Radon Warranty

Radon Warranties, Post-Mitigation Testing, and Long-Term Performance

A radon warranty should answer more than how long the fan is covered. It should explain the performance target, when the warranty begins, which components and labor are included, what the owner must do, what conditions are excluded, and how an elevated follow-up result will be handled.

The written proposal and warranty control. This website summary helps customers understand the categories, but it does not replace the signed documents for a specific system.

Request Current Warranty Terms

Drennen Warranty Summary

Performance Target

For applicable Drennen-installed systems, the current written warranty describes maintaining an annual-average radon level below 4.0 pCi/L, subject to its terms, exclusions, testing obligations, and the completed system design.

Installation-Performance Term

The current Drennen document describes a 20-year installation-performance warranty beginning from a completed post-mitigation test result of 3.99 pCi/L or less, subject to the written conditions.

Fan Warranty

The fan carries the manufacturer warranty stated in the project documents. Drennen current materials commonly identify a five-year manufacturer fan warranty.

Retesting Obligation

The current Drennen warranty requires the owner to test at least every two years using approved follow-up protocol and retain the records to maintain the performance warranty.

Always read the current signed warranty. Structural changes, abuse, settling, natural hazards, third-party alterations, ground-water or external-drain conditions, components installed by others, and other listed circumstances may limit or void coverage.

Five Different Protections People Commonly Confuse

Initial Post-Mitigation Result

A short-term measurement documents the indoor concentration after the new system has operated under the applicable test conditions. It is proof of initial performance, not a promise that the level can never change.

Performance Warranty

A contractor commitment tied to a radon target and written conditions. It may require periodic testing and excludes conditions outside the contractor control.

Installation or Workmanship Coverage

Addresses qualifying installation defects or specified labor. Read the term, transferability, response process, and exclusions.

Manufacturer Fan Warranty

Covers qualifying defects in the fan under the manufacturer terms. It may not cover diagnosis, shipping, labor, electrical issues, misuse, water, or a system-design change.

Homeowners Insurance

Insurance is separate from the contractor and manufacturer warranties and should not be assumed to cover routine fan failure, radon levels, maintenance, or mitigation.

Why Post-Mitigation Testing Matters

It confirms the initial indoor result rather than assuming the fan and pipe are enough
It establishes the baseline for the warranty and future comparison
It can reveal a disconnected foundation zone, membrane leak, inadequate communication, or unusual test condition
It provides documentation for the owner, buyer, seller, landlord, lender, or facility manager
It guides additional diagnostics when the first result remains elevated

Why Retesting Every Two Years Matters

A mitigation system can continue to sound and show pressure even when indoor concentrations have changed. Fans age, soil moisture changes, membranes are disturbed, buildings settle, foundations are altered, HVAC and ventilation change, and additions can create new zones. Periodic testing is the direct check on indoor concentration.

Retest Sooner After These Events

Fan replacement, repair, reroute, or system modification
Basement finishing, additions, new windows, weatherization, or major air-sealing
Foundation repair, waterproofing, sump work, drain changes, or significant new cracks
HVAC, exhaust, ventilation, or combustion-equipment changes
Crawl-space membrane damage or work by another trade
Earthwork, blasting, severe flooding, sinkholes, or other significant ground disturbance
A real estate transaction or a change in use of the lowest level

What to Keep With the Property

Original test and all follow-up results
Proposal, contract, change orders, warranty, and paid invoice
Responsible Colorado license information and national certification information
System photographs and route or as-built information
Fan make, model, serial number, install date, and manufacturer warranty
Normal manometer or monitor reading and alarm instructions
Service history and every two-year test record

What Happens if a Follow-Up Test Is Elevated

1
Verify the test
Review device, placement, duration, closed-building conditions, unusual weather or operation, and whether the test followed the applicable protocol.
2
Check the system
Confirm fan power, pressure, alarm, piping, couplings, condensate, discharge, crawl membrane, and any recent building changes.
3
Diagnose foundation communication
The licensed professional evaluates whether every intended slab or crawl zone remains under effective suction.
4
Apply the written warranty
Coverage and corrective work are determined from the signed warranty, system history, testing records, exclusions, and responsible components.
5
Retest after correction
Document the result and preserve the new report with the system records.

Frequently Asked Questions

Know What the Written Promise Actually Covers

Ask Drennen for the current proposal and warranty before comparing bids. We will explain the performance target, post-test, fan coverage, owner responsibilities, exclusions, and service process.

Request Current Radon Warranty Information

Warranty language last reviewed for this page in July 2026. The signed project documents control. Do not publish or rely on this summary until the office confirms the current warranty version.

Drennen Custom Contracting | Serving Fort Collins and Northern Colorado | 970-482-9100 | [email protected]