What does a radon fan cost to run each month in a Knoxville home?

Why the fan runs 24/7 after a Knox County mitigation install

Active soil depressurization only works while the fan pulls. Soil gas under a Knoxville slab or crawl does not take weekends off. When living-space levels were high enough to justify mitigation, the design goal is continuous suction and outdoor exhaust, not a timer.

Turning the fan off to "save a few dollars" puts the house back toward the conditions that failed the test. Operating cost is real. Leaving a confirmed Zone 1 house high is the larger risk conversation. For what drives install cost before the meter spins, see mitigation cost in Knoxville and the mitigation service page.

Read the nameplate: typical equipment watts are model-specific

Residential radon fans are not one watt rating. Public reference sheets, including the Minnesota Department of Health mitigation energy-cost PDF, show common models spanning roughly 20 W on the low end to well over 100 W depending on design and duty. That range is market context, not a promise for your house.

Find the watts on:

• The fan nameplate or sticker.
• The install packet or proposal that named the model.
• Manufacturer literature for that exact model number.

Do not use a forum average and call it your bill. Model and static pressure both matter.

Method reference (market how-to, not a local bid): MN Health Calculating Energy Costs for Mitigation Systems.

Simple estimate formula

Use this arithmetic with your own numbers:

1. Watts from the nameplate (example placeholder only: W).
2. Hours per day: 24 for a continuous fan.
3. Days in the period: 30 for a rough month, or 365 for a year.
4. Convert watt-hours to kilowatt-hours: watts × hours × days ÷ 1000.
5. Multiply by your utility rate in dollars per kWh.

Written out for a month:

Monthly kWh ≈ watts × 24 × 30 ÷ 1000

Monthly $ ≈ monthly kWh × your $/kWh

For a year:

Annual kWh ≈ watts × 24 × 365 ÷ 1000

Annual $ ≈ annual kWh × your $/kWh

Pull the kWh rate from a recent KUB (or other local utility) bill. Rates change. The formula stays the same. We will not invent a Knoxville monthly dollar figure on this page, because without your watts and your rate any number would be a guess.

What changes the real number

Nameplate watts are the starting point. Actual draw can shift with:

• Static pressure under the slab or membrane (tighter soils and longer runs can change how hard the fan works).
• Duct layout (length, elbows, pipe diameter, discharge height).
• Fan model and age (replacements are not always the same watt rating as the original).
• Utility rate (tier changes, seasonal adjustments, provider differences outside KUB territory).

Ask for the model rating at install and keep it with the manometer reading and post-mitigation retest. That packet answers operating-cost questions later without forum folklore.

Cost vs leaving a high Zone 1 result unfixed

Operating cost is one line on a long decision. Knox County Zone 1 potential means elevated indoor levels show up often enough that many owners mitigate after a clear test. Electricity for a continuous fan is ongoing. Breathing an unfixed high result is also ongoing.

If you are weighing dollars, put three numbers side by side: install scope, estimated fan kWh from the formula above, and the living-space radon number you already have. Then schedule a consult instead of stalling on a myth that "fans cost a fortune." Higher watt ratings usually mean more draw, but actual use also follows airflow and pressure. Ask for the model at install.

High test in Knoxville and weighing operating cost vs risk? Call (865) 420-6136 for mitigation next steps.