HVAC Company Serving O'Fallon & Dardenne Prairie, MO

St. Charles County's two fastest-growing cities have a lot in common when it comes to HVAC: newer construction, two-story open floor plans, and a large share of builder-installed systems approaching the 12 to 15 year mark. Martin-Jetco Heating and Air Conditioning, family-owned and operated since 1964, serves all of it, with licensed, NATE-certified technicians who size replacements correctly, give you clear repair-versus-replace guidance, and handle whatever comes next.

Here is what a call to Martin-Jetco Heating and Air Conditioning typically covers for O'Fallon and Dardenne Prairie homeowners:

• A same-day diagnosis when something is wrong
• Honest repair options with clear pricing before any work starts
• A properly sized replacement when repair no longer makes sense
• Financing, rebates, and tax credit guidance on every project
• Seasonal maintenance that keeps a new system running efficiently for years

If your system cannot keep up with Missouri heat, humidity, or winter cold, call (636) 205-1631 or message us online to get options that fit your home and budget.

Our Full HVAC Services

• AC Repair
• AC Installation
• AC Replacement
• Furnace Repair
• Furnace Installation
• Furnace Replacement
• Heat Pump Services
• Indoor Air Quality
• Ductless Mini-Splits
• HVAC Maintenance
• Emergency HVAC Service

Additional services include boilers, geothermal systems, air scrubbers, whole-home humidifiers and dehumidifiers, air balancing, thermostat installation and repair, and commercial heating and air conditioning. Financing is available for larger projects.

How Much Does HVAC Replacement Cost in O'Fallon & Dardenne Prairie?

When repair no longer makes sense, most replacements in this area fall into two ranges:

• Air Conditioner & Evaporator Coil Replacement: approximately $5,500 to $9,200
• Complete HVAC System Replacement: approximately $8,450 to $22,990+

Factors that affect HVAC replacement pricing:

• Home square footage
• System tonnage requirements
• SEER2 efficiency rating
• Single-stage vs variable-speed equipment
• Existing ductwork condition
• Zoning systems
• Electrical or code upgrades
• Indoor air quality add-ons
• Accessibility of installation area

The cost to replace an HVAC system in O'Fallon or Dardenne Prairie typically ranges from approximately $5,500 to $9,200 for an air conditioner and evaporator coil replacement, while a complete system replacement generally runs from approximately $8,450 to $22,990 or more. 

Newer construction in this area often features larger two-story floor plans and open layouts, which require accurate load calculations to size a replacement correctly. Homes with ductwork that was never fully balanced, or those adding zoning and higher-efficiency variable-speed equipment, tend to land toward the upper end of the range.

If you are weighing repair against replacement, here are some repair costs for reference:

• Capacitors: $150 to $450
• Thermostats: $100 to $600
• Ignitor replacement: $180 to $350
• Flame sensor: $180 to $340
• Furnace capacitor: $150 to $350
• Blower motor: $500 to $1,400+
• Evaporator coil: $600 to $2,000
• Control board: $700 to $1,650
• Heat exchanger: $2,000 to $4,000
• Compressor-related failures: well over $1,000

When a repair cost is approaching a third of a new system's price, replacement usually pays back within a few years through lower bills and fewer service calls. An in-home evaluation is the only way to price the exact work your home requires.

Weighing a repair quote against a new system? Request an estimate online or call (636) 205-1631.

Get Same-Day & Emergency HVAC Service

A broken furnace in January or a dead AC in July cannot wait. Martin-Jetco Heating and Air Conditioning offers emergency HVAC service including evenings, weekends, and holidays, with licensed, NATE-certified technicians dispatched as quickly as possible:

• Morning calls often mean same-day visits, sometimes with a technician at the door that afternoon or within the hour
• After-hours calls reach a real person, with service dispatched quickly
• A diagnosis and repair quote come on the same visit, so nothing stalls
• Most repairs resolved within 24 to 48 hours of the first call

When making a call in a pinch, it helps to know what other homeowners experienced first. Read our 1,000+ five-star Google reviews before you dial (636) 205-1631.

