How much does it cost to replace an AC unit in St. George?

A standard-efficiency central AC replacement runs $5,000–$8,300 installed. Across all efficiency tiers, central AC spans $5,300–$10,500, and high-efficiency systems reach $12,500–$14,000+. Replacing the furnace and AC together runs $10,500–$18,500. Size matters too: the common 3-ton system runs $5,800–$7,800.

How long do AC units last in southern Utah?

AC units in St. George and southern Utah typically last 10–15 years, versus the 15–20 year national rule of thumb. Systems here run near-continuously through triple-digit summers, and heat, runtime, dust, and UV all take years off compressors and fan motors. A well-maintained, correctly sized unit reaches the top of that range; an oversized or neglected one won’t.

Is a heat pump worth it in St. George?

A heat pump is a genuinely strong option in St. George: it’s an AC that also runs in reverse for heating, installed for $8,000–$15,000. St. George’s mild winters sit inside the range where modern heat pumps heat efficiently without backup, so one system can replace both your AC and furnace — worth pricing against a furnace-plus-AC combination when you’re quoted.

Why did I get a replacement quote under $4,000?

One published local estimate prices a basic like-for-like condenser swap at $2,576–$3,406 — real, but it typically excludes the matched indoor coil, line-set work, city permit, and disposal that a complete job includes. A too-cheap quote usually means mismatched components (which can void the equipment warranty) or a skipped permit. Make every quote itemize the same scope before comparing.

When should I replace instead of repair?

Multiply the unit’s age by the repair quote — over $5,000, lean replacement. Also lean replacement when a 10+ year-old unit needs compressor ($600–$2,500) or evaporator coil ($1,000–$4,500) work, or when it needs a recharge every summer — that’s a leak, and that money is better going toward a new system than into refrigerant that escapes by August.

How much does it cost to replace an AC unit in St. George?

A standard-efficiency central AC replacement runs $5,000–$8,300 installed. Across all efficiency tiers, central AC spans $5,300–$10,500, and high-efficiency systems reach $12,500–$14,000+. Replacing the furnace and AC together runs $10,500–$18,500. Size matters too: the common 3-ton system runs $5,800–$7,800.

How long do AC units last in southern Utah?

AC units in St. George and southern Utah typically last 10–15 years, versus the 15–20 year national rule of thumb. Systems here run near-continuously through triple-digit summers, and heat, runtime, dust, and UV all take years off compressors and fan motors. A well-maintained, correctly sized unit reaches the top of that range; an oversized or neglected one won’t.

Is a heat pump worth it in St. George?

A heat pump is a genuinely strong option in St. George: it’s an AC that also runs in reverse for heating, installed for $8,000–$15,000. St. George’s mild winters sit inside the range where modern heat pumps heat efficiently without backup, so one system can replace both your AC and furnace — worth pricing against a furnace-plus-AC combination when you’re quoted.

Why did I get a replacement quote under $4,000?

One published local estimate prices a basic like-for-like condenser swap at $2,576–$3,406 — real, but it typically excludes the matched indoor coil, line-set work, city permit, and disposal that a complete job includes. A too-cheap quote usually means mismatched components (which can void the equipment warranty) or a skipped permit. Make every quote itemize the same scope before comparing.

When should I replace instead of repair?

Multiply the unit’s age by the repair quote — over $5,000, lean replacement. Also lean replacement when a 10+ year-old unit needs compressor ($600–$2,500) or evaporator coil ($1,000–$4,500) work, or when it needs a recharge every summer — that’s a leak, and that money is better going toward a new system than into refrigerant that escapes by August.

Cost Guide · St. George, UT

AC & HVAC replacement cost in St. George, straight up

Researched from local + national pricing data · Last verified July 2026

Replacing an air conditioner is a five-figure decision at the high end and a four-figure one done right at the low end. Here’s what systems actually cost installed, why quotes for the same house spread by thousands, and how to know when it’s really time.

Quick answer

As of July 2026, replacing a central air conditioner in St. George, Utah costs $5,000–$8,300 installed at standard efficiency. The full central-AC span across efficiency tiers is $5,300–$10,500, high-efficiency systems run $12,500–$14,000+, a heat pump runs $8,000–$15,000, and replacing furnace + AC together runs $10,500–$18,500.

