What HVAC pros actually do (and when to dispatch one)
HVAC contractors install, service, and repair the systems that heat, cool, ventilate, and clean the air in your home — central AC, furnaces, heat pumps, mini-splits, boilers, ductwork, ERVs and HRVs, humidifiers, and indoor air quality equipment. The single highest-leverage thing a homeowner can do is book a $90–$160 maintenance tune-up twice a year (spring for cooling, fall for heating). Most catastrophic HVAC failures are visible six months in advance to a tech with the right gauges.
Call an HVAC pro when your system runs constantly without holding temperature, you hear new noises (squealing, grinding, banging), a room won't heat or cool no matter the thermostat setting, the system short-cycles (turns on and off every few minutes), the outdoor unit freezes over in summer, or your energy bill jumps without a change in habits. If your system is more than 12 years old, ask any contractor you talk with to price both repair and replacement — modern heat pumps are 30–60% more efficient than 2010-era central AC, and federal and state rebates frequently knock $2,000–$8,000 off the install.
What a typical HVAC job costs
Indicative from Home Trades Nearby quotes: seasonal tune-up $90–$160; capacitor or contactor replacement $200–$450; refrigerant leak diagnosis and recharge $400–$1,200; full central AC condenser swap $4,500–$8,500; complete heat pump system with air handler $9,000–$18,000 before rebates; new ductwork in a 2,000 sq ft home $4,000–$10,000. Verify any quote includes a Manual J load calculation — undersized and oversized systems both fail early.