Carbon Monoxide Testing Salt Lake City | CO Safety

Carbon Monoxide Testing in Salt Lake County

December 18, 2024. A family in West Valley City — the homeowner is Yolanda M., the same customer whose Bryant AC evaporator coil leak story appears on the refrigerant recharge page — called us with a different concern that turned out to be far more serious. Yolanda’s two teenage sons had been waking up with headaches and fatigue for several weeks. Her husband had been feeling “off” each morning, with symptoms that improved within hours of leaving for work. Yolanda herself had noticed strange dizziness while making breakfast. The family had a CO detector but it wasn’t alarming. Dakota Whitfield arrived at 8:42 a.m. with a calibrated Bacharach Monoxor III electrochemical CO meter and a Testo 320 combustion analyzer. Initial ambient reading in the kitchen: 27 ppm CO at standing height, 31 ppm at the cook surface. Below the 70 ppm alarm threshold required for CO detectors per UL 2034, but well above the 9 ppm WHO recommended exposure limit and clearly explaining the family’s symptoms. Investigation traced the source: Yolanda’s 1998 Magic Chef gas range had a partially failed primary burner with incomplete combustion producing CO at 580 ppm at the burner surface, dispersing through the kitchen during morning cooking and persisting in lower concentrations for hours afterward. The CO detector wasn’t malfunctioning — the family’s exposure was real but below the detector’s design alarm threshold. Yolanda’s family relocated the kids to her sister’s house that night while she arranged immediate gas range replacement. We documented the CO measurements, flagged the gas range as the source, and provided written records for her insurance claim and the new range installation. Chronic CO exposure at 15-50 ppm is a real and underdiagnosed health concern in homes with aging gas equipment. Detectors catch the acute danger (above 70 ppm sustained); they don’t reliably catch the chronic exposure that affects sleep, cognition, and overall wellness.

Carbon monoxide is a colorless, odorless gas produced by incomplete combustion of any carbon-containing fuel — natural gas, propane, fuel oil, wood, gasoline, charcoal, kerosene. The CDC reports approximately 420 unintentional non-fire CO deaths annually in the United States, plus approximately 50,000 emergency department visits. A larger number of cases — chronic low-level exposure that produces flu-like symptoms, sleep disturbance, and cognitive impairment — go undiagnosed because standard CO detectors are designed to catch acute danger rather than chronic exposure. Professional CO testing addresses this gap, particularly in homes with gas appliances older than 10 years, homes with attached garages, homes with multiple combustion sources, or homes where occupants experience unexplained symptoms that improve when away from home. For broader IAQ context see the indoor air quality services hub.

CO Exposure Limits — What the Numbers Mean

0-9 ppm (background):
Normal urban background level. Outdoor air may run 0-3 ppm in non-traffic conditions; up to 9 ppm near busy roads. Indoor air should match outdoor in this range. EPA NAAQS 8-hour outdoor limit: 9 ppm.
10-35 ppm (elevated, chronic concern):
Significantly above normal. WHO recommends limiting exposure to 25 ppm over 1 hour. Chronic exposure in this range causes: headaches, fatigue, dizziness, nausea, cognitive impairment, sleep disturbance, exacerbation of cardiovascular conditions. Particularly concerning for children, elderly, pregnant women, people with heart or lung conditions.
36-69 ppm (high, requires immediate action):
Source identification and equipment shutdown required. Acute symptoms within hours of exposure. UL 2034 standard CO detectors do not alarm at this range, but professional measurement detects the problem and prompts action.
70-149 ppm (alarming, acute danger):
UL 2034 CO detectors must alarm within 60-240 minutes. Symptoms develop within 1-2 hours: severe headache, nausea, confusion, exhaustion. Source must be identified and equipment shut down immediately.
150-400 ppm (severe, life-threatening):
UL 2034 CO detectors must alarm within 10-50 minutes. Symptoms develop rapidly: severe headache, nausea, vomiting, loss of consciousness within hours. Immediate evacuation required.
400+ ppm (extreme):
UL 2034 CO detectors must alarm within 4-15 minutes. Loss of consciousness within an hour; death possible within 2-3 hours. Immediate evacuation required; 911 + Salt Lake City Fire Department response.

