Replace a 15 year old furnace before it quits, or run it until it dies?

: I'd get a second quote before deciding anything. When I bought my place in 2019 the furnace was a 2006 Rheem and the selling inspection said it was fine. First company that came out for a tune-up told me the heat exchanger was shot and quoted me a fortune, real doom and gloom. Second company found nothing wrong, just a dirty flame sensor. That thing ran four more winters before I finally replaced it on my own schedule in the off-season and got a fair price because the crew wasn't slammed. So my take is that a 2010 unit with no history isn't automatically a five grand problem. Get the tune-up this fall, ask them to show you the exchanger with a camera if they claim it's cracked, and put the replacement money in a savings account in the meantime. If it dies in January you've got the cash ready and you can wait a few days for a normal quote instead of taking the first number. That's what I did and the difference between an emergency install and a planned one was real money.

I'm on the replace-early side of this. We bought a house with a mid-2000s Carrier that ran fine, and I went back and forth for two seasons before just doing it. Best decision, not because it died but because of how I got to do it.

I scheduled the swap in September, got three quotes at my leisure, and picked a local shop instead of whoever could come fastest. The crew took a full day, did the job right, and I paid a normal rate. My neighbor waited for a January failure and ended up with an emergency install during a snowstorm, whatever unit the supply house happened to have in stock that week.

The other thing I noticed was the gas bill. The old unit was prolly somewhere around 80 percent efficient, and the new one is in the mid-90s. My winter costs dropped enough that I could point to the difference on my statements. Not enough to pay for the furnace overnight, but real money every cold month.

A 15 year old unit with no maintanence history and a filter slot full of dust is alredy living on borrowed time, even if it fires right now. If it were mine I'd shop quotes this fall while companies aren't slammed, and spend the winter enjoying heat instead of listening for the moment it quits.

Been at this since the days of standing pilots and cast iron burners that never quit. Those old clunkers ran thirty, forty years with nothing but a pilot fix and a good brushing. A furnace that age is still a teenager next to what I worked on, so no panic here. One habit from way back that still works: have your tech leave you a spare hot surface igniter, costs almost nothing, and keep it in the drawer. First hard freeze every winter that's the part that quits, not the big money stuff. Used to get three no-heat calls before lunch on the first cold Monday of the season. Cheap insurance against a dead weekend in January.

Agree with getting the second oppinion. Same story here, bought a house with a late-90s furnace and the first tech said it was on its last legs. Ran another six years, and when I finally swapped it I did it in late August. The installer wasn't rushed at all, spent extra time sealing the connections to the old ductwork and walked me through the new thermostat. Try to book yours for the shoulder season if you go that route.

Total beginner here, still figuring out what a tune up even involves. When the tech comes this fall, is there anything I should ask them to actually check, or do they just do the whole thing by default? I worry I'll stand there nodding and have no clue if they looked at the important parts. Also does the yearly checkup cost much? Trying to figure out what I'd be signing up for before I call anyone.

That packed filter slot is the detail I'd zero in on. A furnace choked like that runs hot, and years of running hot is what stresses an exchanger in the first place. I do fall tune-ups every season and maybe one in ten units that age actually turns out to need anything beyond a good cleaning, but a neglected one is exactly the type I look at harder. When the tech comes, ask them to check temperature rise across the furnace against the rating plate and watch whether it short cycles. Also, a combustion test tells you more about an exchanger than eyeballing it does, so ask if they do one.