Is it bad for furnace to run constantly in extreme cold weather?

Author: Bridgette Halvorson III  |  Last update: Wednesday, February 19, 2025

Winter weather puts your furnace to the test. After months of being dormant, the system suddenly finds itself working overtime. While it should cycle throughout the day, clicking on too frequently may indicate a problem.

Is it okay for my furnace to run constantly in cold weather?

Ideally. Your furnace will run constantly during the coldest day of its operating life. 6 hours run time is fine as long as it's not constantly turning on and off, you should see at a 5-10 minute run time. 22 C is definetly higher than it needs to be, but if that's the comfortable temp for you that's fine.

Can it be too cold for a furnace to work?

Systems aren't designed with this temperature in mind. The heating load is typically designed around 0 degrees. Any colder and your system will struggle to keep up. As long as the pipes are still hot, it's still functioning.

What happens if a furnace runs constantly?

Your blower is probably the cause of a constantly running furnace if the system is turned on but doesn't produce any warm air. Corroded wires or a blown fuse can cause this issue. Since this problem involves electrical components, contact a technician to fix the problem safely.

Can extreme cold cause furnace problems?

Yes, weather can affect a gas furnace. Extremely cold temperatures can strain the furnace and potentially lead to issues like reduced efficiency or even breakdowns. Regular maintenance, proper insulation, and ensuring proper ventilation can help mitigate weather-related impacts on a gas furnace.

Heat Pump Runs All The Time

Can extreme cold cause furnace to short cycle?

When temperatures outside are extremely cold, it is normal for some extra cycles to occur. When a furnace is short cycling, it's working hard to produce heat but isn't making any, causing strain on your furnace.

What should I set my furnace to in extreme cold?

During the frigid cold temperatures, set your thermostat on a permanent HOLD around 70 degrees until the weather warms back up to normal temperatures for this season. When temperatures drop below zero or even below freezing for extended periods of time, sometimes your furnace can't keep up.

Will a furnace shut off if it runs too long?

If the furnace runs too long, it will overheat and shut off before your home reaches your desired temperature. Repairing your home's ductwork will improve heat distribution and your furnace's heating ability while preventing short cycling.

What do you do when your furnace won't stop running?

On your thermostat, look for the fan settings. There should be two, “ON” and “AUTO.” If it seems like your furnace won't turn off, the thermostat may be set to “ON” for the blower. Toggle the switch to “AUTO” so your furnace's blower fan only runs during a heat cycle.

Can a gas furnace freeze up in winter?

On extremely cold days, homes with gas furnaces are at risk of a specific problem – freezing.

Why does my furnace keep shutting off in extreme cold weather?

Dirty filters are the most common culprits of this problem. Poor ductwork installation is another one. Blocked air returns, closed vents, or dirty furnaces all can cause similar problems. You might also have an evaporator coil with a layer of lint covering it.

Is it OK to leave furnace on all the time?

During the coldest days in winter, it is normal for a furnace to run almost constantly to keep the home warm. As long as the furnace is running efficiently and not making strange noises, the constant operation is likely nothing to worry about. But in general, your furnace should not constantly be running.

What temperature to keep a house in extreme cold?

The World Health Organization (WHO) recommends setting your thermostat no lower than 64 degrees (F) in the Winter months while people are in the home. If there are infants or elderly individuals, they recommend keeping the temperature at 70 degrees at a minimum.

How cold is too cold for a furnace?

Before you get worried that your furnace is broken, be mindful that your home heating system is actually only designed and sized to operate at a low outdoor temperature of 0 degrees Fahrenheit.

How long can a furnace fan run continuously?

A common misconception about furnaces is that running your HVAC fan nonstop will cause it to give out early. However, this isn't the case, especially with newer units designed to run 24/7. Consistent fan operation should not be an issue if your HVAC system was installed by experienced professionals.

How to keep your furnace from freezing?

How Can You Prevent Your HVAC Unit from Freezing Up in Winter?
  1. Change your air filter regularly. To keep your system efficient, change out the air filter at least once a month. ...
  2. Clean the fan. ...
  3. Keep your vents open. ...
  4. Keep the condenser coils clean. ...
  5. Schedule a professional inspection.

Why does my furnace run constantly in cold weather?

A poorly insulated home with drafts and air leaks can prevent your home from reaching the desired room temperature causing your furnace to run continually. It can also lead to rooms cooling down too quickly causing the furnace to turn on shortly after turning off making it appear as if it is constantly running.

Why is my furnace not shutting off at temp?

The short answer is your furnace won't turn off due to some kind of error or malfunction within your furnace, thermostat, or HVAC system. It could be the wrong thermostat setting is being used, a clogged air filter or your thermostat itself is no longer working properly.

What happens if your furnace keeps running?

If you do find that your furnace is seemingly always running, it often indicates that there's an issue that's limiting how much heat it produces. This may be something you can easily fix on your own, but it will usually require having a furnace technician inspect your heating system to pinpoint the specific cause.

Is it bad for a furnace to run nonstop?

Running your furnace constantly can put extra strain on the system, potentially shortening its lifespan. It is important to have your furnace regularly maintained to ensure it is in good working condition and not being damaged by constant use.

How long should a furnace run in cold weather?

Furnace Heating Cycles Average 10 to 20 Minutes

Once the heat is flowing, it will continue to run until the thermostat detects the set temperature. For your typical residential furnace, that cycle lasts around 10-15 minutes. Sometimes a cycle can last up to 20 minutes, usually in particularly cold weather.

Is it normal for a furnace to turn on every 10 minutes?

Most furnaces kick on and off between three to eight times an hour, depending on things like outdoor air temperatures, the furnace's age, and how much insulation you have. That's why, instead of asking how often a furnace should cycle, it's best to stay alert to changes in how your furnace is running.

Can extreme cold cause a furnace not to work?

Your furnace can only maintain a differential between outdoor and indoor temperatures to a certain degree. During extremely cold weather, some furnaces might not be able to bring a home up to its desired temperature level.

Is 72 too high for a thermostat in winter?

68 to 72 degrees is a temperature range that is not too warm or cool, and is sufficient enough to warm up the home just enough so that everyone is comfortable regardless of the type of clothing they have on.

Does outside temperature affect the furnace?

Yes, the outside temperature significantly affects your HVAC system's performance. Both heating and cooling systems need to work harder in extreme temperatures, leading to increased energy consumption and potential strain on the system.

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