What CO Detectors Catch (And What They Miss)

Residential CO detectors are designed to UL Standard 2034 (United States) requirements:

What UL 2034 requires:
Detector must alarm at 70 ppm sustained for 1-4 hours, 150 ppm sustained for 10-50 minutes, or 400 ppm sustained for 4-15 minutes. Lower concentrations are below the regulated alarm threshold.
What this means in practice:
A home with sustained 30-50 ppm CO concentrations will NOT trigger any standard CO detector, even though occupants are experiencing chronic exposure that affects health. The detector is functioning correctly; the design simply doesn’t address chronic low-level exposure.
Better detector options:
Some commercial-grade detectors (Honeywell BW Solo, Industrial Scientific Ventis Pro 5, Kidde Nighthawk RV with digital display) provide real-time digital readout at lower concentrations. These show 1-99 ppm in real time, allowing occupants to see elevated levels even below the alarm threshold. We recommend digital display detectors for homes with gas equipment older than 10 years or for households with health-sensitive occupants.
Detector lifespan:
Most UL 2034 detectors have 5-10 year operating life. The electrochemical sensor degrades over time even when the unit appears to function. Replace per manufacturer recommendation; many newer units have a “replace by” date printed on the housing.
Detector placement (UL 2034 + good practice):
One detector on each floor of the home. One detector near sleeping areas. Specific bedroom placement if any single bedroom is more than 30 feet from the nearest detector. Detector placement at standing-occupant height is general guidance; older units placed near ceilings work but detect CO that’s already mixed throughout the room. Mid-wall height (4-6 feet above floor) catches developing CO concentration faster.

Common CO Sources in Salt Lake County Homes

Gas furnaces (highest single-source risk):
Cracked heat exchangers (covered in detail on the heat exchanger repair page) release combustion gases into supply air. Improperly altitude-derated equipment (running rich at our 4,226 ft elevation) produces excess CO. Blocked venting backs combustion gases into the home. We test combustion CO during every annual furnace tune-up.
Gas water heaters:
Atmospheric-vented water heaters (most pre-2018 installations) can backdraft when negative pressure develops in the equipment room. CO production from water heater combustion typically lower than furnace, but exhaust events can produce significant indoor CO. Power-vented water heaters (most current installations) have lower backdraft risk.
Gas ranges and cooktops:
The Yolanda M. case at the top of this page. Aging burners with partial primary air blockage produce significant CO during operation. Newer ranges (post-2015 with electronic ignition and proper burner geometry) much lower risk than older equipment. Operating gas ranges in poorly ventilated kitchens significantly increases exposure regardless of burner condition.
Gas fireplaces:
Direct-vent gas fireplaces (modern installations) properly vent combustion outside. Vent-free gas fireplaces (sold in some areas though prohibited in Utah residential construction) release combustion products into the home, including CO at low levels during operation. Older B-vent gas fireplaces can backdraft like atmospheric water heaters.
Attached garage CO infiltration:
Idling vehicles in garages produce significant CO that infiltrates living spaces through the wall between the garage and home. Even briefly warming up a car in winter can introduce CO to the home; idling for extended periods (working on a vehicle, electric vehicle conditioning on a charger) creates serious exposure risk.
Wood stoves and pellet stoves:
Properly-installed and maintained units vent combustion outside. Issues arise from chimney creosote buildup (restricts venting), backdraft during cold weather (high pressure outside or negative pressure inside), and operator error (closing damper too early when starting fires). Less common in Salt Lake County than in mountain communities, but still present.
Power generators (emergency use):
Operating generators in attached garages, in basements, or near open windows produces severe CO exposure within minutes. NEVER operate generators inside any structure. PCAPS inversion events that cause power outages have caused multiple CO poisoning incidents in our service area over the years.
Charcoal grills and outdoor heaters:
Operating outdoor combustion equipment indoors during cold weather is consistently among the leading causes of CO poisoning deaths nationally. Salt Lake’s cold winters drive some people to bring these indoors despite warnings.

When to Schedule Professional CO Testing

Annual baseline testing.
Included in every fall furnace tune-up (see the furnace tune-up page for the 19-point checklist that includes combustion analysis and ambient CO measurement). Establishes baseline for the home’s CO levels and identifies any equipment-source issues before symptoms develop.
Unexplained symptoms.
Household members experiencing fatigue, headaches, dizziness, nausea, sleep disturbance, or cognitive issues that improve when away from home — particularly if multiple household members are affected, or if symptoms worsen during periods of heavy combustion equipment use (cold weather, holiday cooking, fireplace use).
Detector activation.
If a CO detector alarms, do not assume false alarm. Evacuate the home, call 911, and arrange professional CO testing before re-occupying. Detector activation indicates levels above 70 ppm (potentially much higher); source identification is required before safe re-occupation.
Pre-purchase due diligence.
Buying a home with multiple combustion appliances, older equipment, or attached garage. Professional CO testing during the inspection period documents baseline conditions before purchase.
New equipment commissioning.
After furnace, water heater, or other gas appliance installation, professional CO testing verifies proper combustion and venting. Standard included in our installation services.
Renovation or sealing projects.
Air sealing improvements (insulation upgrades, window replacement, weatherization) reduce natural ventilation rates and can elevate indoor CO concentrations from existing equipment that was acceptable in leakier construction. Professional CO testing after weatherization verifies safe operating conditions.
Equipment alterations.
If you’ve had work done by unfamiliar contractors (cleaning, repair, modification), have professional CO testing performed afterward to verify no inadvertent changes affected combustion or venting.

