Furnace not heating and the house getting colder by the hour? Before you call an HVAC company in Charlotte — even before you call us — run through these six checks. About half the no-heat calls we take end up being one of these, and most take under five minutes with no tools.
Safety first: if you smell gas, stop here. Do not flip switches, do not relight anything. Leave the house and call the gas company, then call us.
1. Check the thermostat mode and setpoint
Obvious, and still the number one finding. Make sure the thermostat is set to Heat, not Cool or Off, and that the setpoint is at least 3 degrees above the room temperature. If the screen is blank, replace the batteries — a dead thermostat reads exactly like a dead furnace.
2. Check the breaker
Find your electrical panel and look for the breaker labeled furnace or air handler. A tripped breaker sits in the middle position — flip it fully off, then back on. If it trips again right away, stop: something is shorting, and resetting it repeatedly is how motors burn out. That one is a service call.
3. Check the furnace switch
Near the furnace there is a switch that looks exactly like a light switch. It gets bumped off by laundry baskets, kids and holiday storage more often than you would believe. Make sure it is on.
4. Check the filter
A clogged filter chokes airflow, the furnace overheats, and a safety switch shuts the burners down — so you get a blower running with cold air, or short bursts of heat that quit. Pull the filter and hold it up to a light. If you cannot see light through it, replace it. If you are not sure which filter to buy, our guide to filter ratings and sizes covers it.
5. Check the condensate drain (high-efficiency furnaces)
If your furnace has white PVC pipes, it produces water when it runs. A clogged drain line trips a float switch that locks the furnace out. Look for a small tray or pump near the base — if it is full of water, that is your culprit, and clearing the line usually brings the heat back.
6. Check the vents outside
Those same PVC pipes exit through an outside wall. Leaves, snow, ice or a bird nest blocking them will shut the furnace down on a pressure fault. Clear the openings and let the furnace retry.
Still no heat? What happens next
If you got through all six and the furnace still will not fire, the likely suspects are an ignitor, a flame sensor, a capacitor or a control board — parts a technician can test in minutes but that are not safe do-it-yourself territory on a gas appliance. One more clue worth noting before you call: any unusual sound. A click-click-click with no ignition or a hard bang at start-up each point somewhere specific — our guide to furnace and AC noises explains what each one means.
We run no-heat calls across Charlotte, NC all winter, residential and commercial, same-day when the schedule allows. Call (704) 771 9671 and tell us what you found in the checks above — it helps us show up with the right part on the truck.
