Why Smoke Alarm Goes Off When Heater Turns On [Reasons & Solutions]

The winter season is knocking at your door, and the evening starts getting a bit chilly. That’s why you turn on your heater to convert your cold room into a cozy space. But the heck is- smoke alarm goes off when heater turns on. 

First, you think it’s normal as you run the heater for the first time this winter. Later, you get a bit confused and ask yourself- what if it causes a fire hazard? To clear your inner confusion, we are here to help you out.

Most probably, your smoke alarm goes off when you turn on your heater because of the cobwebs, dust, spiders, and other insects inside of your heater, the increase of carbon monoxide inside your room or home, defective detector & if your smoke detector works as heat detector.

why smoke alarm goes off when heater turns on

However, in this guide, we will break down why smoke detectors chirp when heat comes on and how you can fix the issue. So, stay calm and continue to read. 

Why Smoke Alarm Goes Off When Heater Turns On [Reasons & Solutions]

The smoke alarm may go off for multiple reasons. For example, the smoke detector may get tripped due to the wrong installation.

why smoke alarm is going off when I turn on my heater

Below, we have included the most common reasons that are responsible for getting the smoke alarm turned off. 

1. Dust Build-Up On The Heating Element

When you don’t use the heater during the entire summer season, it collects dust, cobwebs, spiders, and other insects. In return, dust build-up is formed on the heating element.

When you crank it up for the first time in the winter season, all that dust burns up and blows through the system. 

Due to this burning up, it creates smoke or a fire smell. In some cases, the smoke smell gets strong, which is responsible for activating the smoke detector. Here dust is the culprit.  


Clean: Dust build-up on the heating element is the main culprit behind a faulty smoke alarm. So, cleaning the heating element before running your heater for the first time will be the best solution. 

So, take your vacuum and start vacuuming on and around the unit to get rid of dust, spiders, and cobwebs. Also, you can hire a professional to clean your furnace professionally. 

Reset the Smoke Alarms: It’s normal when you turn the heater on for the first time in a season. Once the burns are done, it automatically fixes the issue. However, you can reset the smoke alarms if a strong smell activates the smoke detector. 

reset your smoke alarm

We recommend you call a technician or a monitoring company and let them test your heater. It will help to overcome any issue- even the potential fire hazards. 

2. If The Smoke Detector is Also a Heat Detector

Hard-wired or combo smoke heaters may be responsible for shutting the smoke alarm off. Here combo means the smoke detector in your home also functions as a heat detector.

When you turn your heater on, the smoke alarm goes off. Turns out, the smoke detector will also go off if your room temperature changes drastically. 


Once your room temperature adjusts enough, the problem will be solved automatically. Also, avoid turning your heater on when the temperature becomes too cold.

It puts pressure on your heater as well as on the smoke detector. To prevent any damage, call a professional electrician for help and let him fix the issue for you.  

3. Check If It’s Carbon Monoxide Alarm

The smoke alarm doesn’t only go off for a defective smoke detector. Sometimes a high level of carbon monoxide (also known as CO detector) in your room or home causes the smoke alarm to turn off.

If you run a heater and the AC at the same time, carbon monoxide may start pumping through your home if you are not careful. 


First off, leave your home immediately if the CO detector detects the presence of carbon monoxide in your house. Then, call 911 for help. Afterward, don’t forget to replace the smoke detector with a new one. 

4. How Old Your Smoke Detector

Generally, the lifespan of a smoke detector is 8-10 years. Then, you must replace the smoke detector. Otherwise, the smoke alarm will turn off without any reason when you turn on your heater. 


When the date of your smoke detector will expire, just replace it with a new one. 

Safety Tips

According to NFPA, 3 out of 5 house fire deaths occur without a smoke alarm or with a non-functional one. NFPA observes the death number gets double in a home that has no smoke alarm. 

Indeed, a smoke alarm is a life-saving device that protects you from potential fire hazards by alarming you. But if you fail to maintain the below safety tips, a smoke alarm will be worthless. So, ensure you properly maintain the following safety tips. 

  • Make sure you keep your smoke alarm away from drafts made by air ducts or fans. Otherwise, the air from the fan can blow the sensor away on your smoke detector.
  • Never set your smoke alarm near your bathroom shower or kitchen stove. If you want to install it near your kitchen, you must set the smoke alarm at least ten feet far from the cooking appliances.  
  • Choose the right type of smoke detector.
  • Install the smoke alarm by following the rules and regulations implied by the local administration. If you don’t know, learn about smoke alarm safety laws

Maintenance Tips

Check out the following maintenance tips to let your smoke alarm function for years to come. 

  • Inspect the unit every month.
  • Change the batteries timely or at least once a year.
  • Use a vacuum cleaner with a brush attachment to tidy up the unit on and around. 
  • Replace the smoke heater with a new one every 10 years. 


Can a smoke detector go off because of heat?

Yes, a smoke detector can go off if it senses a temperature change. When the heat level reaches its highest level, the smoke alarm goes off. 

Why does my electric smoke detector go off for no reason?

If the battery comes to an end or you don’t change them often, your electric smoke detector will turn off for no reason.

What temperature will set off a smoke detector?

When the temperature reaches 32-100 degrees Fahrenheit, it will set your smoke detector off. 

Why do smoke detectors go off at night?

If the battery life comes to an end, it generates the amount of power responsible for internal resistance. Therefore, it increases the resistance due to the low temperature at 2-6 am. All of these are responsible for the sudden shut-off of your smoke detector at night.

How do you know if your smoke alarm detects carbon monoxide?

If the smoke alarm makes 4 beeps and a pause, understand there is carbon monoxide in the air. 


From above, now you know why the smoke alarm goes off when the heater turns on. Whenever you face such a problem, our first suggestion is to turn off the heater first and fix the issue following our guide.

The next suggestion that we can give you is- to hire an expert HVAC guy before turning on your furnace for the first time in the winter. 

If there is an issue, the HVAC guy or maintenance company will fix that and protect you & your house from potential fire hazards. 

About William

William is the founder of Fireplacehubs.com. He has real life practical skills in fixing smoker & heating appliance issues. He loves to share his knowledge & helps others in fixing their appliances & saving their money. William firmly believes that anyone can repair his or her unit with the correct guidance & knowledge. See more at about us.

2 thoughts on “Why Smoke Alarm Goes Off When Heater Turns On [Reasons & Solutions]”

    • Hi Mary

      When you run your unit after a long period, maybe the smoke smell is so strong due to dirty heating elements. Consequently, the smoke alarm goes off.

      In such a case, cleaning the heating element before running your unit for the first time will be the best solution. Also, you can hire a professional to clean your furnace professionally.

      Plus, if such a situation happens, reset your smoke alarm to avoid any real danger.

      Best of luck!


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