Quick answer: Repair a furnace that is under about 15 years old, has a repair cost well under half the price of a new one, and has a sound heat exchanger. Replace it when the heat exchanger is cracked, when the repair runs past half of a new system, or when you are on your second or third repair in as many years. In Abilene, the short heating season buys an older furnace more time than it would up north — but it does not make a cracked heat exchanger safe.
Nobody wants to be told to replace a furnace. We get that. So when Tom or one of the crew is standing in your utility closet with a bad diagnosis, the honest answer is usually not a sales pitch — it is arithmetic, plus one safety question that overrides everything else.
Start with the West Texas wrinkle
A furnace in Abilene does not work anywhere near as hard as one in Amarillo or Denver. We run heat in real earnest for maybe two or three months, and plenty of winter days here never call for it at all. National guidance that says a furnace lasts 15 to 20 years is written for houses that heat for six months. On heating hours alone, ours can outlast that.
Here is the part most homeowners do not know: the blower inside your furnace is the same blower that moves your air conditioning all summer. So the furnace cabinet does get worked hard in Abilene — just not by the burners. It is common here to see a 20-year-old furnace with a nearly new-looking burner assembly and a blower motor, capacitor, and control board that have 20 brutal summers on them. When we talk about the life left in your furnace, that is what we are actually looking at.
The age question
Rough brackets, assuming the unit has been serviced:
- Under 10 years — repair, almost always. Parts are available, the cabinet has plenty of life left, and a major component may still be under manufacturer warranty. Check that before you pay for anything.
- 10 to 15 years — usually repair, but start paying attention. This is when igniters, inducer motors, gas valves, and control boards begin to fail. One repair is normal. A pattern is information.
- 15 to 20 years — it depends entirely on what broke and what it costs. This is where the arithmetic below earns its keep.
- Over 20 years — replacement is usually the better money, and it is worth planning rather than waiting for a failure in January. An old furnace rarely fails at a convenient time.
Then do the arithmetic
The rule of thumb the trade uses, and the one we use: if the repair costs more than half of a new furnace, put the money toward the new furnace. A $400 igniter and inducer job on a 12-year-old unit is easy money. A $1,900 repair on an 18-year-old furnace is not — you would be spending a large share of a new system to keep an old one limping.
Add up what you have already spent, too. If the furnace has cost you two or three repairs in the last couple of winters, the total matters more than the next invoice. That pattern rarely reverses.
A cracked heat exchanger is not a repair-or-replace judgment call. The heat exchanger is the metal wall that keeps combustion gases — carbon monoxide among them — out of the air blowing through your house. When it cracks, that separation is gone. Carbon monoxide is colorless and odorless, so you will not smell the problem.
Technically a heat exchanger can be swapped, and on a furnace still inside its warranty that is sometimes worth doing. In practice the job takes most of a day of skilled labor on a unit that is usually old enough that the rest of it is aging too, so replacement is nearly always the better call. Either way the furnace gets shut down until it is fixed, and we will tell you that straight. Keep a working CO detector on every floor and near the bedrooms regardless of how new your system is.
Signs that point to replace
- A cracked heat exchanger — see above.
- Repair quote past half the cost of new, especially on a furnace over 15.
- Two or more repairs in two years. You are funding a system that has started to come apart.
- Rooms that never get comfortable and a furnace that runs constantly. Sometimes that is ductwork rather than the furnace, which is worth checking before you buy anything.
- Rising gas bills with no change in how you live or what the weather did.
- Obsolete parts. On some older units the part simply is not made anymore, and a used board is not a fix we will stand behind.
- Your AC is the same age. The furnace and the outdoor unit share the blower and the duct system, and replacing both together costs less than two separate jobs a few years apart — and gets you a matched system that actually performs the way the rating says.
Signs that point to repair
- One clear failed part on a furnace under 15 — igniter, flame sensor, capacitor, pressure switch, thermostat.
- Still under warranty. Many manufacturers cover the heat exchanger for a long stretch and other parts for 10 years, provided the unit has been registered and serviced. Let us look it up before you decide.
- Heat that has been steady and bills that have not crept up. A single bad part on an otherwise healthy furnace is just a repair.
- You are moving soon. Fair reason to fix rather than buy, and we will say so.
One thing worth knowing before 2028
Federal efficiency rules are changing. Residential gas furnaces built after December 18, 2028 will have to hit 95 percent AFUE, which means the 80 percent non-condensing furnaces most Abilene homes have will no longer be manufactured. The rule survived a court challenge in late 2025, so plan on it holding. It does not force anyone to replace a working furnace, and it does not affect repairs — but if you are choosing between efficiency levels on a new install, that is useful context.
Now the honest local version: because our heating season is short, the fuel savings from a 95 percent furnace pay back slower here than the brochures assume. Somebody in Minnesota recoups that upgrade quickly. In Abilene it takes longer, and the higher-efficiency furnace also needs different venting, which adds to the install. It is a genuinely good piece of equipment and there are good reasons to choose it. We would rather show you the real numbers for your house than push you either direction.
What we do when we come out
We diagnose the actual failure, tell you what the repair costs, and tell you what a replacement costs, and then you decide. No hovering, no one-day-only pricing. If replacement is the better call we will explain exactly why, and if the furnace has years left we will say that too — we would rather service it for another decade than sell you something you do not need.
If cost is the sticking point, we offer financing through First Financial Bank, who set all the rates and terms. And if you would rather stay ahead of this altogether, a H.A.V.E.N. maintenance plan puts eyes on your heating and cooling every year, which is how furnaces reach the long end of their life instead of the short end.
We have been sizing, servicing, and replacing furnaces in the Big Country since 1976. Call or text (325) 692-3645 and we will come take a look at yours. More on what we cover on our heating and furnace service page.
Written by the Hawkins Air Conditioning team — family-run in Abilene since 1976. Questions? Call or text (325) 692-3645.
