What is the relationship between indoor air temperature and humidity in a closed environment inside a building. Also what affects them both in a residential indoor environment?
Humidity and temperature are only related if using certain measures of humidity, e.g. the relative humidity. The latter always relates the actual specific humidity to the saturation specific humidity. The latter is temperature dependent and consequently the relative humidity. If temperature rises, the saturation specific humidity rises as well and consequently the relative humidity decreases for unchanged water vapour amount.
Beside the physical relationship between air temperature and humidity, user behaviour in indoor environments plays an important role too. Just imagine bath rooms or kitchens. Through for example showering or cooking, user influence indoor climate and humidity increases rapidly.