What to Expect After Your Radon Mitigation System Is Installed

The day your radon mitigation system is installed is a significant one. You have tested your home, received an elevated result, made the decision to act, and had a certified professional complete the installation. The work is done and the system is running. What happens next is something many homeowners have questions about but rarely think to ask before the technician leaves. This post answers those questions — what the days, weeks, and months after installation actually look like, and how you know the system is doing its job.

The Immediate Post-Installation Period

The first thing most homeowners notice after installation is that the system is quieter than they expected. A properly installed radon mitigation fan running in an attic, garage, or exterior location produces a low, steady hum that is typically inaudible from the main living areas of the home. If you can hear the fan clearly from your kitchen or living room, that is worth mentioning to your installer — either the fan placement allows more sound transmission than it should, or the fan itself warrants a closer look.

The second thing to check is the manometer — the colored liquid indicator mounted on the visible section of pipe inside your home, usually in the basement. As we described in our post on how mitigation systems work, the manometer shows at a glance whether the system is creating the pressure differential it is designed to produce. With the fan running, the liquid should be visibly displaced to one side of the U-shaped tube. If the liquid sits level, the system is not functioning correctly and your installer needs to be contacted.

Take a moment on installation day to understand what your manometer looks like when the system is operating normally. That baseline observation is your reference point for every future check.

The Post-Installation Radon Test

This is the most important step in the immediate post-installation period and one that should not be skipped. Installing a mitigation system reduces radon levels in the vast majority of homes, but the only way to confirm that your specific system is performing as designed — and to know the actual pCi/L level your family is now living with — is to test.

The EPA recommends waiting at least 24 hours after installation before conducting a post-mitigation test, allowing the system to reach stable operating conditions. Most certified professionals recommend a short-term test of 48 hours or more to get a reliable result. The test follows the same professional process described in our post on what happens during a professional radon test — same placement protocols, same closed-house conditions, same laboratory analysis.

What you are looking for in the post-mitigation result is not simply a number below 4 pCi/L. As we covered in our post on understanding radon levels, the goal of a well-designed mitigation system is to bring levels as low as reasonably achievable — ideally below 2 pCi/L and in many cases approaching the low background levels found in outdoor air. A post-mitigation result of 3.8 pCi/L is technically below the action level but should prompt a conversation with your installer about whether the system is optimally designed for your home.

If the post-mitigation test comes back higher than expected — above 4 pCi/L or only marginally reduced from the pre-installation level — your installer needs to assess the system. Possible explanations include insufficient suction reach across the sub-slab area, a fan that is undersized for the conditions, or additional radon entry points that the system is not addressing. A quality installer stands behind their work and will diagnose and address performance issues without treating them as the homeowner's problem.

Life With the System Running

Once the post-mitigation test confirms the system is performing well, life with a mitigation system in place is largely unremarkable — which is exactly as it should be. The fan runs continuously in the background. The manometer shows the system is working. The air in your home is measurably safer than it was before installation. There is nothing to actively manage on a daily basis.

A few practical points about living with the system are worth knowing.

The fan runs on electricity continuously, adding a modest amount to your monthly energy bill — typically equivalent to running a low-wattage light bulb around the clock. This is a small and fixed ongoing cost that most homeowners find entirely acceptable relative to what the system provides.

The pipe that routes through or along your home becomes a permanent fixture. Interior pipe runs are typically painted to match the wall or finished to blend with the basement space. Exterior pipe runs are weather-resistant and designed to last. Neither should require any attention under normal circumstances.

Normal home activities — running your HVAC system, using exhaust fans briefly, doing laundry, cooking — do not affect the mitigation system's operation. The system is designed to function alongside normal home use and is not disrupted by the everyday activities that happen in a household.

When to Check the Manometer

You do not need to inspect your mitigation system daily, but building a quick manometer check into a periodic home maintenance routine is a simple habit worth developing. Once a month is more than sufficient for most homeowners — a glance at the colored liquid indicator on your way through the basement tells you immediately whether the system is operating normally.

If the liquid ever appears level rather than displaced, that is your signal to contact your mitigation professional. A level manometer indicates the fan may have stopped running, lost suction, or developed a problem worth investigating. Catching this promptly matters because a non-functioning system means your radon levels are no longer being controlled.

The Two-Year Retest

The post-installation test confirms the system worked immediately after installation. The two-year retest confirms it is still working as your home ages and conditions evolve. Foundations continue to settle over time. Minor cracks develop. Seasonal changes affect how air moves through the home. A retest every two years is the standard recommendation, and it is a straightforward way to confirm that the protection you invested in continues to deliver.

If a two-year retest comes back with levels noticeably higher than the post-installation result, that is useful information. It may indicate the fan is losing efficiency and approaching the end of its service life, that a new entry point has developed that the existing system is not fully addressing, or that something about the home's conditions has changed in a way worth investigating. None of these scenarios are cause for alarm — they are manageable situations that a certified radon professional can assess and address.

The Bigger Picture

Having a mitigation system installed and confirmed through post-installation testing puts your home in a genuinely better position than the majority of Michigan homes. Most homes in this region have never been tested, let alone mitigated. Your family is breathing air that has been measured, addressed, and verified — a standard of indoor air quality that far too few Michigan homeowners have established.

The system running quietly in the background is not something most families think about once it is in place and confirmed. That is exactly how it should work. The peace of mind it represents is real, even when it is invisible.

At All Michigan Mitigation, we stand behind every system we install with post-installation support and the expertise to address any performance questions that arise. Radon testing and mitigation is everything we do, and that commitment extends beyond installation day.

Visit us at allmichiganmitigation.com to learn more about what the mitigation process involves or to schedule a consultation for your home.

All Michigan Mitigation is a West Michigan radon testing and mitigation company dedicated exclusively to helping homeowners understand and eliminate radon risk in their homes.