Many New Zealand homes suffer from cold, damp and mould-ridden homes during the winter which can cause respiratory health problems. This can be due to poor insulation and ventilation and is made worse when residents cannot afford heating. The main aim of this paper is to modify an existing dehumidifier which can remove moisture, heat the home and reduce the mould and bacteria. To achieve that we combined the properties of a dehumidifier with ultraviolet germicidal lights (UV), which have been proven to effectively destroy the DNA of mould and bacteria. The result shows that the device reduced the mould growth and did increase the room temperature. This due to the fact that the dehumidifier captured 2 litters of water over 24 hours of testing. This shows that the device did improve the indoor air quality (IAQ) in the room.