Making the Cost of Your HVAC Replacement or Repair Manageable

Several programs help reduce what you pay out of pocket on a new system:

• Financing that spreads the cost into predictable monthly payments
• Spire utility rebates, filed on your behalf at the time of installation
• Federal energy-efficiency tax credits on qualifying high-efficiency equipment
• Seasonal coupons that trim the total further

We walk through all of it during your visit so you can compare equipment cost, monthly payment, and available savings before committing. You can also call us directly at (636) 205-1631 to ask about payment options and available rebates!

HVAC Challenges Common in O'Fallon & Dardenne Prairie Homes

Much of the housing stock in O'Fallon and Dardenne Prairie went up quickly between the late 1990s and the 2010s, and that speed shows up in HVAC details that become problems over time:

• Builder-grade equipment. Systems installed during the building boom were sized and selected to meet code and close a sale, not to optimize comfort or longevity. Many are now approaching the end of a 12 to 15 year lifespan having run at or near capacity since day one.
• Unbalanced ductwork. Two-story and open-plan homes in subdivisions like WingHaven, BaratHaven, and the Streets of Caledonia often have ductwork that was never properly balanced, leaving the upper level consistently warmer than the main floor in summer.
• Undersized systems for actual square footage. A system sized to the minimum required by code may hold temperature on a mild day but fall behind when the heat and humidity peak in July or August.
• Open floor plans and high ceilings. These design features are common across newer O'Fallon and Dardenne Prairie construction and change how air moves through the home. Equipment that was adequate for the original layout may not keep up as rooms are finished, additions are added, or layouts are opened up.
• Humidity control. Missouri summer humidity follows a system that short-cycles or runs intermittently, leaving the house cool but clammy. A properly sized system runs longer cycles and pulls more moisture from the air.
• Smart thermostats and zoning. Many homeowners in this area have added smart thermostats as a first step toward better temperature control between floors and rooms, but a thermostat upgrade only helps if the underlying ductwork and equipment are up to the job.

One of these matching what you are dealing with at home? Schedule an assessment visit online or call (636) 205-1631.

Neighborhoods & Areas We Serve

Martin-Jetco Heating and Air Conditioning serves homeowners and businesses throughout O’Fallon and Dardenne Prairie, including the 63366 and 63368 zip codes, along with surrounding St. Charles County communities.

In O’Fallon, the team serves established and growing residential areas, including The Streets of Caledonia, the Villages at Hutchings Farm, Patriots Landing, Deer Creek, The Crossings, and homes near Fort Zumwalt Park, the Renaud Center, CarShield Field, and Alligator’s Creek Aquatic Center. Service is also available around Progress West Hospital, the SSM Health Outpatient Center on Caledonia Parkway, and commercial corridors along Bryan Road, Mexico Road, and Highway K.

In Dardenne Prairie, service is available in and around WingHaven, BaratHaven, the Courtyards at BaratHaven, Inverness, Dardenne Greenway, Bluebird Meadow Park, and Dardenne Town Square. The team also works near Highway N, Fort Zumwalt West High School, Ostmann Elementary, and St. Charles Community College’s Dardenne Creek Campus.

Six Decades of Work Behind Every Recommendation

Martin-Jetco Heating and Air Conditioning has served the St. Louis region since 1964 and remains family-owned and operated. Every technician on the job is licensed and NATE-certified, and the company installs York, Goodman, Daikin, Carrier, and Trane, so the system is matched to your home rather than to one product line. No high-pressure sales tactics come with any of it, and if a job needs a second look after installation, the team comes back and makes it right.

More than 1,000 five-star Google reviews, an A+ rating with the Better Business Bureau, six Angie's List Super Service Awards, and recognition as a York Dealer of the Year many years running. See for yourself what homeowners say.

Year-Round Coverage with the Home Comfort Agreement

The Martin-Jetco Heating and Air Conditioning Home Comfort Agreement keeps a new system running at its best with a spring tune-up before cooling season and a fall tune-up before heating season. Membership also includes:

• Priority scheduling when you need service
• A discounted diagnostic fee on office-hours service calls
• 20% off parts and labor on service repairs
• No overtime fees
• A full safety and performance check at every visit
• Documented HVAC maintenance that keeps your manufacturer warranty in good standing

A new system runs best when it's maintained. Learn about the Home Comfort Agreement or call (636) 205-1631 to add it when you schedule your replacement.

