FREQUENTLY ASKED QUESTIONS

Perfect comfort is something we want you to experience long after you’ve purchased your Lennox^® product. That’s why we offer a collection of resources that make it as easy as possible for you to get the answers and support you need.

How hard is my system working?

Your thermostat maintains comfort by automatically adjusting how hard your HVAC system works and for how long it operates. Your monthly summary report displays the average demand for each component in your system.

Demand is a number from 0 - 100%, where 100% is the maximum heating or cooling your system can provide. For example, a system running at 50% cooling demand is delivering half of its maximum cooling capacity. Demand provides better insight than runtime alone because it factors in what level of heating or cooling the system was operating. This is important for multistage and variable capacity systems that use multiple levels of heating or cooling. Using lower levels of heating or cooling can result in longer runtimes, but it is more efficient. Heating demand can usually increase as the outdoor temperature drops. As you transition from fall into winter, you will typically see your heating demand increase. Similarly, in the spring heating demand will typically decrease as the weather warms up. Your report includes the average outdoor temperature for each month, enabling you to compare your change in heating demand to the change in temperature.

Cooling demand will typically increase as the outdoor temperature increases. Cooling demand will usually be the highest in the peak of Summer and drop off as temperatures decrease.

Single Stage
Single stage systems have only one operating capacity, on at 100%. Therefore, the thermostat simply adjusts demand by changing runtime.

Two-Stage
Two-stage systems have two operating stages. The thermostat will first attempt to maintain comfort by operating only the lower stage. When the system cannot maintain comfort with the lower stage, it will begin to operate the higher stage.

Variable Capacity
Variable capacity systems continuously adjust the heating or cooling capacity from its minimum to its maximum capacity. The thermostat will maintain comfort by continuously adjusting the capacity of the system.

Electric Heat and Fan Demand calculations always assumes 100% capacity when on.