Yes, and we try to make it a numbers conversation rather than a judgment call. Age, repair cost, efficiency, and safety each point somewhere, and when they disagree we explain the tradeoff instead of just recommending the bigger invoice.

Start With Age

Gas furnaces generally last fifteen to twenty years. Where yours falls in that range frames everything else.

Under ten years, repair is almost always right. Components fail on young equipment, and the rest of the system has plenty of life left. Between ten and fifteen, it depends on the repair cost and the condition of the major components. Past fifteen, every repair should be weighed against how many more seasons you realistically get.

Furnaces in the Hill Country often outlast their national average, simply because heating season here is short. A twenty-year-old furnace in Fredericksburg has far fewer runtime hours on it than the same unit in Colorado, and that genuinely matters.

The Repair Cost Test

A useful rule of thumb: multiply the repair cost by the age of the furnace. If the result exceeds the cost of a new system, replacement is usually the better decision.

A second, simpler version: if a repair costs more than a third of replacement on a system past two-thirds of its expected life, you are probably spending good money to postpone an inevitable purchase.

Neither rule is absolute. They are a starting point for a conversation about how long you plan to stay in the house and how much risk you are willing to carry through a cold snap.

When It Is Not a Choice

Two findings end the discussion.

A cracked heat exchanger means replacement. A crack allows combustion gases, including carbon monoxide, to mix with the air circulating through your house. The part itself is expensive enough on most units that repair rarely makes sense, and running the furnace with a known crack is not an option we will leave open. If we find one, we red-tag the unit and explain exactly what we saw.

The second is a furnace that has become unsafe in other ways — failed venting that cannot be corrected, or a control system with no available parts. Obsolescence is real; support for older models does end.

Repairs Worth Making

Plenty of furnace failures are straightforward and worth fixing regardless of age. Igniters, flame sensors, pressure switches, blower capacitors, limit switches, and control boards are all normal wear items. A flame sensor that needs cleaning is not a reason to replace a furnace, and any company that tells you otherwise is selling rather than diagnosing.

Regular furnace maintenance catches most of these while they are cheap, which is the entire argument for doing it.

What Replacement Buys You

If replacement is the direction, the upside is more than reliability. Modern furnaces run at substantially higher AFUE than equipment from the nineties, and variable-speed blowers improve comfort year-round — including in cooling season, since the same blower moves your air conditioning.

It is also the moment to reconsider the system type. Given our mild winters and long cooling season, a heat pump is worth evaluating seriously, since it handles both jobs efficiently. A hybrid fuel system pairs a heat pump with a gas furnace and switches automatically, which suits homes that already have gas service.

How We Evaluate

An honest assessment means inspecting the heat exchanger, testing combustion, checking the blower and controls, measuring temperature rise, reviewing your repair history, and looking at the ductwork that feeds it.

Then you get both numbers — the repair price and the replacement price — with the reasoning behind each. Sometimes the answer is repair now and plan to replace next year, which is a legitimate strategy when a system will get you through one more season.

Deciding Before It Fails

The worst time to make this decision is during a freeze with no heat in the house. If your furnace is past fifteen and gave you trouble last winter, an evaluation in the fall costs nothing and removes the pressure.

A furnace repair and a furnace replacement are both on the table until we look. Financing is available.

We serve Fredericksburg, Kerrville, Boerne, Comfort, and the surrounding Hill Country. Contact 72 Degrees or call (830) 240-1835.