Radon systems occupy a narrow price band as home repairs go, but quotes still differ house to house — and the differences are legible. The fan and pipe are commodities; what you are pricing is the labor of collecting soil gas under your particular foundation and walking it legally above your particular roof.
Foundation layout
One continuous slab over gravel: one suction point, the easy case. Additions on separate slabs, split-levels, and basement-plus-crawl combinations — all common in Dane County housing — can each demand their own collection point, and each point is labor.
What is under the slab matters equally: coarse fill shares suction generously; dense fill fights it and may need a bigger pit or stronger fan.
The pipe's path
Interior routes — up through a closet or garage into the attic, fan in unconditioned space, short roof penetration — hide the system and shelter the fan from Wisconsin winters. Exterior wall runs trade visibility for simpler installation. Long horizontal runs, finished ceilings, and rooflines that force a taller discharge all add hours.
Finished space
A finished Madison basement means drywall, trim, and carpet between the installer and the slab — the same system costs more installed around finishes than through an open floor. Planning to finish later? Mitigate first; the order of operations is worth real money.
What the quote should include
Sealing of cracks and the sump, the manometer, system labeling, and a post-installation test with a number the installer commits to in writing — below 4, usually well below. In Wisconsin, ask for the state radon proficiency credential too; the pros have it ready.
Comparing two quotes fairly
Line up scope before price: suction points, pipe route, fan placement, sealing, and the written post-test commitment. Two 'radon system' quotes hundreds apart usually differ in those five lines, not in generosity.
The cheapest legitimate system is the one installed before the basement gets finished — order of operations is the biggest cost lever a homeowner controls.
