Full HVAC System Replacement Cost in the Denver South Metro (Furnace + AC Combo Pricing, 2026)

Why Replacing Both Systems Together Usually Wins

If your furnace and AC are both past 12–15 years old, replacing them together is almost always cheaper than doing them one at a time. You pay for one labor mobilization instead of two, the indoor coil and blower get matched to the new condenser (which protects efficiency and warranty coverage), and you pull one permit instead of two. Here's the complete 2026 combo pricing picture for Littleton, Highlands Ranch, Centennial, Lone Tree, and south Denver.

The Anatomy of a Full System Quote

Every honest full-replacement quote contains the same ingredients:

Furnace equipment:

• 80% basic single-stage: $800 – $1,200
• Mid-tier two-stage: $1,400 – $2,500
• High-end modulating 96%+: $3,000 – $6,000

AC condenser equipment (14–18 SEER2):

• 2 ton: $1,200 – $2,800
• 3 ton: $1,500 – $3,900
• 4 ton: $1,800 – $4,500
• 5 ton: $2,200 – $5,500

Labor:

• Standard install (accessible mechanical room, healthy ducts): $3,000 – $6,000
• Complex install (tight attic/crawl, major ductwork): $6,000 – $12,000

The line items that separate honest quotes from lowball bait:

• Permits & inspections: $150 – $500
• Line set replacement: $300 – $800
• Electrical upgrade/disconnect: $200 – $600
• Code upgrades: $300 – $2,000
• Smart thermostat: $150 – $450
• Extended warranty options: $150 – $1,000

If a quote is dramatically cheaper than the others, check whether permits, line set, and code items are missing. They'll reappear later as change orders.

Three Real Budget Tiers (3-Ton Home, Standard Labor)

Tier 1 — Reliable & Budget-Smart: roughly $7,500 – $11,000

80% single-stage furnace + 14.3 SEER2 single-stage AC (Goodman/Rheem class), permits, basic thermostat. Solid, warrantied heating and cooling with zero frills. The right call for rentals, pre-sale replacements, and tight budgets.

Tier 2 — The Comfort Sweet Spot: roughly $10,500 – $15,500

Two-stage mid-tier furnace + 16 SEER2 two-stage AC (Carrier/Trane class), smart thermostat, line set replacement, permits. Noticeably quieter and steadier than Tier 1, meaningful efficiency gains, strong resale story. This is what most of our South Metro customers choose.

Tier 3 — Premium Performance: roughly $15,000 – $24,000+

96%+ modulating furnace + 17–18 SEER2 variable-speed condenser (or cold-climate heat pump in a dual-fuel configuration), communicating smart thermostat, all venting and code work. Whisper-quiet, temperatures locked within a degree, maximum rebate eligibility. Worth it in larger homes (3,000+ sq ft) and forever homes.

Complex installations add $2,000 – $5,000 to any tier. Larger homes needing 4–5 ton equipment add roughly $500 – $2,000 in equipment cost.

Don't Leave Rebate Money on the Table

High-efficiency choices unlock money that budget equipment doesn't: federal 25C tax credits (up to $600 for qualifying furnaces, up to $2,000 for heat pumps), Xcel Energy equipment rebates, and Colorado's state heat pump credit if you go the dual-fuel route. On a Tier 3 system these commonly stack to $2,000 – $4,000+, narrowing the gap to Tier 2 substantially. We calculate applicable rebates into every estimate.

Timing Your Replacement Saves Real Money

The worst time to buy an HVAC system is the day yours dies in a July heat wave or a January cold snap — you'll pay peak-season pricing and take whatever equipment is in stock. If your system is 15+ years old and limping, replacing proactively in spring or fall typically saves 10–15% and gives you time to compare options properly.

What a Fairpoint Estimate Looks Like

We provide free in-home estimates with a proper load calculation (not a guess based on your old unit's sticker), multiple tiers priced side by side, every line item spelled out, and current rebate math included. No pressure, no games — just real numbers you can compare confidently.

Ready for real pricing on your home? Call Fairpoint Heating & Air at 303-929-9361 or request an estimate online. Serving Littleton, Highlands Ranch, Centennial, Lone Tree, and the Denver South Metro.