Frequently Asked Questions

What zip codes do you serve in O'Fallon and Dardenne Prairie?

Martin-Jetco Heating and Air Conditioning serves all of O'Fallon and Dardenne Prairie, including the 63366 and 63368 zip codes, along with the surrounding St. Charles County communities.

How much does HVAC replacement cost in O'Fallon and Dardenne Prairie?

An air conditioner and evaporator coil replacement typically runs approximately $5,500 to $9,200, while a complete system replacement runs approximately $8,450 to $22,990 or more. Home size, floor plan layout, ductwork condition, equipment type, and efficiency rating determine where the project lands.

How much does AC repair cost in O'Fallon or Dardenne Prairie, MO?

AC repair costs vary widely depending on the problem. Minor repairs like capacitors ($150 to $450) or thermostats ($100 to $600) fall on the lower end. More involved work, including evaporator coil problems ($600 to $2,000) or compressor-related failures, can run well over $1,000. Blower motor repairs typically run $500 to $1,400 or more. We can give you an exact estimate after an in-home evaluation, which you can schedule online or by calling (636) 205-1631.

How much does furnace repair cost in O'Fallon or Dardenne Prairie, MO?

Furnace repair costs depend on the part and the complexity of the repair. Ignitor replacement typically runs $180 to $350, a flame sensor $180 to $340, a furnace capacitor $150 to $350, and a blower motor $500 to $1,400 or more. More serious repairs like a control board ($700 to $1,650) or heat exchanger ($2,000 to $4,000) cost significantly more and may tip the decision toward replacement. Call (636) 205-1631 to request an estimate for your HVAC project.

My home is only 10 to 15 years old. Why would I need a new system already?

Builder-grade systems installed during O'Fallon and Dardenne Prairie's rapid growth years were often sized and installed to meet minimum code rather than maximize longevity. A system that has run at or near capacity since installation can reach the replacement window sooner than expected. An evaluation gives you a clear picture of where the system actually stands.

Why is my AC running but not cooling my home?

Several causes are possible: a dirty filter, low refrigerant, a frozen evaporator coil, a failing capacitor, a clogged outdoor condenser coil, ductwork problems, thermostat issues, or a system that simply can no longer keep up with Missouri humidity. In newer St. Charles County homes with open floor plans or two-story layouts, airflow and system sizing can also play a significant role. A technician should check refrigerant levels, measure airflow, inspect the coil and condenser, and determine whether the issue is a simple repair or a larger system problem.

Why is my furnace blowing cold air?

Cold air from a furnace usually points to a dirty filter, thermostat setting issue, ignition or pilot problem, flame sensor failure, gas supply interruption, tripped limit switch, or a control board that has stopped communicating with the burners. In some cases, the blower keeps running after the burners shut down, which is why the air feels cold. Because these issues involve gas and combustion components, the problem should not sit. Martin-Jetco Heating and Air Conditioning can inspect the system, identify the cause, and confirm it is safe before returning it to service.

Are heat pumps effective during Missouri winters?

Yes, modern peat pumps can handle Missouri's climate well, providing both heating and cooling in one system. Martin-Jetco Heating and Air Conditioning evaluates the home, comfort goals, insulation, ductwork, and energy usage before recommending either direction. Call (636) 205-1631 to ask about our heat pump services.

How long does a new HVAC system last?

With regular maintenance, a quality system typically lasts 12 to 15 years, and some run longer when properly sized, installed, and serviced. St. Charles County's humid summers and cold winters place steady demand on both air conditioners and furnaces. Spring tune-ups, fall heating inspections, clean coils, regular filter changes, and prompt attention to small issues all help extend equipment life and protect warranty coverage.

How long does installation take?

Most single-system replacements are completed in one day. Projects that include ductwork corrections, zoning, or electrical updates may take longer, and Martin-Jetco Heating and Air Conditioning gives you a clear timeline during the evaluation so there are no surprises.

Get Clear HVAC Answers for Your O'Fallon or Dardenne Prairie Home

Whether you are comparing repair versus replacement, pricing a new system, dealing with a breakdown, or planning ahead with maintenance, Martin-Jetco Heating and Air Conditioning can help. Call (636) 205-1631 or schedule your in-home evaluation online today.