5 Signs You Need a New HVAC System (And What Replacement Costs)

Is It Time to Replace Your HVAC System?

Your heating and cooling system works hard to keep your home comfortable year-round, but no HVAC system lasts forever. The average air conditioner lasts 15-20 years, while furnaces typically have a lifespan of 20-30 years. Knowing when to repair versus replace your system can save you thousands of dollars and prevent an unexpected breakdown during extreme weather.

Here are five clear signs that your HVAC system may be nearing the end of its useful life and it is time to start planning for a replacement.

Sign 1: Your System Is Over 15 Years Old

Age is one of the most reliable indicators that replacement is approaching. If your air conditioner is over 15 years old or your furnace is over 20 years old, it is operating with outdated technology that is significantly less efficient than modern systems. Today's HVAC systems are 30-50% more energy efficient than models from 15 years ago, which means a new system could substantially reduce your monthly utility bills.

Even if your older system is still running, it likely uses R-22 refrigerant (Freon), which has been phased out and is now extremely expensive to replace. If your system needs a refrigerant charge, this alone could cost $150-$300 per pound compared to $10-$20 per pound for the R-410A refrigerant used in modern systems.

Sign 2: Rising Energy Bills

If your heating and cooling bills have been steadily increasing despite no change in usage patterns, your HVAC system is losing efficiency. As components wear out, the system has to work harder and run longer to maintain the same temperature, consuming more energy in the process. Compare your bills from the last three years; if they have increased by more than 15-20% without rate changes, your system's declining efficiency is likely the culprit.

Sign 3: Frequent and Expensive Repairs

A good rule of thumb is the 50% rule: if a repair costs more than 50% of the value of your system, replacement is the smarter financial decision. Similarly, if you have needed multiple repairs in the past two years, those costs are adding up and would be better invested in a new, warranty-covered system.

Common expensive repairs on aging systems include compressor replacement ($1,500-$3,000), evaporator coil replacement ($1,000-$2,500), and heat exchanger replacement ($1,500-$3,500). If your technician recommends any of these on an older system, it is generally time to replace rather than repair.

Sign 4: Uneven Temperatures and Poor Comfort

If some rooms in your home are too hot while others are too cold, or if your system runs constantly without reaching the set temperature, the equipment may be failing. Other comfort-related warning signs include excessive humidity in summer, dry air in winter, and dust buildup despite regular filter changes. These issues often indicate that the system can no longer adequately condition your home.

Sign 5: Unusual Noises or Odors

Healthy HVAC systems operate relatively quietly. If you are hearing banging, squealing, grinding, or rattling sounds, components inside the unit are failing. Strange odors are also concerning: a burning smell could indicate electrical problems, a musty smell suggests mold in the ductwork or unit, and a rotten egg smell could signal a dangerous gas leak that requires immediate attention.

What Does HVAC Replacement Cost?

• Central air conditioner: $4,000-$8,000 installed for standard efficiency, $8,000-$15,000 for high-efficiency models
• Gas furnace: $3,000-$6,000 installed for standard efficiency, $6,000-$12,000 for high-efficiency models
• Heat pump system: $5,000-$10,000 installed, with higher-end models reaching $15,000
• Complete HVAC system (AC + furnace): $7,000-$15,000 for mid-range, $15,000-$25,000 for premium
• Ductless mini-split: $3,000-$5,000 per zone installed

Find HVAC Contractors Near You

If you are experiencing any of these signs, connect with trusted HVAC contractors through FindMyContractor. Get free estimates from licensed, reviewed professionals in your area and make an informed decision about your home's comfort system.