St. George Air Repair · independent local guide

Cost by system size

Size is measured in tons of cooling capacity, and in our heat, sizing is not a guess — a proper quote starts with a load calculation (ask for “Manual J”), not square footage alone. Typical installed ranges:

System size	Typically fits	Installed cost
2 tons	Smaller homes, casitas (~1,000–1,300 sq ft)	$5,000–$6,800
3 tons	The common St. George single-story (~1,500–1,800 sq ft)	$5,800–$7,800
4 tons	Larger single-story / modest two-story (~2,000–2,400 sq ft)	$6,500–$8,800
5 tons	Large homes (~2,500+ sq ft), or split across two units	$7,000–$9,500+

One St. George-specific note: our cooling loads run high for the square footage because of sustained 100°+ heat and sun exposure, so don’t be surprised if the correct size here is a half-ton above what a national calculator suggests. But bigger is not better — an oversized unit short-cycles, dehumidifies poorly, and wears itself out early.

Cost by efficiency (SEER2)

SEER2 is the current efficiency standard — higher means less electricity per hour of cooling. Efficiency pays back faster in St. George than almost anywhere: a system that runs near-nonstop from June through September multiplies every efficiency point.

Efficiency tier	Installed cost
Up to 13.4 SEER2 (minimum allowed)	$5,300–$7,900
14.0–14.7 SEER2	$6,700–$9,300
15.0–17.2 SEER2	$7,500–$10,600
16.5–18.5 SEER2	$9,100–$12,200
Top-tier variable-speed (to 25.8 SEER2)	$11,400–$17,300+

The sweet spot for most homes here is the mid tiers — meaningful summer savings without the premium of top-tier variable-speed equipment. If you’re quoted a high tier, ask the contractor to show the payback math against your actual summer utility bills.

The heat pump question

A heat pump is a central AC that also runs in reverse to heat your home, installed for $8,000–$15,000. St. George is close to ideal heat-pump territory: winters are mild enough that modern units heat efficiently without electric-resistance backup, and you replace two systems (AC + furnace) with one. If your furnace is also near end-of-life, price a heat pump against the $10,500–$18,500 furnace-plus-AC combination before deciding — and ask about current federal or utility incentives, which shift year to year.

Ductwork: the quote-day surprise

If your ducts leak, are undersized, or ran decades in an attic that hits 140°F, the best new system can’t fix that. Minor duct repair and sealing runs $300–$1,500; full replacement runs $1,400–$5,600+. A contractor who inspects your ducts before quoting is doing it right — in newer-construction areas like Washington City and Little Valley ducts are usually fine, while older central St. George homes are where duct surprises live.

How long systems really last here

The national rule of thumb says 15–20 years. In St. George, plan on 10–15. The reasons are the same ones that make summer bills high: near-continuous runtime through triple-digit months, compressor stress on 110° afternoons when the system works against a 35-degree temperature gap, desert dust loading filters and coils, and UV baking rooftop and south-facing units. Two practical takeaways: budget for replacement at year 10 rather than being ambushed at year 12 — and maintain the cheap stuff (filters, coil cleaning, $100–$350 capacitors) so heat is the only thing aging your system.

Repair or replace: the framework

Age × repair quote > $5,000 → replace. A 12-year-old unit with a $600 quote is at the line; in our climate, lean replace.
Compressor or evaporator coil on a 10+ year unit → replace. Those repairs run $600–$2,500 and $1,000–$4,500 — too much to sink into a system near end-of-life.
Needs a recharge every summer → replace. That’s a leak. Recharges at $150–$600 a season are a subscription to a dying system.
Under 8 years old with a specific failed part → repair. Most repairs land at $283–$408; see the repair cost guide.
Limping in late season → schedule, don’t panic. If it can cool through September, an October replacement beats a July emergency install on both price and scheduling — and if it dies mid-heat-wave first, our emergency guide covers bridging the gap.

What a legitimate replacement quote itemizes

A load calculation — the contractor measured, asked about insulation and windows, and can show the sizing math.
Equipment brand, model numbers, tonnage, and SEER2 — for both outdoor and indoor (coil) components, matched.
The city permit — replacements in St. George are permitted work; “no permit needed” is a red flag.
Line set and coil scope — reused or replaced, stated. This is where too-cheap quotes hide (one published local basic-swap figure of $2,576–$3,406 covers little beyond the box itself).
Labor warranty, in writing — separate from the manufacturer’s equipment warranty, and only valid if the installer is around to honor it — vet the company as carefully as the equipment.

How we researched these numbers

Installed-cost ranges come from current national cost databases (HomeGuide, 2026) cross-checked against published St. George installation estimates; the basic-swap caveat figure is a published local estimate shown with its limits stated. Climate and lifespan statements reflect St. George’s ~102°F July average highs. Where sources disagreed we show the wider range. Last verified July 2026; we re-check each season.