Festus, MO · Jefferson County

Furnace Replacement Built Around Your Home, Not Just Your Old Furnace

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

Replacing an aging furnace is an opportunity to correct problems that may have developed over years of operation. ExactAir evaluates your existing furnace, heating needs, airflow, ductwork, installation conditions, and replacement options before recommending the new system.

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

Signs You May Need Furnace Replacement

How do you know when it's time to replace your furnace?

A furnace does not have to completely fail before replacement becomes worth considering. Age, repeated repairs, poor performance, and increasing operating costs can all be reasons to evaluate a replacement.

Frequent repairs — Repeated breakdowns can make an aging furnace harder to justify.
Poor heating performance — The furnace runs but struggles to keep the home comfortable.
Rising heating costs — Increasing operating costs can signal declining system performance.
Uneven temperatures — Persistent cold rooms may indicate the existing system is no longer meeting the home’s needs.
Long heating cycles — Extended run times can point to performance or sizing concerns.
Major repair needed — A costly repair can be a good time to compare replacement options.
An aging furnace — Older equipment may be worth replacing before an unexpected failure.
Parts or service concerns — Difficulty supporting older equipment can make replacement worth evaluating.

What Happens During a Furnace Replacement

We evaluate the existing system before choosing what replaces it

A furnace replacement should not simply duplicate whatever equipment was installed before. ExactAir evaluates the home and existing HVAC system so the replacement is properly matched to the conditions it will operate in.

Exact Existing-System Evaluation

We review the current furnace, heating performance, comfort concerns, ductwork, airflow, and installation conditions.

Exact Heating Requirement Review

We evaluate the home's heating needs so the replacement furnace is not selected simply by matching the old unit's size.

Exact Replacement Planning

The installation space, connections, electrical requirements, airflow, controls, and other system considerations are reviewed before equipment is ordered.

Exact Furnace Selection

We explain the replacement options that fit the home and the differences that matter for your installation.

Exact Furnace Replacement

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

Exact Startup & Verification

The new furnace is started, tested, and checked for proper operation before the replacement is considered complete.

Why Jefferson County Homeowners Choose ExactAir for Furnace Replacement

The new furnace is sized for the home

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

Existing system conditions are considered

Ductwork, airflow, electrical requirements, controls, and installation space can all affect furnace performance.

Clear options before the project

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

The completed system gets tested

The furnace is started and checked after installation to verify proper operation.

Owner-level accountability

ExactAir is veteran-owned and family-owned, with a focus on straightforward communication from evaluation through final startup.

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 Replacement in Festus & Jefferson County, MO

ExactAir is based in Festus and provides furnace replacement throughout Jefferson County and the surrounding St. Louis Metro area, generally within about 45 minutes of Festus. If your furnace is aging, unreliable, expensive to repair, or no longer heating the home properly, we can evaluate the existing system and help you understand your replacement options.

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 Furnace 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 Replacement FAQs

How much does furnace replacement cost in Festus, MO?

The total cost depends on the furnace, home requirements, installation conditions, and any additional work needed. ExactAir provides pricing before the replacement begins.

Should I repair my furnace or replace it?

The decision depends on the furnace’s condition, repair needs, age, performance, and cost of continued repairs. ExactAir can evaluate the existing system and explain the available options.

How do you determine what size replacement furnace I need?

The replacement should be matched to the home’s heating requirements rather than automatically matching the old furnace. ExactAir evaluates the home before recommending equipment.

Can you replace my furnace with a different size?

A different furnace size may be appropriate depending on the home’s heating requirements and system conditions. ExactAir evaluates those factors before selecting the replacement.

Will you check my ductwork during furnace replacement?

Yes. Ductwork and airflow are important to how a replacement furnace performs, so they are considered during the replacement evaluation.

Do you test the furnace after replacement?

Yes. The new furnace is started and checked after installation to verify proper operation before the project is complete.

When your old furnace is ready to go, replace it with a system that actually fits your home

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