Our CO Testing Process

  1. Initial consultation. Symptoms inventory, recent changes (equipment service, weatherization, new appliances), specific concerns. Review of existing CO detector placements and ages.
  2. Equipment-specific combustion analysis. Testo 320 combustion analyzer measurements at each gas appliance during operation. Records: CO (ppm air-free), O₂ (%), CO₂ (%), flue gas temperature, combustion efficiency. Compared against manufacturer spec and our action thresholds.
  3. Ambient CO measurement throughout home. Bacharach Monoxor III electrochemical CO meter readings at multiple locations: kitchen, each bedroom, basement, equipment room, near each combustion appliance, in attached garage (if applicable). Measurements taken during normal household operation (heating cycle, range use if applicable).
  4. Equipment inspection. Visual inspection of venting (chimney condition, vent pipe integrity, termination clearances). Equipment room ventilation (combustion air supply adequacy). Detection of any installation issues that may contribute to CO problems.
  5. Documentation. All readings recorded with location, time, and equipment status. Written report delivered with measurements, findings, and recommendations.
  6. Action plan. Based on findings:
    • If no issues found: documentation of baseline conditions for future reference
    • If equipment issues found: repair recommendations with cost estimates
    • If serious safety issues found: equipment shutdown and red-tag, immediate replacement quotes provided
    • If exposure issues found from non-equipment sources (garage CO, range use patterns): behavior modification recommendations and ventilation upgrades
  7. Detector recommendations. Review of existing detector placements, ages, types. Recommendations for upgraded units or additional placements. Digital-display detector options for homes with chronic exposure concerns.

Equipment We Use for Testing

Testo 320 combustion analyzer:
Industry-standard combustion analysis. Measures O₂, CO (ppm and air-free ppm), CO₂, flue gas temperature, combustion efficiency. Calibrated annually per manufacturer specification.
Bacharach Monoxor III CO meter:
Electrochemical CO sensor with digital display, ppm resolution. Used for ambient CO measurement in occupied spaces. 10-second response time. Calibrated annually.
Industrial Scientific Ventis Pro 5 multi-gas:
Combination CO + combustible gas + oxygen + hydrogen sulfide detector. Used in commercial applications and where multiple gas concerns are present. Calibrated quarterly.
Bacharach H-25 gas leak detector:
Combustible gas detection for identifying gas leak sources contributing to combustion issues. Used as supplemental tool during CO investigations.
Manometers:
Multiple digital and analog manometers for measuring draft pressure, gas pressure, and combustion-related pressures during testing.

Pricing Reference (Q2 2026)

Annual CO testing included in fall furnace tune-up:
Included in $129 furnace tune-up or Comfort Care plan ($189/year). The combustion analysis and ambient CO measurement included in the 19-point checklist effectively functions as annual CO testing for homes with one gas appliance (the furnace).
Comprehensive CO testing (all gas appliances + ambient measurement):
$245-$485 per visit. Includes combustion analysis at each gas appliance, ambient measurement at multiple locations, equipment inspection, detector evaluation, written report.
Emergency CO investigation (suspected exposure):
$245-$385 for after-hours emergency dispatch. Includes initial assessment, equipment shutdown if hazardous conditions found, source identification, written report for medical and insurance purposes.
Post-renovation CO testing:
$245-$385. Verifies safe combustion and ventilation conditions after air sealing or renovation work that may have affected existing equipment.
Pre-purchase due diligence testing:
$345-$485. Comprehensive testing with detailed written report suitable for real estate transactions.
Detector upgrade and installation:
$85-$245 per detector installed (depending on type). Recommended detectors include Honeywell BW Solo (digital display, $95), Kidde Nighthawk RV (digital display with memory, $65), Industrial Scientific Ventis Pro 5 (commercial-grade, $385).
Comfort Care plan integration:
Annual CO testing included as part of fall furnace tune-up for plan members. Plan also provides priority dispatch on any suspected CO incidents.

