What to Do When Your Furnace Stops Working in Winter
Stay Calm and Check the Basics First
Waking up to a freezing house is every homeowner’s nightmare. Before you panic, there are several simple checks you can perform that might restore your heat without a service call.
First, verify that your thermostat is set to 'Heat' and the temperature is higher than the current room reading. Sometimes, a simple battery replacement or accidental setting change is the culprit.
If you find that your controls are unresponsive, you may need to learn how to replace a thermostat to restore communication with your furnace. Next, check your circuit breaker panel to ensure the furnace switch hasn't tripped to the 'Off' position.
Check Your Air Filter and Vents
A dirty air filter is one of the most common causes of furnace failure. When airflow is restricted, the heat exchanger can overheat, causing the system to shut down for safety.
- Replace your filter if it appears grey or clogged with dust.
- Ensure all supply registers and return air grilles are open and unobstructed.
- Verify that your outdoor exhaust pipes are clear of snow and ice buildup.
If you have a zoned system, you might also want to understand how to adjust duct dampers to ensure heat is reaching the most critical areas of your home during an outage.
Is the Gas or Power Supply On?
For gas furnaces, ensure the gas valve is in the 'On' position. If you smell a faint odor of rotten eggs, stop immediately and leave the house.
Safety should always be your priority. Knowing how to check for gas leaks safely can save lives, but when in doubt, call your utility company or the fire department from outside the home.
If your furnace is a high-efficiency model, check the condensate drain line. If this line becomes clogged or frozen, a safety switch will prevent the furnace from firing up to avoid water damage.
Staying Warm While Waiting for Repair
If troubleshooting doesn't solve the problem, you need to protect your home and family until a professional arrives. Dress in layers and gather everyone in a single room to preserve body heat.
While waiting, you might consider using electric heaters. It is helpful to understand the difference between a portable heater vs space heater to determine which is safest for your specific room layout.
Keep in mind that running multiple electric heaters can be expensive. Many homeowners are surprised by the cost of temporary heating when their primary system is down for several days.
Prevent Secondary Damage to Your Home
One of the biggest risks during a prolonged heating failure is the potential for burst pipes. When the indoor temperature drops below freezing, water inside your plumbing can expand and crack the pipes.
Take proactive measures and learn how to prevent frozen pipes by dripping your faucets and opening cabinet doors to let warmer air circulate around the plumbing.
When to Call a Professional
If you have checked the power, gas, and filters but the heat still won't come on, it is time to call in an expert. Complex issues like a cracked heat exchanger, a faulty inducer motor, or complex wiring issues require professional diagnostics.
For those with advanced systems, a technician might need to look at specialized components, such as explaining how to wire a two-stage thermostat if the control signals are the root of the problem.
You can find trusted, pre-screened HVAC contractors on HVACDatabase.com to get your system back up and running quickly. Our directory connects you with local experts who specialize in emergency furnace repairs and maintenance.
Summary Checklist
- Check thermostat settings and batteries.
- Verify the circuit breaker is on.
- Inspect and replace the air filter.
- Ensure outdoor vents are clear of snow.
- Check for gas or power supply issues.
- Call a pro via HVACDatabase.com if the unit stays off.
Don't wait until the middle of a blizzard to find a repair person. Keeping a reliable HVAC professional in your contacts ensures that when the heat goes out, you aren't left in the cold for long.