St. Louis Metro · Missouri & Illinois
Radon Mitigation Companies in St. Louis, MO: How to Choose One
Radon mitigation companies in St. Louis range from owner-operated specialists to national franchises and home inspectors who add mitigation as a sideline, and the difference shows up in the post-mitigation number, not the sales pitch.
This page lists what to verify before you hire any radon mitigation contractor in the St. Louis metro, and states plainly how Air Sense Environmental answers each question so you can hold us to it.
Air Sense Environmental is an owner-operated radon mitigation company headquartered in Edwardsville, Illinois, serving St. Louis City and County, St. Charles, Jefferson, Franklin, Madison and St. Clair counties.
What a Good Company Delivers
Every system is verified with a post-mitigation test against the EPA action level of 4.0 pCi/L.
Verified, not assumedLicensing
What licenses and certifications should a St. Louis radon mitigation company have?
A radon mitigation company working in the St. Louis metro should hold an Illinois IEMA mitigation license and a national certification such as NRPP or NRSB, because the metro straddles two states with different rules.
- Illinois: IEMA licensing is mandatory for anyone installing a radon mitigation system. You can look the license number up on the IEMA public registry.
- Missouri: no state license exists, so certification is the only credential you can check. Ask for the NRPP or NRSB certificate number.
- Insurance: ask for a certificate of liability insurance before anyone cores a hole in your slab.
Air Sense Environmental holds IEMA license #RNM20232346, is NRPP-certified, and is fully insured. The same crew and the same standard cover both sides of the river.
Design
How does the company decide where the system goes?
The best radon mitigation companies measure the sub-slab before they design, using a pressure field extension test to confirm how far one suction point can reach under your specific floor. Companies that skip that step guess, and a guessed system is the one that comes back at 4.5 pCi/L.
Ask three questions: Will you test the pressure field before quoting? How many suction points does my foundation need? What happens if the first test after installation is still above 4.0 pCi/L?
Air Sense Environmental runs diagnostic testing on every install, prices additional suction points only when the diagnostics call for them, and credits any budgeted point that turns out to be unnecessary. Our sub-slab depressurization page explains the method.
Compare
Radon mitigation companies compared: the questions that separate them
Use this table on any quote. The right column states what Air Sense Environmental commits to on every job, so you can compare it line by line with any other radon mitigation contractor in St. Louis.
| What to ask | Why it matters | Air Sense Environmental |
|---|---|---|
| Illinois IEMA license | Required by law in Illinois | #RNM20232346 |
| National certification | Only credential checkable in Missouri | NRPP-certified |
| Who does the work | Subcontracted crews vary job to job | Owner-led, Jake Lusby on site |
| Design method | Guessing suction points causes failed systems | Pressure field diagnostics on every install |
| Post-mitigation test | The only proof the system works | Included, target below 2.0 pCi/L |
| Written guarantee | Covers the follow-up reading | Yes, in writing |
| Estimate | Phone quotes miss foundation details | Free, written, in-home |
| Reviews | Volume and recency, not just the star count | 150+ five-star Google reviews |
Warning Signs
Red flags when hiring a radon mitigation contractor
Walk away from any radon mitigation company that quotes a fixed price over the phone without asking about your foundation, cannot name the certification it holds, or treats the post-mitigation test as an optional extra.
- No follow-up test. A system that is never tested is a system nobody has proven.
- Fan sized by habit. Oversized fans waste power and pull conditioned air; undersized fans fail in tight clay soils common across St. Louis County.
- Exhaust below the roofline or next to a window, which violates the ANSI/AARST mitigation standard.
- No manometer installed on the pipe, leaving you no way to see whether the fan is still pulling next year.
Our radon mitigation system installation page shows what a compliant install looks like, photo by photo.
Coverage
Radon mitigation companies serving both sides of the St. Louis metro
Air Sense Environmental installs and verifies radon mitigation systems throughout the St. Louis metro on both sides of the river: St. Louis City and County, St. Charles County, Jefferson County and Franklin County in Missouri, and Madison and St. Clair counties in Illinois.
The headquarters at 5237 Old Alton Edwardsville Rd, Edwardsville, IL puts the crew within a short drive of Metro East communities and the Missouri suburbs alike. See the full service area or the main radon mitigation page for system types, project readings and pricing factors.
Common Questions
Frequently Asked Questions About Radon Mitigation Companies in St. Louis
Do radon mitigation companies in Missouri need a license?
Missouri does not license radon mitigation companies, so anyone can advertise the service on the Missouri side of the metro. Illinois does license them: every radon mitigation professional working in Illinois must hold an IEMA license. Air Sense Environmental holds IEMA license #RNM20232346 and NRPP certification, and applies the same standard on both sides of the river.
How much do radon mitigation companies charge in St. Louis?
Radon mitigation companies in St. Louis typically charge $1,100 to $3,200 for an active sub-slab depressurization system, which is the most common design for area homes. Foundation type, the number of suction points and the fan size move the number more than anything else. Air Sense Environmental quotes every system after a free in-home assessment.
Should I get more than one radon mitigation quote?
Yes, but compare the design, not just the price. Two quotes for the same house can differ because one contractor ran a pressure field extension test and the other guessed at suction points. Ask each company how they decided where the pipe goes, whether a post-mitigation test is included, and what the written guarantee covers.
Who actually installs the system when I hire Air Sense Environmental?
Owner Jake Lusby leads every Air Sense Environmental installation. The crew is owner-led rather than subcontracted, which is why the person who designed the system is the person who tests it afterward.
How do I know the radon mitigation company’s system worked?
A post-mitigation radon test is the only proof. The EPA recommends testing no sooner than 24 hours and within 30 days of installation. Air Sense Environmental includes the follow-up test and designs every system to a target below 2.0 pCi/L, half the EPA action level of 4.0 pCi/L.
Ready to Compare
Get a written radon mitigation estimate in St. Louis
Bring this checklist to the estimate. Air Sense Environmental answers every line of it in writing before any work starts.