Abstract: An apparatus for measuring moisture in a gas flowing in one direction through an enclosed chamber includes a moisture sensor placed in the chamber. The moisture sensor includes a first and second electrode supported by a non-conductive member. Each of the first and second electrode has at least one elongated finger and a coating made of a moisture absorbing material. At least one elongated finger of the first electrode is substantially parallel with at least one finger of the second electrode. The apparatus further includes a gas temperature sensor, a moisture sensor temperature sensor, and a cooling element for controlling the temperature of the moisture sensor based on the data from the gas temperature data and moisture sensor temperature data. Further, the apparatus includes a source of electrical current providing a voltage across the first and second electrode.