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How much does an AC replacement cost in Longmont, CO?

US national rangeUpdated Prices checked October 20262 sources

An AC replacement costs $3,887 to $8,073 nationally, typical $5,978. We have no documented price index for Longmont for this job, so this is the US national range from HomeAdvisor, checked October 2026.

US national range, not adjusted for this city

Low
$3,887
Typical
$5,978
High
$8,073

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AC replacement cost in Longmont, CO

We have no documented price index for Longmont for this job, so the table shows the US national range.

AC replacement cost in Longmont, CO
EstimateLowTypicalHighBasisChecked
US national range$3,887$5,978$8,073Per system, installed (unit plus labor); typical range of customer-reported jobs (HomeAdvisor)October 2026

AC replacement cost by type or size

US national figures in USD, as published by each source.

AC replacement cost by type or size
Type or sizePrice (USD)Source
3-ton central AC replacement, existing ducts$5,500 to $10,000Fixr
3-ton central AC replacement with new ducts$7,500 to $16,000Fixr

What drives the cost of an AC replacement

  1. System size

    Capacity in tons depends on home size, climate, sun exposure and insulation.

  2. Efficiency (SEER2)

    Higher-efficiency units cost more up front and less to run.

  3. Ductwork

    New ductwork is the largest add-on, at $1,000 to $5,000.

  4. System type

    Split, packaged, heat pump and ductless systems are priced differently.

  5. Electrical and drain work

    A panel upgrade or new condensate line adds cost.

  6. Labor

    Installation typically takes four to eight hours, about $300 to $1,600 in labor.

Permits and what's included in Longmont

Permit note

A mechanical or electrical permit and an inspection are usually required. Ask whether the quote includes them.

Rules are set locally; confirm with Longmont’s building department.

What’s usually included

  • The new outdoor and indoor equipment
  • Refrigerant lines, electrical connection and startup
  • Removal of the old unit (confirm on the quote)

Scopes vary. Get the scope in writing on every quote.

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Top-ranked HVAC contractors in Longmont

The top 3 of 480 HVAC contractors we rank for Longmont, CO, by CR Score. Paid placement never changes rank.

  1. #1
    M and M Heating, Cooling, Plumbing and Electrical
    CR Score 674.9from 3,075 Google reviews
  2. #2
    Welzig Heating, Air, Plumbing & Electric
    CR Score 664.9from 1,269 Google reviews
  3. #3
    Blue Valley Heating & Cooling
    CR Score 654.8from 1,093 Google reviews

See all ranked HVAC contractors in Longmont

AC replacement cost in Longmont: questions

How much does an AC replacement cost in Longmont, CO?

An AC replacement costs $3,887 to $8,073 nationally, typical $5,978. We have no documented price index for Longmont for this job, so this is the US national range from HomeAdvisor, checked October 2026.

Do I need a permit for an AC replacement in Longmont?

A mechanical or electrical permit and an inspection are usually required. Ask whether the quote includes them. Rules are set locally, so confirm with Longmont’s building department.

What affects the cost of an AC replacement?

System size: capacity in tons depends on home size, climate, sun exposure and insulation. Efficiency (SEER2): higher-efficiency units cost more up front and less to run. Ductwork: new ductwork is the largest add-on, at $1,000 to $5,000. System type: split, packaged, heat pump and ductless systems are priced differently.

How many HVAC contractors serve Longmont?

We rank 480 HVAC contractors for Longmont, CO by CR Score. Get at least three written quotes for the same scope.

What is usually included in the price?

The new outdoor and indoor equipment; Refrigerant lines, electrical connection and startup; Removal of the old unit (confirm on the quote). Always get the scope in writing on the quote.

Sources

Checked October 2026. Figures are estimates, not quotes.

  1. HomeAdvisor: AC unit installation cost · page updated June 17, 2026 · checked October 2026Primary source. Used for: Low, typical and high; ductwork, labor and efficiency drivers.
  2. Fixr: Central air conditioner installation cost · page updated August 29, 2025 · checked October 2026Used for: 3-ton replacement ranges with and without new ducts; drivers; permit.
These are published estimates, checked October 2026. They are not quotes. Typical range shown: $3,887 to $8,073. Editorial policy

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