5 Signs Your Furnace Won't Make It Through Another Winter

Most furnace failures happen between November and February — when demand for service is highest and response times are longest. The good news: furnaces almost always warn you before they quit. Here are 5 signs we see at ApexAir that mean your furnace is on borrowed time.

1. It's Over 15 Years Old

Gas furnaces last 15-20 years. Boilers last 20-30 (longer if cast iron). After year 15, you're playing the odds.

Signs of age beyond the model year:

• Pilot light instead of electronic ignition
• Single-stage operation (just on or off, no modulation)
• AFUE rating under 80% (look at the yellow sticker, or check the manual)

A 1998 furnace running 65% efficient costs about 40% more to heat your home than a 96% efficient modern unit. Over 5 years, that's often more than the cost of replacement.

2. Your Heating Bill Has Climbed Steadily

Compare this past winter's heating bills to 2-3 years ago, adjusted for weather. If it's gone up 15-20% with no obvious cause (no rate hikes, no extra space), the system is losing efficiency.

Internal wear (dirty burners, weakening blower motor, degraded heat exchanger) all reduce efficiency gradually. By the time you notice on the bill, the system is in the back third of its lifespan.

3. You're Hearing Strange Noises

Furnaces should run quietly. Any of these noises mean call a tech:

• Banging at startup — delayed ignition, dirty burners, or gas valve issue
• Squealing — blower motor bearing or belt failure coming
• Grinding metal — motor bearings failing
• Rumbling that continues — burner combustion issue
• Clicking with no ignition — failing igniter or flame sensor

Noises rarely fix themselves. The cheapest repair is the one done early.

4. Uneven Heating Between Rooms

If some rooms are 65°F and others are 75°F when the thermostat is set to 70°F, the system is struggling. Possible causes:

• Weakening blower motor (can't push air through full ductwork)
• Ductwork issues — leaks or undersized for the home
• Furnace undersized for the home's heat loss
• Failing zone dampers (if you have zoned heating)

Some of these are fixable; some mean it's time for a bigger furnace or a different solution (mini splits in the cold rooms, for example).

5. Yellow or Flickering Pilot Flame (Gas Systems Only)

A healthy gas flame is steady blue with a small yellow tip. Anything else is a problem:

• Mostly yellow flame: Incomplete combustion — produces carbon monoxide. Stop the system, call us, ventilate the area.
• Flickering or wavering: Drafts, dirty burners, or pressure issues
• Won't stay lit: Bad thermocouple, dirty pilot orifice, or gas pressure issue

Carbon monoxide warning: If you don't have a CO detector near your furnace, install one today. CO from cracked heat exchangers kills people in their sleep every winter in the Northeast. $15 detector. Get one.

What To Do Before Winter

If you see ANY of these signs, schedule a heating tune-up by mid-October at the latest. A proper tune-up will:

• Confirm whether the issue is repair-able or replacement territory
• Catch a cracked heat exchanger (the most safety-critical failure)
• Replace consumable parts (filter, igniter, capacitor if needed)
• Give you a written assessment of remaining life

If replacement is the right call, doing it in October beats doing it in January — installation slots are open, prices are lower, and you avoid the "my furnace died yesterday and I need it today" premium.

Suspect your furnace is on its last legs? Call (631) 555-COOL for a free assessment — we'll tell you exactly how much life is left and what your options look like.