Festus, MO · Jefferson County

New AC Installation, sized to your home — not to the truck.

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

ExactAir installs residential air conditioning systems across Jefferson County, from new construction to full system replacements. Every install starts with a real assessment of your home, not a one-size unit off the shelf.

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

IS IT TIME FOR A NEW SYSTEM?

Signs a new AC installation makes more sense than another repair

Not every AC problem calls for a new system — and we’ll tell you when a repair is still the right call. These are the general signs worth an honest look.

The system is around 12–15 years old or older
Repairs are becoming frequent or increasingly costly
Your energy bills keep climbing without a clear reason
The system still uses R-22 refrigerant, which is being phased out
Rooms cool unevenly no matter what you try

HOW AN EXACTAIR INSTALLATION WORKS

The same ExactAir Method™, applied to your installation.

An install is only as good as the assessment behind it. Here’s what happens before, during, and after your new system goes in.

Exact Assessment

We evaluate your home — square footage, insulation, ductwork, and existing equipment — instead of matching whatever's on the truck.

Exact Sizing

The new system is sized to your home's actual cooling load, not rounded up or down to the nearest unit in stock.

Exact Options

You see the equipment options that fit your home and budget, with the reasoning behind each one, before you decide.

Exact Pricing

You know the full installed cost before any work begins. No surprises after the job starts.

Exact Installation

Installed to manufacturer requirements — proper refrigerant charge, airflow, and electrical connections, done right the first time.

Exact Verification

We test the finished system and walk you through it before we call the job complete.

Five reasons homeowners trust us with a new install

An exact diagnosis in writing

You see what we checked, what we found, and what it will cost before making a decision.

Real measurements, not guesswork

Actual equipment readings and a thorough checklist to size your new system correctly.

No unnecessary replacement pressure

If a dependable repair makes sense, we'll show you — instead of automatically pushing a new system.

Work completed to the proper standard

Installations follow manufacturer requirements and are tested before we call the job finished.

Local, owner-level accountability

Clear communication, respect for your home, and work from someone personally responsible for 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

Adding a room without ductwork, or cooling a garage or addition?

Ductless mini-split installation is handled on its own page.

Based in Festus, ExactAir installs across Jefferson County

Covering Jefferson County and the edge of the St. Louis metro. Don’t see your town? Call us — a trip fee may apply outside our primary service area, and we’re glad to tell you upfront if you’re too far out.

What Jefferson County homeowners say about their new AC

    
 
 
         
   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.

Common questions

AC Installation Questions, answered plainly

How long does a new AC installation take?

A straightforward system replacement is typically completed in a day. Homes needing ductwork changes or new construction installs can take longer — we’ll walk you through the timeline during your estimate.

What size AC system does my home need?

The right size depends on your home’s square footage, insulation, windows, and layout — not a generic rule of thumb. That’s why sizing is part of the assessment, not something we guess at over the phone.

Do you install any brand of air conditioner?

The right equipment depends on your home and budget. Ask us during your estimate and we’ll walk you through the options that make sense for your situation.

Do you install ductless mini-split systems too?

Yes — mini-split installation is handled as its own service. See our ductless mini-split page for details.

What areas do you install in?

ExactAir is based in Festus, Missouri and installs across Jefferson County and the surrounding St. Louis metro, sending a truck up to about 45 minutes out. Priority communities include Festus, Herculaneum, Crystal City, Pevely, Imperial, Barnhart, Hematite, Hillsboro, Mapaville, Desoto, Bloomsdale, Cedar Hill, House Springs and Arnold.

Ready for an AC installation sized to your home?

Mon–Fri 7:00 AM–7:00 PM · Sat–Sun closed · 24/7 emergency service