Radon and HVAC: What Bay Area Homeowners Should Know

Radon is a naturally occurring radioactive gas that can accumulate in homes. HVAC systems influence how it moves and concentrates.

Understanding Radon

What It Is Radon is a radioactive gas produced by uranium decay in soil. It enters homes through: - Cracks in foundations - Gaps around pipes - Sump pits - Concrete block walls

Health Risk Radon is the second leading cause of lung cancer after smoking. Risk increases with: - Higher concentrations - Longer exposure - Smoking combined with radon exposure

Bay Area Radon Levels

EPA Zone Classification Most Bay Area counties are Zone 2 (moderate potential) or Zone 3 (low potential). However: - Levels vary by specific location - Some homes in "low" areas have high radon - Testing is the only way to know

Testing Is Simple - Short-term test kits: $15-30 - Long-term tests give more accurate picture - Professional testing available

How HVAC Affects Radon

Negative Pressure HVAC systems can create negative pressure that draws radon in: - Return air leaks in basement/crawlspace - Unbalanced duct systems - Exhaust fans without makeup air

Air Distribution Your HVAC system distributes air throughout the home, potentially spreading radon that enters in one area.

Positive Effects Properly functioning HVAC can dilute radon through air exchange and distribution.

HVAC Considerations for High Radon Homes

Duct Sealing Seal ducts in unconditioned spaces to prevent drawing in soil gases.

Balanced Systems Ensure return and supply are balanced to minimize negative pressure.

Fresh Air Intake Adding fresh air to the system dilutes indoor pollutants including radon.

Radon Mitigation

If Testing Shows High Levels Professional mitigation systems: - Sub-slab depressurization (most common) - Soil suction - Positive pressurization - Heat recovery ventilation

HVAC Integration Mitigation systems should be coordinated with HVAC: - Maintain proper pressure relationships - Consider combined air quality approaches - Ensure systems don't work against each other

Action Steps

1. Test your home (especially lower levels) 2. If elevated, retest to confirm 3. If confirmed, hire certified mitigator 4. Address HVAC considerations as part of mitigation

Radon is fixable. Testing is the first step.