PUTNAM COUNTY, W.Va. (WSAZ) - With heat index values climbing above 100 degrees, air conditioners across the Tri-State are running around the clock. HVAC professionals say a few simple maintenance steps can keep systems running efficiently and help homeowners avoid expensive repairs. One of the most common problems this time of year, according to heating and cooling professionals, is a dirty air filter. A clogged filter restricts airflow and forces the unit to work harder to cool a home.