How to Tell It's Time for a New Furnace

Furnaces tend to give you warnings before they fail completely. The trick is recognizing them. Some of the most common signs:

Age: Most furnaces are designed for 15 to 20 years of service. Past that, you're on borrowed time, even if it's still running. The efficiency drops year after year, and the cost of major repairs starts to rival the cost of replacement.

Climbing energy bills: If your gas usage is creeping up but your habits haven't changed, an aging furnace is often the culprit. Worn parts, dirty burners, and degraded heat exchangers all eat into efficiency, and Con Edison gas rates don't make that any easier to absorb.

Uneven heating: When some rooms feel toasty while others stay cold, your furnace might not have the capacity it once did. Could also be ductwork issues, but worth investigating either way.

Strange sounds: Banging on startup, rumbling, squealing, or rattling are all signs something is wearing out. Furnaces should run quietly. Anything else is a clue.

Yellow flame instead of blue: A yellow or flickering flame can mean incomplete combustion, which produces carbon monoxide. This is a safety issue, not a "we'll get to it next month" issue.

Frequent repairs: When you're calling for service multiple times a season, the math usually favors replacement. A common rule: if a single repair costs more than a third of a new furnace, it's time to start shopping.

If you're dealing with two or three of these at once, replacement is almost certainly the right call. Globe Mechanical & Electrical offers free in-home assessments where we'll tell you straight whether a repair makes sense or whether you're better off putting that money toward a new system.

Why Sizing Matters More Than You Think

Here's the single most common mistake in furnace installation: getting the size wrong. And it goes wrong in both directions.

Too small, and the furnace runs constantly trying to keep up, never quite getting there on the coldest nights. And Yonkers does see real cold spells. Too big, and it short-cycles, blasting hot air for ten minutes and shutting off, leaving uneven temperatures and excessive wear on the equipment. Both scenarios shorten the life of the furnace and waste fuel.



The right way to size a furnace is a Manual J load calculation, which factors in your home's square footage, insulation levels, window quality, ceiling heights, climate zone, and air leakage. Anyone who quotes you a furnace based on "what was here before" or "your square footage" is skipping the most important part of the job.

Globe Mechanical & Electrical does real load calculations on every install. It takes a little longer up front, but it's the difference between a furnace that runs perfectly for two decades and one that's a disappointment from week one.

What a Quality Furnace Installation Includes

A thorough furnace installation has more steps than most homeowners realize. Here's what should happen.

The old furnace gets removed safely, including proper handling of any refrigerant in the AC coil if applicable, and disposal according to local regulations. In older Yonkers homes, this sometimes means dealing with asbestos around old ductwork, which has to be handled by certified professionals.

The new furnace is set in place and connected to the existing ductwork. If the ductwork is undersized, leaky, or poorly designed, this is the time to address it. A premium furnace connected to bad ducts is money wasted.

Gas line connections (or oil/electric, depending on fuel) get made and pressure-tested for leaks. The flue gets installed with proper venting, which for high-efficiency condensing furnaces means PVC venting and a condensate drain.

Electrical connections are completed, the thermostat is wired or replaced, and the system is fired up for testing. Combustion analysis confirms the furnace is burning cleanly. Airflow is measured and balanced. The thermostat is calibrated.

Finally, the installer walks you through how the system works, how to change filters, how to use the thermostat, and what to watch for. Manufacturer warranty registration gets handled, and any City of Yonkers permit inspections are scheduled.