Festus, MO · Jefferson County
Dual Fuel Systems That Balance Heat Pump Efficiency With Reliable Backup Heat
Exactly what's wrong. Exactly what it costs. In writing.
ExactAir evaluates your home, existing equipment, airflow, controls, and system setup before recommending how the two systems should work together.
Veteran-Owned · Family-Owned · EPA Certified · Fully Insured · Est. 2025
When a Dual Fuel System May Make Sense
Do You Need Both a Heat Pump and a Furnace?
Dual fuel can be a practical option for homeowners who want heat pump operation during milder weather while keeping a furnace available when additional heating capacity is needed.
- Want heat pump efficiency — Use the heat pump when conditions are favorable for efficient operation.
- Need stronger backup heat — A furnace can provide additional heating when outdoor temperatures drop.
- Replacing aging equipment — Older heating equipment may be a good reason to evaluate a combined system.
- Uneven winter comfort — Existing heating limitations can signal the need for a different system approach.
- High heating demand — Larger or harder-to-heat homes may benefit from having two heating sources.
- Considering a heat pump — Dual fuel provides an alternative to relying on a heat pump alone.
- Existing furnace still has value — A serviceable furnace may potentially become part of a new system configuration.
- Want heating flexibility — Two heat sources give the system more than one way to meet heating demand.
What Actually Happens During a Dual Fuel System Visit
Before recommending equipment, ExactAir looks at how the complete heating system will operate together.
Evaluate the Home
We review the home's heating requirements, comfort concerns, existing HVAC equipment, and installation conditions.
Inspect the Existing System
The furnace, heat pump, ductwork, electrical connections, controls, and other relevant components are checked for compatibility and condition.
Review Heating Requirements
We determine what the system needs to accomplish rather than automatically matching the size of the equipment being replaced.
Plan the System Configuration
The heat pump, furnace, controls, airflow, and changeover strategy are considered as one connected heating system.
Complete the Service
Equipment and system components are installed, adjusted, repaired, or configured according to the planned setup.
Test Both Heating Sources
The system is operated through its available heating modes to confirm that the equipment, controls, airflow, and changeover operation are working correctly.
Why Jefferson County Homeowners Choose ExactAir for Dual Fuel Systems
The Complete System Gets Considered
A dual fuel setup only works well when its components operate together properly.
Heating Conditions Matter
Recommendations are based on the home's requirements and system configuration.
Existing Equipment Isn't Discarded
We evaluate whether usable equipment can remain part of the solution.
Controls Matter as Much as Equipment
Proper operation depends on how the heat pump and furnace communicate and switch between heating modes.
The ExactAir Method Guides the Work
We diagnose, document, explain, complete the work, and verify the result.
Where "Exact" comes from
ExactAir Heating and Cooling was founded in 2025 by Brett Lahue — an Army veteran who learned the trade the old way, checked off job by job under his father, a by-the-book technician himself.
When a job was done right, the answer was always the same word: “Exactly.” The name, and the standard behind it, stuck.
Today ExactAir is a small, owner-operated company serving Festus and Jefferson County — background-checked, EPA certified for both Universal and A2L refrigerants, and insured through Federated Insurance.
— Brett Lahue, Owner & Lead Technician
Dual Fuel System Service in Festus & Jefferson County, MO
ExactAir provides dual fuel system installation, service, and support in Festus and surrounding Jefferson County communities, generally within about 45 minutes of Festus.
Note: A trip fee applies past the standard service radius. Service inside St. Louis city and St. Louis County is currently limited, pending additional licensing there.
What Customers Say About ExactAir's HVAC Service
Frequently Asked Questions
Dual Fuel Systems FAQs
What is a dual fuel HVAC system?
A dual fuel system uses a heat pump as one heating source and a furnace as another. The system is configured to use the appropriate source based on operating conditions and system setup.
Is a dual fuel system the same as a heat pump?
No. A heat pump can provide heating and cooling by itself, while a dual fuel system combines a heat pump with a separate furnace for backup or supplemental heating.
Can my existing furnace work with a new heat pump?
Possibly. Compatibility depends on the furnace, heat pump, controls, ductwork, electrical requirements, and overall condition of the existing system. ExactAir can evaluate the setup before recommending a configuration.
Does a dual fuel system also provide air conditioning?
Yes. A heat pump provides cooling as part of its normal operation, so a dual fuel configuration can provide both heating and cooling.
Is dual fuel a good option for every home?
Not necessarily. The home’s heating requirements, existing equipment, ductwork, electrical setup, installation conditions, and homeowner goals all matter when determining whether a dual fuel configuration makes sense.
Can ExactAir replace my old furnace and add a heat pump?
ExactAir can evaluate the existing heating and cooling system and determine what equipment and configuration may be appropriate for the home.
Get a Dual Fuel System Designed to Work as One Complete Heating Solution
Whether you’re upgrading an aging system or considering a heat pump with furnace backup, ExactAir will look at the whole setup before recommending what comes next.
