Furnace Smells Like Gas? Emergency Safety Guide for Portland Homes
Natural gas smells like rotten eggs for safety, but any gas smell from your furnace signals a serious problem. Portland homeowners face unique risks from older homes and humid crawlspaces. This guide covers emergency protocols, dangerous causes, and when to call professionals immediately.
IF YOU SMELL STRONG GAS: ACT NOW!
EVACUATE IMMEDIATELY - Get everyone out of the house
DO NOT turn lights on/off, use phone, or start car
CALL 911 from outside or neighbor's phone
CALL NW NATURAL at 800-422-4012 (24/7 emergency)
DO NOT RETURN until cleared by professionals
CALL US for furnace inspection after safety clearance
Licensed NATE-certified technicians • Same-day emergency service • Portland metro coverage
Owner & Lead HVAC Technician
Natural Gas Safety
How to Identify Natural Gas Leaks
Rotten egg smell - NW Natural adds mercaptan odorant for safety detection
Hissing sound - Gas escaping from pipes or connections
Dead plants/grass - Gas prevents oxygen uptake near leaks
White mist/cloud - Cold gas condensing in humid Portland air
Bubbles in water - If leak is near water source
When Gas Smell is Normal (And When It's Not)
Normal Gas Smells:
First 10-30 seconds of furnace startup: As the system purges air from gas lines, you may notice a brief, faint gas smell. This is normal and dissipates quickly as combustion begins.
Relighting pilot light: Standing pilot systems (older furnaces) may have a brief gas smell when manually relighting the pilot. This is normal if it clears within 30 seconds.
Very faint smell near closed furnace door: Some accumulation in the combustion chamber can be normal, especially in humid Portland weather.
Danger Signs That Require Immediate Action:
- Strong, persistent smell that doesn't go away
- Smell present when furnace is off
- Headaches, dizziness, or nausea (carbon monoxide symptoms)
- Hissing sounds from gas lines
- Dead vegetation near gas lines
- Multiple family members feeling ill simultaneously
Portland-Specific Gas Safety Issues
Portland's natural gas comes from NW Natural and serves 95% of homes in the metro area. Our older homes often have iron gas pipes that corrode over time, especially in damp crawlspaces. The region's humidity accelerates corrosion of gas valves and connections. Earthquakes can loosen fittings, and moss/vegetation can block vent pipes.
Cracked Heat Exchanger (EMERGENCY)
A cracked heat exchanger allows carbon monoxide and unburned gas to leak into your home. This is the most dangerous cause of gas smell and requires immediate action. Portland's older furnaces (15-25 years old) are particularly susceptible due to corrosion from our humid climate and metal expansion from temperature changes.
Portland-Proven Fix:
Shut off the furnace immediately, evacuate the home, and call a professional. We perform combustion analysis and camera inspection to confirm. Most cracked exchangers require full furnace replacement ($3,500-$7,500). Never ignore this - carbon monoxide is deadly.
Failed Gas Valve Seal
The gas valve contains internal seals that prevent gas leakage when the valve is closed. Over time, these seals can harden, crack, or wear out, allowing small amounts of natural gas to escape. This is more common in older Portland homes with 1980s-1990s furnaces.
Portland-Proven Fix:
A technician must inspect and replace the gas valve ($300-$600). This is not a DIY repair due to gas line safety requirements. We also check for proper gas pressure while we're there.
Loose Gas Line Connection
Vibration from the blower motor or settling of the home can loosen gas pipe connections. Portland's earthquake activity and older homes with crawlspace installations increase this risk. A hissing sound often accompanies the smell.
Portland-Proven Fix:
Turn off the gas at the meter (or main valve), then call a professional to retighten connections and test for leaks. We use soapy water solution to check for bubbles at all joints. Cost: $150-$300.
Pilot Light Out (Standing Pilot Systems)
Older furnaces with standing pilot lights burn a small flame 24/7. If the pilot goes out due to drafts, dirty thermocouple, or low gas pressure, unburned gas can accumulate. Most Portland homes built after 2000 use electronic ignition, but older homes still have these systems.
Portland-Proven Fix:
Locate the gas valve (usually has OFF-PILOT-ON positions). Turn to OFF, wait 5 minutes, then relight following manufacturer instructions. If it won't stay lit, call professional - likely thermocouple failure ($150-$300).
Incomplete Combustion
Dirty burners, blocked vents, or insufficient air supply can cause incomplete gas burning. This produces carbon monoxide and unburned hydrocarbons that smell like gas. Portland's high humidity can accelerate burner corrosion.
Portland-Proven Fix:
Professional burner cleaning and combustion analysis ($150-$250). We also inspect intake and exhaust vents for blockages from leaves, moss, or bird nests. Annual maintenance prevents this issue.
Venting Issues
Blocked or disconnected vent pipes prevent proper exhaust of combustion gases. High-efficiency furnaces with PVC pipes are especially vulnerable to blockages from Portland's vegetation and weather. Backdrafting can pull exhaust back into the home.
Portland-Proven Fix:
Inspect exterior vent terminations and clear any obstructions. We check for proper venting and may install vent guards or extend pipes above expected snow/moss lines. Cost: $100-$400 depending on extent.
Call Emergency Services If You Notice:
Strong gas smell combined with headaches or dizziness
Gas smell present when furnace is completely off
Hissing sounds from gas pipes or furnace area
Dead plants or vegetation near gas lines
Portland Furnace Gas Smell FAQs
Gas Smell Emergency? Call Efficiency Heating & Cooling Now
Don't take chances with gas smells - our NATE-certified technicians respond to gas emergencies 24/7 across Portland. We'll diagnose the problem safely and recommend the right repairs to protect your family.