Should You Repair or Replace Your Furnace? A Downriver Homeowner’s Guide

Short answer: Repair your furnace if it’s under 12 years old, the problem is isolated, and the quote is well under half the cost of a new unit. Replace it if it’s 15+ years old, breaking down repeatedly, or the repair approaches half the cost of new. When in doubt, get an honest diagnostic — a good tech will tell you when a furnace has years left.

This is the question I get most often on service calls, and there’s no one-size answer. Here’s how I walk Downriver homeowners through it.

When Repair Is the Right Call

Repair makes sense when the furnace is fundamentally sound and the problem is isolated. Specifically:

• The unit is under 12 years old. Most furnaces last 15–20 years with maintenance. A 7-year-old furnace with a bad ignitor has a decade of life left — fix it.
• This is the first problem in years. An isolated failure on a reliable unit isn’t a pattern. It’s a part that wore out.
• The repair costs well under half of replacement. A $300 ignitor on a furnace that would cost thousands to replace is simple math.
• Energy bills are stable. If your bills haven’t been climbing, the furnace is still running efficiently. No reason to replace an efficient unit over one bad part.
• Still under warranty. Check your manufacturer warranty before deciding — if parts are covered, a repair that would cost hundreds out of pocket might cost you little or nothing.

Here’s what our repairs typically run in the Downriver area, parts and labor included:

• Service call / diagnostic: $99 ($159 after hours)
• Ignitor replacement: $200–$300
• Thermostat replacement: $200–$600
• Blower motor replacement: $600–$1,200
• Inducer motor replacement: $650–$1,500
• Control board replacement: $300–$1,000
• Gas valve replacement: $250–$600

If your quote lands in these ranges and the furnace is otherwise healthy, repair is almost always the smart money.

Some symptoms point to specific, fixable problems rather than a dying furnace. If your furnace runs but blows cold air, that’s usually a burner or airflow issue — not a death sentence. Diagnose the actual problem before jumping to replacement.

When Replacement Is the Right Call

Replacement makes sense when the furnace is telling you it’s done. The signals:

• 15+ years old with repeat breakdowns. Two service calls in one season on a 17-year-old furnace isn’t bad luck — it’s a pattern. Each repair buys less time than the last.
• Repair cost near half (or more) of new. This is the industry-standard threshold for a reason. Putting $1,500 into a furnace with a cracked heat exchanger doesn’t make sense when that money could go toward a new unit with a warranty.
• Cracked heat exchanger or CO risk. This isn’t a cost decision — it’s a safety one. A cracked exchanger can leak carbon monoxide into your home. No repair fixes a cracked exchanger economically; it’s replacement time.
• Bills climbing with the same usage. An aging furnace losing efficiency costs you every month. A new high-efficiency unit can cut heating costs noticeably — the savings offset the install cost over time.

If you’re seeing the early warning signs but aren’t sure where you land, read our guide on 7 warning signs your furnace needs repair first.

What a Furnace Replacement Costs in Downriver

Our furnace installs typically run $3,500–$6,500 in the Downriver area. Where you land in that range depends on several factors: the efficiency rating (80% vs 90%+), whether permits are needed, ductwork or venting upgrades, and extras like chimney liners. There’s no one-size price because no two houses are the same.

What affects the price: furnace size (BTU matched to your home), efficiency rating (80% vs 90%+), brand and warranty, and whether ductwork or venting needs updating. A straightforward swap of a standard-efficiency gas furnace costs less than a high-efficiency install that needs new PVC venting and condensate drainage.

Don’t let anyone sell you a bigger furnace than your house needs. Oversized units short-cycle, wear out faster, and cost more upfront — proper sizing comes from a load calculation, not a guess.

What Happens on Install Day

Here’s what to expect when we replace a furnace:

1. Old unit out. We disconnect gas, electric, and venting, then remove the old furnace. Most removals take 1–2 hours.
2. New unit set. The new furnace goes in, leveled and secured. We connect it to your existing ductwork, adapting as needed.
3. Gas, electric, venting. Gas line reconnected and leak-tested. Electrical wired to code. Venting run — PVC for high-efficiency units, metal flue for standard.
4. Thermostat and startup. Thermostat wired or replaced, system fired up, and every safety checked: gas pressure, temperature rise, CO levels.
5. Walkthrough. We show you the new thermostat, the filter location, and what maintenance it needs. Most installs are done in one day.

You’ll have heat that night. We haul the old unit away.

How to Choose the Right Furnace

• Size it right. Bigger isn’t better. A Manual J load calculation determines the correct BTU for your home’s size, insulation, and windows. This is the single most important step — and the most commonly skipped by low-bid installers.
• Efficiency. An 80% AFUE furnace is the baseline; 90%+ (condensing) units cost more upfront but cut gas bills. In Michigan winters, the payback on high efficiency is real.
• Brand and warranty. We’re a Goodman dealer — solid equipment, strong warranty, parts availability. But we’ll install what fits your home and budget, and we’ll tell you honestly if a premium brand isn’t worth the markup for your situation.
• Get it in writing. Any quote should list the furnace model, efficiency rating, warranty terms (parts AND labor), and what’s included (permits, haul-away, thermostat). If it’s vague, walk away.

The Bottom Line

If your furnace is young, healthy, and the repair is reasonable — fix it. If it’s old, breaking repeatedly, or unsafe — replace it. And if a tech ever pressures you to replace a furnace that has years left, get a second opinion.

Planning to sell your home soon? A repair that buys the furnace a few more years is often the smarter move before listing. But a dead or dying furnace will come up on inspection — don’t ignore it and hope the buyer won’t notice.

Not sure where yours lands? We diagnose honestly. If it has years left, we’ll tell you — and we’ll fix it for a fair price. Furnace repair in Downriver — $99 diagnostic. If it’s time, we’ll walk you through replacement options with real numbers, no pressure.

Call (734) 559-4688 — 24/7 for no-heat calls across Trenton, Wyandotte, Woodhaven, Riverview, Gibraltar, and all of Downriver.

Frequently Asked Questions

How do I know if my furnace is worth repairing?
Age and cost decide it. Under 12 years old with an isolated problem and a repair well under half the cost of new — repair it. Over 15 with repeat breakdowns or a repair approaching half of new — replace it.

What is the 50% rule for furnace replacement?
If a repair quote is 50% or more of the cost of a new furnace, replacement usually makes better financial sense — especially on units over 10 years old. It’s a guideline, not a law, but it’s the industry standard for a reason.

How long does a furnace installation take?
Most residential furnace replacements are done in one day — typically 4–8 hours depending on whether venting or ductwork needs updating. You’ll have heat that night.

Should I replace my furnace before it breaks?
If it’s 15+ years old and showing warning signs, proactive replacement beats an emergency no-heat call in January. You get to choose the timing, the equipment, and the installer — instead of whoever can come fastest at 2 AM.

My furnace won’t turn on at all — is it dead?
Not necessarily. Check the thermostat, filter, breaker, and gas supply first — many no-heat calls are simple fixes. Run through our 6 checks to run before you call. If those don’t bring it back, it might be time for the repair-or-replace conversation above.