How Much Does a Furnace and AC Replacement Cost in St. Louis, MO? [2026 Data]

In St. Louis, MO, it costs an average of $7,133 to replace a furnace and AC, with most projects ranging from $4,755 to $11,888. Factors like your home’s size and the system type significantly affect how much you’ll pay. Let’s review the other factors that affect the cost of a furnace and AC replacement so you can create an informed budget for this St. Louis, MO, home update. 

Furnace and AC Replacement Cost Factors 

HVAC replacement costs in St. Louis, MO depend on the type and size of the system. Labor rates and the brand you choose can also affect your final price. 

Type of HVAC System

There are four types of HVAC systems, including split systems, duct-free systems, hybrid systems, and packaged heating and air systems. The typical cost ranges for each are:

• Split systems: $3,614–$7,133

• Duct-free systems: $1,902–$13,790

• Hybrid systems: $2,378–$9,510

• Packaged heating and air systems: $9,510–$13,314

Unit Size

The square footage of your house will determine what size furnace and air conditioner you need to heat or cool your space efficiently. A local HVAC company can help you determine what size you need exactly by doing a load calculation.

Unit Brand

An HVAC system costs about $4,750 on average, but the brand you buy can change this number. For example, brands like Amana or Coleman tend to come in the lower end of the spectrum at $3,000, while brands Trane and York are often $6,000 or more.

HVAC Pro Costs

Beyond the cost of the HVAC system, your total price when hiring a St. Louis HVAC pro will also include labor rates and permit fees. In St. Louis, MO labor costs can vary based on the age and layout of the home. Many properties in the area have basements and existing ductwork, which can simplify installations compared to homes that need full retrofits. However, older systems and tight mechanical spaces can still add time, complexity, and cost to the project. 

Permits

HVAC replacements in St. Louis generally require permits, especially for full system installs and changes involving gas lines, electrical components, or ductwork. Permits help ensure the work meets local safety and building codes. Contractors typically pull permits on your behalf, but the cost is passed along to you as part of the project.

Licensing and Insurance

Contractors in St. Louis need to be licensed and insured. General liability insurance and workers’ compensation are standard and protect both you and the crew in case unexpected problems occur during installation. The cost for pros to maintain these requirements contributes to their overall pricing, but it helps ensure the work is completed safely and professionally. 

Taxes

In St. Louis, sales tax on HVAC materials and equipment is typically around 9.7%, though rates can be higher in certain areas depending on local districts. Labor is generally not taxed when it’s part of an installation project. Check your estimate to make sure you’re only paying tax on materials and not on labor.

Does Replacing Your AC and Furnace Increase Home Value?

Yes, installing a new HVAC system can increase your St. Louis home’s value between 5% and 7%, with an overall return on investment (ROI) of about 30%. Replacing your AC and furnace can improve your home’s value, but the biggest benefit is increased buyer appeal rather than a full return on investment. In St. Louis, where many homes rely on older systems, a new setup can make your home more attractive to buyers and reduce concerns during inspections.

How Angi Gets Its Local Cost Data 

To help homeowners plan their next project, Angi provides readers with carefully researched cost data and upholds strict editorial standards. We start with national average project costs, which we collect by analyzing competitor information, retailer material costs, and input from professional contractors. We then apply local price index data to calculate location-specific estimates that reflect what homeowners typically pay in their local area. To do that, we use data from the U.S. Bureau of Economic Analysis (BEA), including its Regional Price Parities (RPPs), which measure price differences across cities. This helps us account for differences in labor, materials, and overall cost of living, so estimates in higher- or lower-cost areas better reflect real-world local pricing.

Every estimate undergoes a thorough editorial review to verify accuracy, consistency, and alignment with observed market conditions.

Want to help us improve our cost data? Send us a recent project quote to [email protected]. Quotes and personal information will not be shared publicly.