When should I repair vs. replace my furnace or air conditioner?

A common rule of thumb is the "5,000 rule": multiply the age of the unit (in years) by the repair cost in dollars. If the result exceeds $5,000, replacement is usually the better investment. For a 15-year-old furnace with a $400 heat exchanger repair, 15 × 400 = $6,000 — exceeding the threshold, suggesting replacement. Beyond this formula, replace rather than repair when: the heat exchanger is cracked (a safety risk that allows carbon monoxide to enter the living space), the compressor in a central AC has failed (compressor replacement typically costs $1,200–$2,500, often making replacement more economical), the system requires refrigerant that is being phased out (R-22/Freon was phased out in 2020 and replacement refrigerant costs have risen sharply), or the equipment is more than 15 years old and repairs have been recurring. Newer equipment is significantly more efficient — a 96% AFUE furnace vs. a 70% AFUE unit from 1995 can reduce heating costs by 25–30%.

How much does a new furnace or AC cost?

A new gas furnace installed in a home typically costs $2,500–$6,000, including equipment and labor. High-efficiency 95%+ AFUE models (recommended in cold climates) run $3,500–$6,500. A central air conditioner replacement costs $3,000–$6,000 installed for a standard 2–4 ton unit. Replacing both the furnace and AC together often costs $6,000–$12,000 and is frequently more cost-effective than replacing them separately. Heat pump systems (which handle both heating and cooling) cost $5,000–$14,000 installed, and utility rebates from your local energy provider can reduce that cost by $500–$1,500 for qualifying high-efficiency models. Ductwork replacement or sealing adds $800–$3,000. Get at least two bids that specify the equipment brand, model, SEER (cooling efficiency), AFUE (heating efficiency), and warranty coverage so you can compare fairly.

How long do HVAC systems last?

Gas furnaces typically last 15–25 years with regular annual maintenance. Central air conditioners last 12–18 years on average. Heat pumps last 10–15 years. Water heaters—often maintained by HVAC contractors—last 8–12 years for tank models and 15–20 years for tankless. In cold climates, furnaces run for months of sustained cold, and air conditioners work hard during hot, humid summers. Annual furnace tune-ups (ideally in fall before heating season) and annual AC tune-ups (in spring before cooling season) extend system life, improve efficiency, and help catch problems before they become expensive failures. Most HVAC contractors offer maintenance plans or service agreements that include priority scheduling for emergencies, which is valuable when a furnace fails during a winter cold snap.

How do I find HVAC contractors near me?

Search EdgeLocal for "HVAC," "heating," "cooling," or "air conditioning" with your zip code to find local heating and cooling contractors. HVAC stands for heating, ventilation, and air conditioning—contractors in this field install, service, and repair furnaces, air conditioners, heat pumps, boilers, ductwork, and ventilation systems. HVAC technicians working on refrigerants are required to hold EPA Section 608 certification. Contractors installing or modifying mechanical systems must be licensed through their state's mechanical systems licensing board. When hiring, ask for certification numbers and proof of current insurance. For new HVAC system installation, get two to three bids that each specify the equipment brand, model, SEER rating (for cooling) or AFUE rating (for heating), warranty terms, and whether the contractor handles permit filing. For service and repair calls, ask about diagnostic fees upfront. EdgeLocal ratings and reviews help you compare local HVAC contractors before calling.

What does an HVAC tune-up include and how often do I need one?

A standard HVAC tune-up typically includes: inspecting and cleaning the heat exchanger or evaporator coil, checking refrigerant levels, cleaning or replacing the air filter, testing electrical connections and safety controls, lubricating moving parts, checking the condensate drain, testing thermostat operation, inspecting ductwork connections near the unit, and measuring airflow and temperature differential. For a gas furnace, the technician also inspects the heat exchanger for cracks (which can allow carbon monoxide to enter living spaces). Most HVAC manufacturers recommend annual maintenance to maintain warranty coverage. The standard cadence is a furnace tune-up in fall before heating season and an AC tune-up in spring before cooling season. Cost: $75–175 per visit. Many contractors offer maintenance plans at $150–300 per year covering both visits plus priority scheduling.

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128 Plumbing, Heating, Cooling & Electric

BOSTON · MA

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