a desired humidity level, for example 55 percent, and the device determines for itself when it needs to run to reach and maintain that value.
Separate component or built-in
A humidistat can be a separate, external device that you connect to, for example, a ventilation system, but in most home-use dehumidifiers, the humidistat is built in as standard. You often see this as an adjustable percentage on the device's control panel or display.
Why is a humidistat useful?
Without a humidistat, a dehumidifier would have to run continuously, or you would constantly have to estimate when the device should be turned on or off. With a humidistat, this happens automatically, which offers a few practical benefits:
- No excessive drying: the device stops as soon as the set value is reached, so the air does not become unnecessarily dry.
- Lower power consumption: the device only runs when necessary, rather than continuously.
- Less maintenance: you set the desired value once and the device handles the rest itself.
How do you use a humidistat in practice?
First, set a target value that suits the room. For a living room or bedroom, a value between 45 and 60 percent works well for many people; in a basement or laundry room, you might temporarily choose a lower value to remove moisture faster. Keep in mind that the humidistat works with a small margin: for example, the device may only switch back on once the humidity rises a few percent above the set value, rather than exactly at the set point. This is normal and prevents the device from clicking on and off continuously.
Check occasionally with a separate hygrometer
The sensor in a humidistat measures humidity right at the device. In a large room, the value elsewhere might differ slightly. A separate hygrometer on a cabinet or nightstand, for example, gives you a good picture of the humidity in the rest of the room.
Humidistat versus timer: not the same
A timer and a humidistat are sometimes confused, but they do very different things. A timer switches a device on and off based on a pre-set time, regardless of the actual humidity. A humidistat, on the other hand, looks at the current humidity and reacts accordingly. In practice, a humidistat for dehumidification is usually more useful than a timer, because the need for dehumidification varies per day and per season. Some devices combine both functions, allowing you, for example, to set the device to only react to the humidistat at night.
Our advice
Do you want this handled without any hassle? Choose a dehumidifier with adjustable humidity control, such as the Dynter AirPure DH251. You set the desired humidity once, and the device then maintains it automatically, without you having to think about it constantly.