Self-powered humidistats


Room humidistats
Hygroswitch and HGMini, HG120



  • No auxiliary power
  • High humidity range: very good.
  • Long term stability: very good.
  • Robustness: very good.
  • Condensation: no effect.
  • Maintenance: don't care


Duct hygrostat
HG80






The POLYGA® fibers are longterm stable and watertight

Self-powered humidistats for
humidity control

For many monitoring tasks, nothing beats reliable mechanics - no power supply required.

Typically in these situations, the air needs to be monitored and controlled to regulate its humidity. These types of application are extremely common in a wide range of sectors, including museums, warehouses, production areas, ripening facilities for fruit and vegetables, the baking industry, mushroom cultivation and air conditioning of buildings. The humidifiers, fans, dryers or other devices used need to be controlled as the situation dictates.

The most cost effective solution

What is the most cost effective solution? A classic Galltec+Mela humidistat. Experienced, well informed users choose Galltec+Mela humidistats, because these products offer clear benefits and eliminate risks.

Galltec+Mela humidistats are fitted with the same robust POLYGA® humidity measuring element that are used in their air humidity transmitters. The measuring element is washable and specially designed for high air humidity. It is reliable, robust and built for a long service life. A simple and ingenious mechanism, proven in practice for over 35 years, activates a micro switch.

It couldn't be simpler: The change in the length of the measuring element activates the micro switch when the required air humidity is reached - and that's all there is to it! And it's totally reliable - with no electronics or auxiliary power.

POLYGA® -
the humidity measuring element

The humidity measuring element produced by Galltec+Mela under the name POLYGA® consists of multiple plastic mesh bands, each made up of 90 individual fibres with a diameter of 3μm. A special process imbues these fibres with hygroscopic properties so that they absorb and desorb moisture. The harp shaped measuring element inside the humidistats is protected from coarse dust and dirt and requires no maintenance whatsoever under normal indoor air conditions.

Galltec+Mela humidistats with the POLYGA® measuring element have proven their reliability over more than 35 years in a huge number of applications. These are classic humidity controllers built to a high technical standard.



To humidistat product overview

Humidistats with POLYGA® measuring element


Room humidistats

Duct humidistats

OEM modules

Dew point monitors





Hygroswitch, HGMini, HG120 HG80 HM80, HM120 FAS, FAS 250VAC
Easy installation, flush mounted cover, optional internal selector. No self-heating, washable humidity measuring element, breaking capacity up to 15 A (230 V AC). Modules for integration in a wide range of customer-specific standard products. Prevent damage due to condensation or high air humidity.





Possible applications


HVAC and building automation
  • Construction
  • Offices & public buildings
  • Hospitals
  • Private homes
  • Museums
  • Swimming pools & spa
Warehousing and Transport
  • Cooling & air conditioning in trains
  • Ship containers
  • Warehousing
  • Paper storage
Energy and environmental technologies
  • Electric control & switchboard cabinets
  • Wind power stations
Agriculture & food industry
  • Green houses
  • Storage & transport of fruits, vegetables, meat
  • Food technology
  • Fruit maturity
  • Bakery technology
Process and factory automation
  • Textile processing
  • Paper & print



Thank you for your interest.
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