Is It Cheaper To Repair Or Replace A Furnace?

Salt Lake City winters arrive fast and stay cold. When a furnace starts sputtering in January, the question becomes urgent: fix the old unit or invest in a new one? The right choice depends on age, repair cost, efficiency, safety, and how long the home will be kept. This article breaks down the decision with clear rules of thumb, local pricing context, and practical examples from homes across Salt Lake City, UT.

Start with the 50% rule and the $5,000 rule

Technicians in the field use two quick checks to frame the decision. First, if a single repair approaches 50% of the price of a new furnace, replacement usually makes more sense. Second, multiply the furnace age by the repair cost. If that number is higher than $5,000 to $6,000, it is often smarter to replace. A 14-year-old unit with a $600 repair equals 8,400 using this rule, which points to replacement. These shortcuts do not replace a full diagnosis, but they prevent sinking money into a system that is near the end of its service life.

Typical furnace lifespan in Salt Lake City

Most gas furnaces last 15 to 20 years. Units in Sugar House and Millcreek tend to run longer because homeowners often service them before the heating season. Systems in older Rose Park or Glendale homes that have dated ductwork see more wear and may fail earlier. Altitude is not the main issue; dust, filter neglect, and oversized or undersized equipment cause more problems. If the furnace is past 15 years and needs a major part, replacement starts to look practical.

What common repairs cost locally

Pricing varies by brand and access, but real ranges help set expectations. In the Salt Lake Valley, a flame sensor cleaning or replacement often falls between $120 and $250. An igniter typically costs $200 to $350 installed. Pressure switches can land between $250 and $450. Blower motors vary widely: a standard PSC motor may be $400 to $700 installed, while an ECM variable-speed motor can run $800 to $1,600. A control board might be $450 to $900. A heat exchanger, which is the furnace’s core, can exceed $1,500 with labor and may push the decision toward replacement, especially after year 12.

These numbers matter when comparing to a new, properly sized furnace. Many Salt Lake City homeowners spend $5,500 to $9,500 for a standard 80% to 96% AFUE gas furnace with professional installation, code upgrades, and a new thermostat. Two-stage and variable-speed systems, common in Holladay and the Avenues for comfort and noise control, sit on the higher end of that range.

Efficiency and gas bills through winter

Energy efficiency is more than a rating on a label; it shows up in Questar gas bills from November through March. An 80% AFUE furnace wastes 20% of the fuel as flue heat. A 95% AFUE unit wastes only 5%. In a typical Salt Lake City home using 600 to 900 therms for heating per season, upgrading from 80% to 95% can save roughly 90 to 135 therms. At recent Utah natural gas rates, that can mean around $70 to $150 in annual savings, depending on usage and weather. If the current furnace still has 5 years of reliable life, those savings may not offset the cost of replacement. If it is unreliable or inefficient and you plan to stay in the home, the math begins to favor a new unit.

Comfort and noise are part of the value

Homeowners often tolerate a few chilly rooms in Marmalade or a loud start-up in Liberty Wells until a failure forces a decision. Newer two-stage or modulating furnaces deliver more even heat and quieter operation. They help with high-low temperature swings in homes with long runs to basements or additions. If the family is sensitive to drafts or noise during overnight cycles, this comfort gain becomes part of the replacement case. It is hard to put a number on better sleep, but it shows up in fewer service calls and fewer thermostat battles.

Safety cannot be a maybe

Any sign of a cracked heat exchanger changes the conversation. Carbon monoxide risk is non-negotiable. If a licensed technician finds a confirmed crack or detects CO issues, the furnace should be shut down and replaced. Repairs that claim to “patch” exchanger issues are not recommended. In these cases, replacement is not about saving money; it is about safe heat.

