Temperature and humidity control are two main advantages of modulating HVAC systems, but these concepts are sometimes too abstract for homeowners during the HVAC system purchasing process. As integral aspects of in-home comfort, it is important to demonstrate how temperature and humidity control can affect daily life. While a fixed speed HVAC system can only run at full speed, a modulating system can have two or more speeds. In terms of temperature control, this means a modulating system will provide consistent air conditioning that is commensurate with the need in the home, as opposed to fixed speed’s all-or-nothing method. A homeowner would notice this difference most in the rooms that receive the least airflow, which often leads to hot or cold spots.

Ask: Have you experienced hot or cold spots at home?

Another instance when having consistent airflow can impact quality of life is during the night, when comfort can directly relate to the ability to sleep. A fixed speed system can cause a homeowner to be both too hot and too cold, depending whether the system is cycling on or off. Increased cycling also creates a sound nuisance that can bother homeowners and even their neighbors. Conversely, a modulating system can provide a longer lasting and less intense airflow, which keeps rooms at a more precise temperature and allows its patrons to have better comfort control while they sleep, with fewer cycles than a fixed speed unit.

Ask: Does the noise of your AC unit cycling on and off keep you up at night, or startle you during awake hours?

Humidity manifests itself in different ways in the home. In terms of comfort, humidity increases how warm an environment feels, and also can lead to the sensation of clamminess. Since modulating HVAC systems run more consistently, more air is cycled through the system, which removes moisture, and a lower indoor humidity is achieved. And who can forget the saying, “It’s not the heat, it’s the humidity.”  Lower humidity allows the homeowner to raise the thermostat temperature – consequently saving energy – without a difference in how the air temperature feels.

Ask: Have you ever gotten a “clammy” or a “sticky” sensation from the air at home?

In addition to how the air feels, high relative humidity can lead to mold growth. In fact, the Centers for Disease Control and Prevention (CDC) recommends, “Keep humidity levels as low as you can—no higher than 50 percent — all day long.” A fixed speed system allows relative humidity to go as high as 60 percent, while modulating systems do not break 50 percent. Mold is harmful to the physical features of the home, in addition to human health; a modulating HVAC system prevents harmful mold growth by removing moisture from the air.

Ask: Have you ever experienced issues with mold growth in the home?

During the HVAC purchasing process, it is important to evaluate how important in-home comfort and livability are. While payback alone can be a compelling reason to purchase a modulating HVAC system, these systems also provide tangible benefits to the way you live and sleep, which for some, is priceless.