Once a radon mitigation system is installed, the big question shifts from "what did this cost" to "what does this cost me every month." The short version: the ongoing cost is almost entirely electricity for a small fan, and it's modest -- but there are a few real maintenance and health-threshold facts worth knowing so you actually understand what you're paying to keep at bay.
How much does it cost per month to run a radon mitigation system?
Running an active sub-slab depressurization (ASD) system typically adds only a small amount to a monthly electric bill, because the in-line fan is low-wattage and there's usually no separate service fee unless you've signed up for an optional annual maintenance or monitoring plan. For most Minnesota households, the ongoing cost is the electricity draw and, eventually, a fan replacement every several years.
There isn't a single fixed dollar figure that applies to every home, since it depends on your fan model, your local electricity rate, and how long the duct run is. The way to get an exact number for your own house is to check the fan's wattage (usually on a sticker on the fan housing) and multiply by your utility's per-kWh rate over 730 hours a month, since the fan runs continuously.
How much electricity does a radon mitigation fan use?
A typical residential radon fan, such as models made by RadonAway or Fantech that are commonly installed in Minnesota homes, draws roughly the same power as a couple of light bulbs running around the clock. Longer or more restrictive duct runs, more elbows, or a larger sub-slab area can push the fan toward the higher end of that range because it has to work harder to maintain suction.
Because the fan never cycles off -- it needs to run 24/7 to keep the negative pressure field under the slab consistent -- the electrical cost is steady rather than seasonal. If your electric bill jumps noticeably after mitigation, it's worth having the licensed operators in our network check whether the wrong fan size was installed for your home's foundation.
What maintenance does an active sub-slab depressurization system need?
An ASD system needs almost no hands-on maintenance beyond a monthly glance at the U-tube manometer gauge mounted on the vent pipe, which visually shows whether the fan is still pulling suction correctly. Beyond that, radon fans typically last five to ten years before needing replacement, and the home should be retested periodically to confirm the system is still working.
- Check the manometer gauge monthly -- if the liquid level looks even (no differential), the fan may have failed.
- Keep the vent pipe's roof or wall termination clear of snow, ice buildup, or debris, which matters for homes in Duluth, St. Cloud, and other parts of Minnesota with heavy winter accumulation.
- Retest with a radon kit or continuous monitor roughly every two years, and always after any foundation cracks, remodeling, or new sump pit work, per the EPA's A Citizen's Guide to Radon.
What radon levels are considered harmful or dangerous?
The U.S. Environmental Protection Agency recommends fixing a home if a test result comes back at 4 picocuries per liter (pCi/L) or higher, and suggests homeowners consider mitigation for results between 2 and 4 pCi/L. There is no scientifically established "safe" level of radon -- risk rises with both the concentration measured and the amount of time spent in that space.
Minnesota is worth taking seriously on this front specifically: the entire state falls into the EPA's highest radon potential category (Zone 1) on the agency's Map of Radon Zones, meaning predicted average indoor screening levels above the 4 pCi/L action level are common in counties across the state, including Hennepin County, Ramsey County, Dakota County, and Stearns County.
How bad is radon exposure over time?
Radon is recognized by the EPA as the second leading cause of lung cancer in the United States after smoking, and the health risk from long-term exposure accumulates over years rather than showing up after a single high reading. A finished basement bedroom or home office in Minneapolis, St. Paul, Rochester, or Eden Prairie that sees elevated radon and heavy daily use carries more cumulative risk than a rarely used crawlspace with the same reading.
The Minnesota Department of Health's radon program tracks this risk statewide and, under Minnesota Statutes § 144.496, requires radon measurement and mitigation professionals to be licensed by MDH -- a real, checkable safeguard worth confirming before hiring anyone, separate from anything a contractor tells you about their own experience.
Does the monthly cost change with Minnesota's seasons?
The fan's electricity draw stays essentially flat year-round since it runs continuously, but Minnesota's cold winters seal basements tighter and increase the "stack effect" that pulls soil gas indoors, so some homeowners notice radon levels -- and how hard the system seems to be working -- become more apparent in winter. That seasonal shift affects indoor air quality more than it affects the electric bill.
If you're still comparing installers rather than living with a system already in place, it's worth reading how to evaluate the best radon mitigation near me in Minnesota, what the upfront cost of radon mitigation in Minnesota typically looks like, and how an ASD system actually works before you sign anything.
This article is for general homeowner education and isn't a substitute for a professional radon test or inspection of your specific system. Radon levels, fan performance, and code requirements vary by property and municipality -- confirm licensing status and current local requirements with the Minnesota Department of Health before hiring anyone. All field work referenced here is performed by independent licensed operators, not by minnesotaradonexperts.com directly.