We recommend maintenance appointments for your HVAC system once a year for heat and once a year for air conditioning to keep your system in best shape. Maintenance appointments with Gray technicians make sure your motor, housing, coils, filters, and housing are all functioning to their best abilities. Symptoms of an HVAC system in need of an update are constant repairs and an inability to heat and cool your home properly. An HVAC system 15 years or older can't operate as efficiently and may cost you more overall.