A heater blowing cold or unheated air is usually caused by incorrect thermostat settings, a clogged air filter, tripped safety limits, or an ignition failure. Most issues can be resolved with simple resets and basic maintenance before needing a repair technician.
Check These 3 Easy Fixes First
Issues with the pilot light, high limit switch, blocked burners, leaky ductwork, electrical problems, and blower motor failures are common reasons for HVAC systems blowing cold air. These problems often require professional maintenance and repairs.
A: If your furnace is running but the house is not warming up, the problem is often related to airflow, thermostat settings, dirty filters, duct issues, or a heating component not operating correctly.
To reset your heater, locate the system's power switch (usually a light switch near the furnace or inside the front panel). Turn it off, wait 3 to 5 minutes, and turn it back on. Alternatively, flip the dedicated heater/HVAC breaker at your home's main electrical panel off, wait a full two minutes, and turn it back on.
All furnaces are equipped with a reset button. They are generally red or yellow and are located inside the blower compartment. The reset button is a safety feature that will shut down the furnace when a problem is detected, often a hot or overheating furnace, before it trips the circuit breaker.
Resetting can recalibrate the temperature sensor. Failure to Turn On HVAC System: A thermostat reset reboots its system and attempts to restart normal functioning. This resolves problems where it fails to turn on your AC, heat, or fan.
10 Things to Check if Your Heating System Isn't Working
How Long Can My House Stay Warm Without Heat? Most homes begin losing heat within a few hours, and depending on outside temperatures, can drop to unsafe levels within 12 to 24 hours.
To reset your furnace safely, lower the thermostat and turn off the power at the furnace switch or circuit breaker. Wait 2 to 5 minutes, then turn the power back on. If your furnace has an internal reset button (usually red or yellow), press and hold it for 30 seconds.
A heater blowing cold air is a common issue, usually caused by restricted airflow, a flame sensor problem, or thermostat malfunctions. The most effective first step is to check that your thermostat is set to "Heat" and the fan switch is set to "Auto" (rather than "ON").
One common indication is when the HVAC system fails to turn on altogether, suggesting a lack of electrical power. Another sign of a blown fuse is the inability of specific system components, such as the blower fan or condenser, to operate even when they have secure power connections.
To reset a furnace blower motor, turn off power to the furnace using the emergency switch or the circuit breaker. Wait 2-3 minutes, then locate the red or yellow reset button typically found on the blower motor housing. Press it firmly, and restore power.
The Most Common Home Heating Problems
Average blower motor replacement cost
Blower motor replacement costs $500 to $2,300, depending on the motor type, size, and speed, how easy the HVAC system is to access, the warranty status, and local labor rates. Replacing an ECM blower motor costs more than a PSC motor due to the higher part cost.
To quickly restart a heater or furnace, turn off the system's power switch or main breaker. Wait 3 to 5 minutes for the safety systems to clear, then turn it back on. If your unit stopped working due to a safety lockout, you may also need to press a red or yellow reset button.
No, 72°F is generally considered the ideal, standard room temperature for most homes. However, how it feels depends on the season and personal preference:
On average, pipes can freeze within six to eight hours when temperatures stay at 20 degrees or lower. If pipes are poorly insulated or exposed to drafts, they may freeze even faster.
5 Warning Signs It's Time for Furnace Replacement
To reset your heater, locate the system's power switch (usually a light switch near the furnace or inside the front panel). Turn it off, wait 3 to 5 minutes, and turn it back on. Alternatively, flip the dedicated heater/HVAC breaker at your home's main electrical panel off, wait a full two minutes, and turn it back on.
The heat exchanger is often considered the most costly part of a furnace to repair or replace. It is a critical component that transfers heat from the combustion process to the air that circulates throughout your home. Over time, heat exchangers can crack due to the constant heating and cooling cycles they undergo.
Most residential heaters last 10 to 20 years, depending on the type of system, local climate, and maintenance. Proper annual tune-ups can significantly maximize your equipment's longevity.
How can you tell if a thermostat is bad?
The reset button's location depends on your thermostat type. For older models, it is usually a recessed button on the circuit board (often behind the faceplate) or a dedicated button on the front or side. For modern smart thermostats, you typically reset the device through the digital menu.
Typically, a furnace should cycle 3 to 8 times per hour, running for about 10 to 15 minutes each time. If it's cycling more frequently (short cycling) or running for 20+ minutes straight regularly, something's not right.