Festus, MO · Jefferson County

Furnace Installation Done Right From the First Startup

Exactly what's wrong. Exactly what it costs. In writing.

A new furnace should be sized for the home, connected correctly, and tested before the installation is considered complete. ExactAir evaluates the home’s heating needs, existing equipment, ductwork, airflow, electrical requirements, and installation conditions before the new furnace goes in.

Veteran-Owned · Family-Owned · EPA Certified · Fully Insured · Est. 2025

Signs You May Need a New Furnace

How do you know it's time to consider furnace replacement?

A furnace does not have to stop working completely before replacement becomes worth considering. Age, repeated repairs, declining performance, and changing comfort can all be reasons to evaluate a new furnace.

Frequent repairs — Repeated service calls can become difficult to justify on an aging furnace.
Poor heating performance — The system runs but struggles to keep the home comfortable.
Declining efficiency — A noticeable drop in performance can mean the furnace is working harder than it should.
Uneven temperatures — Rooms staying colder than others may indicate heating or airflow problems.
Rising heating bills — Increasing operating costs can be a reason to evaluate an older furnace.
Longer heating cycles — Extended run times may point to performance or sizing concerns.
An aging furnace — Older equipment may be worth evaluating before an unexpected breakdown.
Major repair needed — A costly repair can be a good time to compare repair and replacement options.

What Happens During a Furnace Installation

The furnace is only one part of the installation

A properly installed furnace needs to work with the home, ductwork, electrical system, controls, and other connected components. ExactAir evaluates those conditions before installation and verifies the completed system afterward.

Exact Home & System Evaluation

We review the existing furnace, heating concerns, home conditions, ductwork, airflow, and installation space before planning the replacement.

Exact Furnace Sizing

The replacement furnace is selected based on the home's heating requirements rather than automatically matching the size of the equipment being removed.

Exact Installation Planning

We identify the connections, clearances, electrical requirements, airflow considerations, and other installation details needed for the new furnace.

Exact Furnace Installation

The existing equipment is removed and the new furnace is installed according to the equipment requirements and the conditions of the home.

Exact System Connection

The furnace is connected to the existing HVAC system and controls, with attention given to airflow and proper system operation.

Exact Startup & Verification

We start the furnace, check operation, verify performance, and make sure the system is functioning properly before the installation is considered complete.

Why Jefferson County Homeowners Choose ExactAir for Furnace Installation

The furnace is sized for the home

We do not assume that the old furnace's size is automatically the right size for the replacement.

Installation considers the whole system

Ductwork, airflow, electrical requirements, controls, and installation conditions can all affect how a new furnace performs.

Clear recommendations before installation

You get an explanation of the proposed system and installation scope before the work begins.

Proper startup matters

A furnace installation is not finished when the equipment is physically in place. The system is started and checked to verify operation.

Owner-level accountability

ExactAir is veteran-owned and family-owned, with a focus on straightforward communication and properly completed HVAC work.

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

Furnace Installation in Festus & Jefferson County, MO

ExactAir is based in Festus and provides furnace installation throughout Jefferson County and the surrounding St. Louis Metro area, generally within about 45 minutes of Festus. If your existing furnace is aging, unreliable, or no longer keeping your home comfortable, we can evaluate the system and help determine the right replacement approach.

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 Heating Service

    
 
 
         
   KEITH CROWDEN 
 
 
 
 Trustindex verifies that the original source of the review is Google. Exactair did a great job installing my new Air Conditioner. Best price exceptional service I highly recommend Exact Air
  
 
        
   james blehm 
 
 
 
 Trustindex verifies that the original source of the review is Google. The technician  found what others couldn't.  He was timely and professional.  Pricing was easily affordable!  I will definitely be using them again for a new split system install. And would recommend to everyone!!
  
 
        
   Carole Kronmueller 
 
 
 
 Trustindex verifies that the original source of the review is Google. Exact AIR Is a wonderful HVAC business They are very efficient , reliable , affordable, and the best part is Brett Will give you personalized attention and make it a point if you have an emergency or not , to make it out and get you up and running. I highly recommend them, and I have shared their contact with several of my family members and friends that have asked. One other  note, it is a veteran owned company🇺🇸🇺🇸🇺🇸🇺🇸
  
 
        
   Guadalupe Rios 
 
 
 
 Trustindex verifies that the original source of the review is Google. I had a great experience with ExactAir Heating and Cooling from start to finish. Mr. Lahue  was  very knowledgeable, efficient, and made sure everything was working properly before leaving. The pricing was fair, and I appreciated the honest recommendations without any pressure to purchase unnecessary services. It's refreshing to work with a company that values quality and customer service. I would definitely recommend them to anyone looking for reliable AC repair or maintenance.  Promote Ahead of Peers.

Frequently Asked Questions

Furnace Installation FAQs

How much does furnace installation cost in Festus, MO?

Furnace installation costs depend on the equipment, home requirements, installation conditions, and any additional work needed to complete the system correctly. ExactAir provides pricing before installation begins.

How do you determine what size furnace my home needs?

Furnace sizing should be based on the home’s heating requirements rather than simply matching the existing furnace. ExactAir evaluates the home and system conditions before recommending equipment.

Can you install a furnace where a different heating system was used?

It depends on the existing system, available connections, ductwork, electrical requirements, and installation conditions. ExactAir evaluates the property before determining what installation approach is appropriate.

Do you inspect the existing ductwork during furnace installation?

Yes. Existing ductwork and airflow are relevant to how a new furnace performs, so they are considered as part of the installation evaluation.

How long does furnace installation take?

Installation time varies depending on the equipment and site conditions. ExactAir can explain the expected scope and timing before the work begins.

Do you test the furnace after installation?

Yes. The furnace is started and checked after installation to verify proper operation and system performance before the job is complete.

Install your new furnace with the sizing, setup, and testing your home deserves

Monday–Friday, 7am–7pm · 24/7 emergency service available