Apartment Heater Not Working? 13 Problems And Solutions

When your apartment heater stops working, it can be cause for concern, or it can be something as simple as overheating or a dirty air filter.

While many problems with your apartment heater will require an HVAC technician to repair the problem, we find that sometimes apartment owners can fix these simple issues with a little troubleshooting.

We have included troubleshooting tips in this article to help you address most of the common problems you may encounter with your apartment heater.

13 Reasons your Apartment Heater is Not Working

1. Furnace Overheating

One common reason why heaters may not work is that the furnace overheats. The heater can overheat when there are too many demands for heating. In this case, it needs to be checked and serviced by a professional technician.


The solution to this problem is to check the airflow and clean out any debris blocking it. If you are using an air filter, make sure that it is cleaned or replaced every month so your heaters do not work harder than they should.

2. Too Much Gas

Furnaces are designed to burn a specific quantity of gas. Manufacturers provide specifications regarding the amount of gas their equipment can and should burn.

In other words, you have to calibrate the equipment during installation to ensure that it functions properly.


Adjust the equipment until it burns only the required amount of gas. The best time to do this is during installation.

3. Dirty Air Filter

When the air filter is dirty, it restricts airflow and causes your heater to work harder. As a result, you can hear vibration noises from the fan belt. In addition, clogged or dusty filters can damage the electrical components that control the flow of warm, humid air into your home’s air vents.

This may lead the heater to overheat and shut down, which is not what you want at all!


The easiest way to solve this problem is by replacing the dirty air filter. Replacing your heater’s air filter is usually an inexpensive fix. Make sure the cover on your furnace air filter is correctly installed if you replace it. The furnace may not turn on if the door to the unit isn’t closed.

It’s recommended to change your air filter if it has lasted you over 3 months. This is because disposable air filters should be replaced every 1-3 months and not longer.

4. Thermostat Not Set to “Heat”

A thermostat is a device that controls the temperature of a room. A simple model for this would be an oven where you set the desired temp, and when it reaches your selected number, it turns off until needed again. In apartment heaters, there are two main types of controllers: PID or PWM.

A PID controller works by cycling on or off based on its programmed settings. The PWM controller modulates the power to maintain constant output temperatures in response to varying demand from heating loads.

However, both goals are similar: to regulate the heater so that it doesn’t overheat itself or burn out beyond its rating limits. If your thermostat isn’t set at “heat,” then it will just keep the heater on at a low setting.


Ensure that your thermostat is set to “heat” if you are expecting heat from your apartment. If not, adjust accordingly before calling maintenance or service personnel for help.

5. Low Refrigerant Levels

If the heater is getting hot but not enough to heat your home, check out the unit’s refrigerant levels. The more you use it throughout the day, the lower these levels become and will need replacement soon.

If they are too low, there might be a leak in them that makes this happen. Your heat strips might turn on more frequently than you desire if this happens.

If your heat strips are coming on more frequently, it’s probably time to raise your refrigerant charge. The compressor may overheat and even fail if the level is too low for an extended period of time.


Fix the leak and raise your refrigerant charge if needed. Additionally, keep an eye on the compressor and make sure it doesn’t overheat.

6. Flame Sensor Isn’t Working As it Should

A flame sensor is a device that allows for efficient and safe heating. It automatically detects whether the pilot light is burning or not. If it isn’t, then this means that there may be some issues with your heater system.

In some cases, the flame sensor may not be working as it should. In this case, you could have a blocked pilot light orifice that keeps your heater from lighting properly.


You will need to remove any soot and carbon buildup to ensure proper airflow for easy ignition of the gas furnace pilot light.

7. Dead Blower Capacitor

An apartment heater may not work because of a dead capacitor. A capacitor is an electrical component that produces power to the motor in the blower assembly. When this part becomes faulty, it means that your heater will not function at all.

The repair process involves replacing the defective capacitor with one that can produce enough voltage needed by your unit’s fan and other components.

If you are still having trouble, though, then there might be something wrong with another individual piece within the whole system. Besides that, you may have a more serious problem on your hands, such as broken wire insulation or circuit board damaged beyond use.


Replace the capacitor with a new one. Usually, this is a more inexpensive approach than leaving it in and allowing the dead blower capacitor to cause even more damage.

8. Bad Inducer Draft Motor 

The apartment heater may not work if the inducer draft motor is bad. The problem with this part of the heating system is that it does not allow any air to pass through. As a result, no heat will exit from the furnace.

If there was some blockage in the front of an opening or near where hot gases are exiting, you could also have trouble getting your unit started up properly. Over time, the inducer draft motor can acquire dust and debris, resulting in the safety switches shutting off the furnace.


If the inducer draft motor is bad, then it will need to be replaced. The good news about this part of the heating system being faulty is that other parts are fine.

Therefore, your heating system should work properly once you have replaced this small but important component.

9. Cracked Heat Exchanger

If a heat exchanger is cracked, it’s not always going to result in a broken furnace. Still, we feel compelled to bring this up since:

  • It might harm the functioning of your system, and it will become evident when it gets severe.
  • Heat exchangers that have cracked are sometimes a sign of a more serious issue, such as a blockage in the ventilation system.


It’s not always easy to find the crack on a heat exchanger, so you should get in touch with technicians who can help you locate and fix this issue.

The issue with heat exchangers is that they contain carbon monoxide (CO). Hence, carbon monoxide leaks out when they break, which is highly poisonous and can be deadly in severe situations.

In conclusion, you should replace a cracked heat exchanger, and if your furnace is past its prime, you should certainly replace it as well.

10. Faulty Ductwork or Installation Design

The first thing to check for this reason would be whether there are any holes in the metal piping which feeds into each room’s heating units.

All lines should have a programmable thermostat attached throughout the house to be turned on and off as needed. If the heat is only working sporadically, it could be that you don’t have one of these thermostats in place.


Fix any holes in the metal piping or install a programmable thermostat. Also, ensure that all rooms have heating units as needed.

11. Furnace Leaking or Producing an Odor

A furnace that is leaking or producing a bad smell can be due to several issues. First, it could indicate an issue with the blower fan and motor assembly in the case of a gas furnace.

Second, you should check the burner compartment in case if it’s a forced-air heater for any leaks from components such as valves, gaskets, and heat exchangers.

Third, you should check the gas lines for any leaks or obstructions causing issues with ignition. If there is a broken seal on an oil-fired furnace, it can also produce a bad smell.


Your HVAC technician will need to inspect the furnaces and then use the necessary parts to fix these problems for all of these problems.

12. Lack of Maintenance

Without regular maintenance, heaters can develop cracks in their casings and may leak dangerous gases into your home. They also need to be cleaned regularly to work efficiently.


If you are renting or leasing a property with heating services included, make sure that professionals maintain it regularly.

13. Furnace Too Big for Your Apartment

A furnace that’s too big for your space will have issues with the airflow and gas usage, which creates a situation where the heater won’t work properly.


The solution is to get an appropriately sized unit or get one fitted into place by a professional. If you are having problems with the furnace, you may need to get it replaced.

Wrapping Up

Finding why your apartment heater is not working and fixing the problems will save you a lot of money. If you can fix it yourself, then that’s even better! You’ll learn something new while saving money.

However, don’t risk your health or more damages if you feel the problem with your apartment heater is too complex to handle. This is why there are professionals who can fix or replace your apartment heater for you.