How age and part availability sway the decision

After year 12, part failures often cluster. First the igniter, then the inducer motor, then a control board. Each repair alone might be reasonable, but together they exceed the value of the remaining life. Parts for certain older models found in East Bench and Cottonwood Heights can be hard to source during peak season, which leads to long waits. If a repair requires a specialty board or inducer with a multi-day lead time in a cold spell, many owners choose replacement to avoid space heaters and risk of frozen pipes.

A simple way to compare your options

Use one brief list to clarify the path.

Repair makes sense if the furnace is under 10 years old, the repair is under $600, the system is safe, and heating bills seem normal. Replace makes sense if the unit is 15 years or older, the repair quote is over $1,200, the heat exchanger is questionable, or rooms heat unevenly and gas bills are rising.

This list does not replace a diagnosis, but it helps steer the conversation.

Real examples from SLC homes

A family in the Avenues with a 9-year-old 92% AFUE furnace faced a failed igniter and dirty flame sensor. The repair cost was under $300, and the system had been reliable. Repair was the clear choice. A homeowner in Kearns had a 17-year-old 80% furnace with a failing inducer motor and noisy blower. The combined repair quotes were near $1,400. Ducts were fine, but winter gas bills had crept up 20% over three years. Replacement with a 96% two-stage furnace solved the noise and dropped bills the next season.

Hidden upgrade costs that are worth planning for

Permits and code updates are part of any responsible replacement in Salt Lake City. Expect flue adjustments for high-efficiency units, a condensation drain, and in some cases a new gas shutoff or sediment trap. Homes with older mercury thermostats often benefit from a modern programmable or smart thermostat that handles staging. If the return air is undersized, addressing ductwork at the same time improves airflow and reduces noise. Bundling these fixes with the new furnace avoids rework and service calls later.

Timing matters in Salt Lake County

Fall is the best window for either furnace repair in Salt Lake City or a planned replacement. Parts are easier to source, and crews can take the time to set up, test static pressure, and balance airflow. Emergency work during a January deep freeze can still be done, but options narrow, and temporary solutions sometimes cost more in the long run. If the system is limping through October with short cycling or burner lockouts, acting before a cold snap protects the home and the budget.

Warranties and the real cost of waiting

A quality repair includes a parts warranty and often a labor warranty from the contractor. Manufacturer warranties on new furnaces in this area commonly offer 10 years on parts and 20 years to lifetime on heat exchangers, depending on the brand and registration. Compare that coverage to the likely repair cadence on an older unit. A single mid-winter ECM motor replacement can wipe out the savings of waiting one more season to replace. If the furnace is already past the typical lifespan, the risk tilt favors a new install with predictable coverage.

How Western Heating, Air & Plumbing approaches the decision

A technician starts with a full safety and performance check: combustion analysis, static pressure reading, flue inspection, flame signal, and temperature rise. That data shows if the furnace is under stress or if a simple repair will restore reliable heat. The team then compares the repair estimate to replacement options sized for the home’s square footage, duct design, and altitude considerations. No guesswork, no upsell. Just clear numbers and a recommendation based on the home’s goals, whether that is lowest upfront cost, lowest long-term cost, or better comfort.

Quick homeowner checklist before deciding

Note the furnace age from the data plate or service records. Gather gas bills from last winter to spot any trend. Listen for new noises at start-up and shutdown. Check how many rooms feel under-heated or overly warm. Replace the filter and confirm airflow before calling.

Bring this information to the appointment and the technician can give a sharper answer on whether to repair or replace.

Ready for clear answers and fast heat?

For straight advice on furnace repair Salt Lake City homeowners can trust, Western Heating, Air & Plumbing is available for same-day service in Downtown, Sugar House, Rose Park, Millcreek, HVAC repair service Holladay, and nearby neighborhoods. Whether it is a quick igniter swap or a right-sized high-efficiency furnace, the team will show the numbers, explain the trade-offs, and get the heat back on furnace maintenance Salt Lake City westernheatingair.com safely. Call or schedule online to book a diagnostic today.