Smoke Alarm Goes Off When Heater Turns On [5 Easy Fixes]

The main reasons why the smoke alarm goes off when heater turns on are burning dust and debris, the smoke detector also works as a heat detector, a high amount of carbon monoxide in the air, a faulty smoke alarm, and an oil-coated heating element.

smoke alarm goes off when heater turns on

Keep reading this article to find out more about these common issues smoke alarm goes off when heater turns on and how you can fix each of these issues. Let’s dive in!

Table Of Contents

Smoke Alarm Goes Off When Heater Turns On [5 Easy Fixes]

If you’re wondering why the smoke alarm goes off when I turn on the heater, here are the typical reasons behind it:

Note: You can also read how to fix Mr Heater’s big Maxx problems.

1. Burning Dust And Debris

Turning on your heater after a few months can produce a burning smell. It’s not too big of a concern, but it can be annoying for people with asthma or other health problems related to breathing.

The main reason behind this smell is the accumulation of dirt and debris in the heater.

When the dirt burns, it leads to an unusual smell and also causes the smoke alarm to go off. It usually builds up in the air vents, registers, or the furnace when you keep the heater turned off for a long period.

If the smell is extremely bold and you get a musty odor, it could be due to the build-up of mold in the air ducts of your heater.

Be on the lookout for the smell of burning oil, plastic or electrical components as these are a potential fire hazard and lead to small fires in your house.

The burning smell normally goes away within a few hours after turning it on. By that time, the dirt gets burned and the smell fades because of it. But sometimes, the smell can stay for a few days.


A good trick you can do to avoid this burning smell in the first place is to clean the filter and the air vents of the heater before you turn it on after a long gap. Not only will it prevent the bad smell but also improve the quality of air.

But if you’ve already turned on the heater, the dirt has now gotten into the blower and it’ll take the help of a professional HVAC expert to clean it.

We advise you to wait for a few days as the smell should go away on its own when the dirt is burned off. But if that doesn’t happen, call in the expert to do a thorough cleaning of the heater and get rid of the burning smell.

2. Smoke Detector Also Works As A Heat Detector

If your smoke alarm goes off when a heater turns on, another common reason behind it is that the smoke detector also works as a heat detector. These types of smoke detectors are called combination smoke heaters.

They can go off both due to smoke or when the temperature in the room increases. When you turn on the heater, it raises the temperature in the room and it can cause these combination smoke heaters to go off.


This problem will go away on its own when the smoke detector gets adjusted to the new temperature. Don’t turn on your heater when the room temperature is too cold as it’ll put a lot of pressure on the heater and smoke detector.

3. High Amount Of Carbon Monoxide In Air

Another reason why the smoke detector went off when the heater is turned on is when there is too much carbon monoxide in your home. You’ll have a huge amount of carbon monoxide when you use both the AC and your heater at the same time without caution.


Carbon monoxide is a highly dangerous and toxic gas. Inhaling too much of it can cost you your life. You have to proceed carefully when you turned on the heater and the carbon monoxide alarm went off.

So, the first thing you should do is get out of the house and notify the emergency services. Once the issue is taken care of, reset the smoke detectors in your house again.

4. Faulty Smoke Alarm

When your smoke alarm goes off for no reason, it could be due to the fact that it has gone bad. Smoke detectors normally have a lifespan of 8-10 years. If that time has passed, your smoke detectors can go off randomly.


Replace the smoke alarms if it has been a long time since they had been installed. You can use ionization smoke alarms in your next installation as they do a great job of detecting short-flame fires.

5. Oil Coated Heating Element

The common reason why a new furnace sets off the smoke alarm is that the heating element has an oil coating.

When you turn it on for the very first time, the oil is burned off. That leads to a pungent smell which is detected by the smoke detector and causes them to go off.


Make sure the plugs are tight and the burners are working properly first to ensure that there was no mistake during the installation process.

If the installation is okay and there’s no leakage, the smoke detectors will automatically stop beeping after a while when the oil is burned.

How To Reset Smoke Alarm

The smoke alarm goes off because of one of these two reasons:

  • They detect smoke or heat.
  • They’re running low on battery.

If they’re detecting smoke, identify the source of the smell. One smoke alarm going off can trigger all the smoke alarms.

Once you make sure that there’s no fire and you identify the smoke detector that’s going off, you can press the button you see on it for three seconds and it’ll be reset.

If the smoke alarm randomly beeps, it’s most likely caused by a battery issue. When all the smoke alarms go off, that indicates fire and when just one alarm goes off, that is usually caused by a low battery.

Follow these steps to change the battery on a smoke detector:

  • Identify the smoke detector that has a low battery.
  • Use a ladder or a chair to access the smoke detector.
  • Locate the battery panel in the smoke detector that is located either at its side or back.
  • Find the battery once you’ve accessed the battery panel.
  • Remember where the positive and negative charges are positioned.
  • Take the old battery out and install the new one in its place.
  • Close the battery access panel.

How To Prevent A Fire Hazard From Heater

The proper maintenance of your heater makes sure that it’ll function well in the long run and avoid the burning smell that sets off the smoke alarm.

Follow these maintenance tips to take good care of your heater and make sure you don’t burn anything in your house:

  • Don’t store any combustible materials close to your heater.
  • Replace the air filter at regular intervals.
  • Test the carbon monoxide and smoke alarms before turning on the heater after a long period.


Can a burning smell set off a fire alarm?

Yes, a burning smell that comes when the dust is burned can set off a fire alarm. The bad odor usually comes from sulfur dioxide and it can easily trigger the fire alarm.

Why smoke alarm randomly goes off?

The main reasons behind the smoke detectors going off randomly are when they are running on low battery or they have worn out due to prolonged use.

What temperature will set off a smoke detector?

Most of the smoke detectors that detect heat or combination smoke alarms go off when the temperature crosses 100 degrees Fahrenheit. When the temperature goes below 40 degrees, the battery of the smoke detector can be damaged.

Why do smoke alarms go off for no reason?

Smoke alarms often go off without any reason when the battery has not been changed in a while. It’s also the most common reason behind false alarms from smoke detectors.


It can be extremely frustrating when the smoke alarm goes off when heater turns on and you don’t know why it’s happening. But now you know the main reasons why it happens and how you can fix it.

We hope this guide has helped you identify the exact reason why your smoke alarm is going off and how to address it so that you can stay warm and cozy in your room.

Leave a comment below if you have any more questions about why heaters trigger smoke detectors.

About David

David is a man who loves doing research and finding out the best solution to any type of heating appliance issues like heaters and fireplaces. Whenever he finds the perfect solutions to any issues of heating appliances after doing in-depth research, he loves to share them with his readers. In fact, his aim is to help his readers to fix the issues with their heating appliances easily.More about us .

Leave a Comment