The model turns four visible home characteristics and, if supplied, a ZIP-based state price factor into a broad professional-installation planning range. It is intended to help a homeowner prepare for quotes. It does not select a system, predict radon reduction, or replace an inspection.
The midpoint calculation
The calculator begins with a $1,150 base installation allowance and adds the following adjustments:
| Input | Current adjustment |
|---|---|
| Home size | $0.18 for each sq ft above 1,200 sq ft |
| Slab-on-grade | +$100 |
| Basement | +$250 |
| Crawl space | +$500 |
| Mixed foundation | +$750 |
| One story | +$0 |
| Two stories | +$225 |
| Three or more stories | +$450 |
| Simple exterior pipe route | +$0 |
| Standard pipe route | +$250 |
| Complex or concealed route | +$650 |
| Optional ZIP adjustment | Multiply by the state’s 2024 BEA all-items regional price parity divided by 100 |
The midpoint is rounded to the nearest $50. The displayed low end is 78% of the midpoint, with a minimum of $900. The high end is 134% of the midpoint. Both ends are also rounded to the nearest $50.
How the ZIP adjustment works
When you apply a ZIP code, the calculator looks up its city and state, then multiplies the national midpoint by that state’s 2024 Bureau of Economic Analysis all-items regional price parity. For example, an index of 105 becomes a 1.05 multiplier, while an index of 92 becomes a 0.92 multiplier.
This is a broad state price-level adjustment, not a database of radon contractor quotes. It cannot capture differences between cities, contractor schedules, permits, travel, or unusual site conditions. The BEA released the current 2024 data on February 19, 2026. The postal-code lookup service is contacted only when you select “Apply ZIP.”
Worked example
Without a ZIP adjustment, a 1,800-square-foot, two-story basement home with a standard pipe route is $1,150 base + $108 size + $250 foundation + $225 stories + $250 routing. The raw midpoint is $1,983, which rounds to $2,000. The displayed planning range rounds to $1,550–$2,650.
Why the radon level does not change the price
The test result is displayed so the homeowner can compare it with EPA action guidance. It does not change the estimate because a radon number does not reveal sub-slab airflow, foundation zones, pipe access, or the fan needed for a specific design. Those questions require inspection and diagnostic work.
What the model does not know
- Actual local contractor rates, travel charges, demand, or sales tax.
- Soil permeability and pressure-field extension beneath the home.
- The number of slabs, footings, additions, and isolated foundation zones.
- Permit, inspection, and electrical requirements.
- Crawl-space membrane area, piers, moisture, and working clearance.
- Finish repairs, asbestos, inaccessible construction, or other concealed conditions.
- Whether the home needs a less common mitigation method.
Sources and editorial standard
The model’s structure follows EPA guidance that cost varies with the size and design of the home and the reduction method required. Technical descriptions use the EPA Consumer’s Guide to Radon Reduction. Health statements and action thresholds are linked to EPA or CDC pages wherever they appear.
The dollar allowances are our own budgeting assumptions. The optional regional adjustment uses the latest available BEA state price parity. These model outputs should be checked against written local proposals. We revise the model when authoritative cost guidance changes or when better verified pricing data becomes available.