The homeowner’s reference
Radon mitigation cost: what changes the quote
EPA's Consumer's Guide to Radon Reduction says most homes can be fixed for about the same cost as other common home repairs. Costs vary with the size and design of the home and which reduction methods are needed. The guide says to get an estimate from one or more qualified contractors. It does not give a dollar amount for installing a system.
Sources: EPA: Consumer's Guide to Radon Reduction (2025, PDF).
1. The foundation and the system
EPA groups homes by foundation design: basement, slab-on-grade, or crawlspace. Many homes combine more than one, such as a basement under part of the house and a slab or crawlspace under the rest. Ask the contractor to inspect that structure before pricing the work. If the inspection is not enough, diagnostic tests help choose the system, and a contractor may charge for those tests even when the estimate itself is free.
Soil suction is the approach EPA generally recommends. It draws soil gas from under the home and vents it above the roof. The version follows the foundation: subslab suction for a basement or slab, drain-tile or sump suction where those features exist, block-wall suction for hollow block walls, and a membrane over a dirt crawlspace. Sealing cracks is a basic part of most approaches because it makes the other work more effective. EPA does not recommend sealing alone. By itself, sealing has not been shown to lower radon levels significantly or consistently.
The same guide says it is almost always less expensive to build radon-resistant features into a new home than to reduce radon in an existing one. It gives no dollar difference. A new home with those features should still be tested after people move in.
Sources: EPA: Consumer's Guide to Radon Reduction (2025, PDF).
2. The fan, the power, and the permits
An active system uses a fan, and the fan has to run continuously or the system does not work. EPA says fan systems reduce radon more effectively and will slightly increase the electric bill. Any change in heating or cooling cost depends on the climate, the system, and how the home is built. The guide does not say by how many dollars those bills will change.
The exhaust fan must not sit in or below a living area. EPA's example is unconditioned space. A fan mounted outside has to meet the local code for exterior use, and the electrical connections have to follow the local electrical code. Fans may last five years or more, and manufacturer warranties tend not to exceed five years. Replacing one is priced from labor and materials. Ask for estimates before that later work begins. The guide publishes no replacement price.
Before you sign, the contract should state the total cost of the job, including taxes and permit fees, any deposit, and when the balance is due. It should say the contractor will obtain the required permits and follow the building code. Those lines are what make two proposals comparable.
Sources: EPA: Consumer's Guide to Radon Reduction (2025, PDF).
3. The test after the system is running
EPA says to test within 30 days of installation, and no sooner than 24 hours after the system is running with the fan on, if it has a fan. A two- to seven-day measurement is the check the guide recommends. Keep windows and outside doors closed for 12 hours before the test and during it, except for ordinary entry and exit.
The contractor may test to check the installation. EPA also recommends an independent measurement, by another tester or by you, so the installer is not the only person reporting the result. Ask whether the proposal includes that test and who will do it.
A contract may promise a negotiated radon level. EPA's example of the question to ask is whether the contractor guarantees 4 pCi/L or below, and for how long. The same guide says levels below 4 pCi/L still pose a risk and in many cases can be reduced. Read any promise before you treat it as part of the price. Plan to retest at least every two years.
Sources: EPA: Consumer's Guide to Radon Reduction (2025, PDF).
4. What to compare besides the total
EPA says a less expensive system may cost more to operate and maintain, may suit the house less well, or may use materials that do not last as long. A higher price is not automatically the better proposal. Compare what is included: proof of the credential the contractor claims, liability insurance and bonding, diagnostic testing, a warning device, a test after installation, and any guarantee.
An extended warranty, a service plan, or a neater pipe route can raise the first invoice. Ask for those as separate lines. These notes are from EPA's guide for homes in the United States. They are not a price for a home in Canada, and they are not a provincial licence. A national listing is not a state license.
Sources: EPA: Consumer's Guide to Radon Reduction (2025, PDF).
Before you accept an estimate
- Which foundation types does this home have, and which system is proposed?
- Are diagnostic tests included, or billed on their own?
- Where will the fan be installed, and who obtains the permits?
- Is the post-installation test included, and who does an independent measurement?
- Does the contract name a guarantee, and for how long?
Find a credentialed provider
Check a mitigator's credential number in the directory, then ask that person for an estimate. This directory records credentials, not prices.
Find providers in your area · Check credentials by state
Testing instructions and requirements depend on the test, building and jurisdiction. Use the linked agency guidance and your qualified professional’s instructions for your situation.