Heating and air conditioning is one half of HVAC. The other half is ventilation and indoor air quality. Simply controlling the temperature of the air is not enough to give you a complete portrait of home comfort.
Normally, you would fix your air quality issues by installing humidity controllers or air purifiers. These devices directly improve your comfort by balancing moisture in the air and by removing germs.
However, there is a very serious part of indoor air quality that often goes understated: radon exposure. If your home has unsafe levels of radon, you’ll want to have it addressed immediately.