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Furnace Replacement in Commerce City, CO
Commerce City winters don't negotiate, and a tired furnace shows it fast. This guide covers what furnace replacement costs here in 2026, when a repair is still the right call, and what to expect from the licensed local installers we connect you with.
Updated October 2026 · Written from first-hand field experience in the north Denver metro · Prices verified against 2026 Denver-metro quotes
Get a straight answer on your furnace
Talk to a licensed local installer in Commerce City. Free second opinions on replacement quotes — no pressure, no obligation.
Typical response time: under 15 minutes, 7am–7pm daily.
Is it the furnace, or something simpler?
Before you price a replacement, rule out the cheap fixes. In our experience these cause most "furnace trouble" calls in Commerce City:
- Dead thermostat batteries or a tripped breaker — check these first, seriously.
- Clogged filter choking airflow — a $15 filter fixes the "runs but barely heats" complaint more often than people expect.
- Failed ignitor or flame sensor — a $200–$400 repair, not a $5,000 replacement.
Call now, don't wait: smell of gas, carbon monoxide alarm, or water pooling under the furnace. Those are same-day problems.
Repair or replace? The honest fork
Repair it
Furnace is under 12 years old, the repair is under ~$800, and your heating bills haven't crept up. A good tech gets you 3–5 more years.
Replace it
15+ years old, second major repair in two years, cracked heat exchanger, or rooms that never get warm. At that point you're paying for heat you don't get.
Rule of thumb we stand behind: if the repair costs more than about a third of a new system and the furnace is past 12 years, replacement usually wins on math alone.
What furnace replacement costs in Commerce City (2026)
Quotes in Commerce City swing wide: a 1960s–80s ranch near the older neighborhoods may need duct or electrical updates, while a newer build near Reunion is usually a straightforward swap. The house's age tells you most of the story.
What moves you up or down inside that range:
- Efficiency rating — 80% AFUE vs 96%+ AFUE is the biggest price jump — and the biggest gas-bill difference.
- Sizing — Most Denver-metro homes land between 60k–100k BTU; oversizing wastes money every month.
- Ductwork condition — Leaky or undersized ducts can add $1,000–$3,000 if they need work.
- Venting and permits — High-efficiency units need PVC venting; permit and inspection are included in reputable quotes.
Commerce City has two furnace stories. In the older core — the post-war ranches near the original townsite — original and second-generation 80% furnaces are aging out, often in tight closets or low basements where venting clearances matter. In Reunion and the north-side developments, builder-grade furnaces from the 2000s are reaching the age where control boards and blower motors start failing in clusters. Either way, altitude is the quiet factor: at this elevation the input has to be derated properly, or the new furnace short-cycles from day one.
What happens when you call
- We answer and listen. You tell us the symptoms, the equipment's age, and your address. We confirm a licensed installer serves Commerce City.
- A licensed local tech arrives. They diagnose, give you repair and replacement options in writing, and answer questions on the spot.
- You contract directly with the installer. The estimate, the work, and the warranty are between you and the licensed company doing the work — not with this guide.
- The installer warranties the work. Equipment warranty from the manufacturer, labor warranty from the installer, both in writing.
How this site works: Mile High HVAC Guide is an independent publisher. We don't install HVAC equipment. When you request help, we connect you with a licensed local contractor and may receive a referral fee from them. It never changes what you pay.
Questions Commerce City homeowners actually ask
How long does a furnace replacement take?
Most straightforward swaps are one day — crew arrives in the morning, you're heating by evening. If ductwork or venting needs changes, plan for two.
What size furnace does my house need?
It depends on square footage, insulation, and windows — not on what was there before. A proper installer runs a Manual J load calculation. "Same size as the old one" without measuring is a red flag.
Do I need a permit for this in Commerce City?
Yes — the City of Commerce City requires a mechanical permit and inspection for heating and cooling replacements. It's the installer's job to pull it, and the cost should be in your quote.
Our Commerce City ranch is from the 1970s — what usually comes up?
Electrical panels, ductwork condition, and venting are the big three in the 1960s–80s housing stock. None are deal-breakers, but they're why an in-home estimate beats a phone quote every time.
Get a straight answer on your furnace
Talk to a licensed local installer in Commerce City. Free second opinions on replacement quotes — no pressure, no obligation.
Typical response time: under 15 minutes, 7am–7pm daily.