Evaluating Relative Humidity: Factors and Measurements

There are a lot of factors affecting the cooling performance of an air conditioning unit, such as the relationship between dry bulb temperature, wet bulb temperature, relative humidity, and dem point temperature. Making sure that these facets are good to add to the overall performance of the unit and, essentially, occupant comfort.

To make sure that an air conditioning unit is running at maximum capacity, HVAC technicians usually use a sling psychrometer and psychrometric chart. These devices are also called “humidity” meters, and in order to make sure that your unit is still working great, you need measuring devices that are accurate, more convenient to use and can be used in various locations even unsuitable for sling psychrometers.

If you want to do an HVAC evaluation and diagnostics on your unit, you need a device, such as the Fluke 971- a measuring device that can calculate wet bulb temperature and dew point temperature.

To better understand how to properly measure and evaluate your air conditioning unit, here are key terms you need to be familiar with:

Wet Bulb

Closely related to enthalpy or the total heat in the air (dry bulb and wet bulb). In a psychrometric chart, the wet-bulb lines are nearly parallel to the enthalpy scale and values.

Dew Point

This is critical in both hot and cold weather evaluations. Duct surface temperature must be maintained above the dew point to prevent condensation whether inside or outside of the conditioned space.

Relative Humidity

This must be kept low enough to ensure inside wall and window surface temperatures do not approach dew point. If condensation appears on window or wall surfaces, condensation hidden within envelope walls will be likely.

If you want to do an HVAC evaluation and diagnostics on your unit, you need a device, such as the Fluke 971- a measuring device that can calculate wet bulb temperature and dew point temperature. Visit www.presidium.ph and view our wide range of measurement devices that will suit your needs.