What to Do If Your CO Detector Alarms

  1. Get everyone outside immediately. Including pets. Don’t try to identify the source from inside; the air may contain dangerous CO levels.
  2. Call 911 from outside. Salt Lake City Fire Department (or your municipal fire department) has hydrogen cyanide and CO detection equipment to verify safe conditions and identify sources.
  3. Do not re-enter the home until the fire department clears it. Even if the alarm stops, residual CO may remain.
  4. Seek medical attention if anyone has symptoms (headache, nausea, dizziness, confusion). CO poisoning treatment may include 100% oxygen administration; medical professionals can verify exposure with carboxyhemoglobin blood test.
  5. Schedule professional CO testing before resuming normal occupancy. Even after the immediate hazard is cleared, the underlying source must be identified and repaired.
  6. Don’t reset the detector without identifying the source. False alarms are rare; the alarm indicates real exposure occurred.

Common Concerns

How much CO is safe?
Ideally zero (outdoor background). Realistically: under 9 ppm sustained per EPA NAAQS. Under 25 ppm for short-duration exposure per WHO guideline. Above these levels indicates a problem to investigate even if no detector is alarming.
How long do CO symptoms last?
Mild exposure symptoms (headache, mild nausea) typically resolve within hours of removal from CO source. More severe exposure can cause lasting neurological effects including cognitive impairment, memory issues, and personality changes. Anyone with significant CO exposure should see a medical professional even if symptoms appear to resolve.
Can I test for CO myself?
Consumer-grade CO meters (Kidde Nighthawk RV with digital display, Forensics Detectors CO meter) can detect levels above 1 ppm with reasonable accuracy. These provide useful early warning but don’t replace professional combustion analysis at equipment. For chronic exposure investigation or after detector alarm, professional testing with calibrated equipment is recommended.
Do CO detectors expire?
Yes. Most UL 2034 detectors have 5-10 year operating life. The electrochemical sensor degrades over time even when the unit appears to function. Replace per manufacturer recommendation. Some newer units have a “replace by” date printed on the housing for verification.
What’s the difference between CO and CO2?
Carbon monoxide (CO) is a deadly poisonous gas produced by incomplete combustion. Carbon dioxide (CO₂) is a non-toxic gas produced by complete combustion and human respiration. CO is the safety concern in combustion equipment; CO₂ is monitored separately as a ventilation indicator (high CO₂ in a home indicates inadequate fresh air exchange but is not directly toxic at typical residential levels).

Frequently Asked Questions

Why isn’t my CO detector going off if you measured CO in my home?
UL 2034 CO detectors are designed to alarm at sustained 70+ ppm exposure. Lower concentrations (15-50 ppm chronic exposure) are below the detector alarm threshold but still cause health effects. Professional measurement with calibrated equipment detects exposure levels that residential detectors don’t catch. This is the most common reason for unexplained chronic symptoms in homes with gas equipment.
How often should I have professional CO testing done?
Annual testing during fall furnace tune-up is the standard recommendation for homes with one gas appliance (the furnace). Homes with multiple gas appliances (furnace, water heater, range, fireplace) benefit from comprehensive CO testing every 2-3 years in addition to annual furnace testing. Homes with older equipment (10+ years), attached garages, or sensitive occupants benefit from more frequent testing.
What’s the difference between a CO detector and a CO monitor?
CO detectors are designed to alarm at acute danger thresholds (70+ ppm). CO monitors are designed to display real-time CO levels (typically 1-99 ppm) for ongoing observation. Some products combine both functions (Honeywell BW Solo, Industrial Scientific Ventis Pro 5, Kidde Nighthawk RV). For chronic exposure monitoring, the dual-function units provide more useful information than basic alarm-only detectors.
Should I have CO testing done during the summer?
Useful but lower priority than fall testing. CO production is highest during peak heating season when combustion equipment runs continuously. Summer testing is good for verifying water heater and range conditions, but the most diagnostically valuable testing happens after equipment has been running through heating season demand.
Can pets detect CO?
Not reliably. Pets may show symptoms at higher exposure levels (vomiting, weakness, seizures) but this isn’t an early warning system. By the time pets exhibit clear CO poisoning symptoms, human occupants are at serious risk. Professional CO testing and properly-functioning detectors remain the standard protection.

Schedule CO Testing

Annual CO testing included with fall furnace tune-up. Comprehensive multi-appliance testing or emergency CO investigation available. Detector upgrades and proper placement consultations available.

Schedule Testing →

Office Hours

  • Emergency Service: 24 hours a day, 7 days a week
  • Office Staff: Monday – Friday, 8:00 AM – 5:00 PM
  • Closed: Weekends and State/Federal Holidays (emergency line always active)

Request a Estimate today

Contact Info

(385) 300-1867Phone
info@saltlakecityheatingairconditioning.xyzEmail