Carbon monoxide is invisible, odorless, tasteless — and lethal at concentrations that develop faster than most homeowners realize. CO exposure symptoms (headache, nausea, confusion, fatigue) can mimic flu, food poisoning, or ordinary tiredness, and CO poisoning victims often don’t recognize what’s happening until they’re unable to respond. PolarCore’s CO testing service combines home-wide CO measurement with combustion analysis at every gas-fired appliance to identify sources, verify safe combustion, and confirm venting integrity. Testing uses the same Bacharach Fyrite Insight combustion analyzer used on every furnace service call, plus personal CO monitors and battery-powered CO alarms for ambient measurement. Testing is available on demand after any CO alarm activation, as part of annual furnace tune-ups, and as pre-purchase inspection for homes with combustion appliances.
If a residential CO alarm activates:
CO alarms activate at specific concentration and time thresholds (typically 70 ppm for 60–240 minutes, 150 ppm for 10–50 minutes, or 400 ppm for 4–15 minutes per UL 2034 standard). An alarm activation means CO has been building for some time; the concentrations that trigger alarms are already at levels that produce symptoms in vulnerable individuals.
Primary heat exchanger cracks allow combustion products (including CO) to enter the supply airstream and circulate through the house. Diagnostic: borescope inspection through burner ports, combined with combustion analysis showing elevated CO or unusual O⊂2 patterns at the flue. Repair: heat exchanger replacement (under warranty $985–$1,485 labor only) or full furnace replacement if out of warranty.
Bird nests, debris, collapsed liner sections, or downdraft conditions can block combustion product venting and force flue gases into the house. Common on masonry chimney installations serving 80% AFUE furnaces or water heaters. Diagnostic: visual inspection of chimney top and flue, draft measurement at the appliance. Remediation: chimney sweep, liner repair, or venting reconfiguration.
Sealed combustion appliances (95%+ AFUE furnaces with sidewall PVC venting) provide their own combustion air. Non-sealed appliances (80% AFUE furnaces, gas water heaters, gas dryers in older installations) require adequate combustion air from the mechanical room. Airtight construction of newer homes can starve combustion air from these older appliances, producing incomplete combustion and elevated CO. Solution: dedicated combustion air supply, or replacement with sealed combustion equipment.
Standard atmospheric-vent gas water heaters (through a masonry chimney or B-vent) share venting concerns with older furnaces. Backdrafting during appliance ignition can spill combustion products into the house. Diagnostic: combustion analysis at the water heater flue, draft measurement at the draft diverter. Remediation: chimney evaluation, venting reconfiguration, or replacement with power-vent or direct-vent equipment.
LP furnaces and water heaters running with manifold pressure outside 10″WC specification can produce incomplete combustion and elevated CO. Diagnostic: manometer verification against specification. Remediation: LP regulator adjustment or replacement.
Attached garage vehicle exhaust can enter the house through connecting doors, air handler intake, or attic pathways. Common in homes with attached garages, particularly during vehicle warm-up in winter. Prevention: never idle vehicles in attached garages, verify tight seal on connecting doors.
Per manufacturer guidance and Missouri State Fire Marshal recommendations:
CO alarm service life is typically 7–10 years; alarms should be replaced on manufacturer recommendation regardless of test button function.
CO testing and alarm response scheduling runs through the Corona Road office in southwest Columbia. Call (573) 615-6659 for service or post-alarm equipment evaluation. Emergency dispatch is available 24/7 for CO alarm response.