https://utilityexplained.com/tags/carbon-monoxide/Recent content in Carbon Monoxide on Utility ExplainedHugoen-usSat, 27 Dec 2025 00:00:00 +0000https://utilityexplained.com/blog/why-is-my-furnace-blowing-cold-air/Sat, 27 Dec 2025 00:00:00 +0000https://utilityexplained.com/blog/why-is-my-furnace-blowing-cold-air/<h2 id="quick-answer">Quick Answer</h2> <p><strong>Treat unexpected cool air from a heating system as a safety question first, not a DIY repair challenge.</strong> Work through this check order before you call anyone:</p> <ol> <li><strong>Thermostat mode</strong> — is it set to HEAT and the set point above the room temperature?</li> <li><strong>Fan setting</strong> — is the fan on AUTO, not ON?</li> <li><strong>Air filter</strong> — is it clean, or is it clogged and blocking airflow?</li> <li><strong>Breaker and service switch</strong> — is the furnace getting power?</li> <li><strong>Exterior intake and exhaust</strong> — are they clear of snow, ice, or debris?</li> <li><strong>Carbon-monoxide alarm</strong> — does the test button work?</li> </ol> <p>If your carbon-monoxide alarm sounds, you smell fuel or smoke, or anyone has symptoms such as headache, dizziness, weakness, nausea, or confusion, stop here and get help immediately.[1]</p>