Is your heat broken? 11 signs your furnace is dying.

old furnace

My heating once went out during below freezing weather and I didn’t know what to do. The boiler was running and I had hot water and heat, but there were cold spots in the house. I went to the local hardware store to get a new heating valve and circulator pump thinking that was the issue, but I failed miserably. 

I called a very pricey professional, and it turns out the furnace problem was just a lousy aquastat. An aquastat is just a device that kicks the boiler on and off when the thermostat calls for heat and to maintain the proper temperature.

In this blog post, you’ll read about the common signs of broken or dying heating systems and the steps you can take to fix the problem in your home.


If you’re having problems with your furnace, always start troubleshooting the thermostat. If you increase your thermostat and the boiler or furnace doesn’t kick on, there are a few other common signs that will hint your furnace is dying. Keep reading to learn more.

Common warning signs that your furnace system is broken or dying:

1. Your furnace is making strange noises

If you’re hearing weird noises from your furnace, it could be a sign that there’s a problem. The furnace might be trying to tell you that it needs attention; if you ignore the problem, it could worsen. Some common noises your furnace might make are:

Rattling or banging noises: This could be a sign that something is loose inside the furnace, and it needs to be fixed before it causes further damage.

Popping noises: This could be a sign of an overheating blower motor, and it should be checked out as soon as possible.

Humming noises: If your furnace is humming, it could mean that the motor is running low on oil or has a dirty air filter.

2. Other signs your furnace is dying is if it takes a longer time to produce heat.

If your heating system is not producing enough heat, it could mean that the furnace is dirty or there is a problem with the thermostat. You should also check to see if the furnace filter needs to be replaced. If your furnace isn’t producing any heat, that’s a sign that something is wrong and you should call a professional.

3. Your furnace is leaking water, or carbon monoxide detector keeps going off

heating system water leak

A furnace failure is the last thing you want to worry about during cold weather. If your furnace is leaking water, it’s essential to get it fixed as soon as possible. But if your furnace breaks down, it can damage your health.

One of the biggest dangers of a broken furnace is carbon monoxide poisoning. Carbon monoxide is a colorless, odorless gas that can cause serious health problems and even death. If your furnace is not working properly, carbon monoxide can build up in your home and cause poisoning.

Another danger of a broken furnace is mold growth. If your furnace is leaking water, it can lead to mold growth in your home. Mold can cause various health problems, including asthma attacks, respiratory problems, and skin irritation.

If the drainage system of the furnace becomes clogged, the water will back up into the furnace and cause it to leak. A clogged drainage system can also be a sign of a bigger problem, such as a cracked heat exchanger.

4. Your furnace is too old

Oftentimes, furnaces break down because they’re just old. They’ve been running constantly for years and eventually, they just give out. The average lifespan of a furnace is around 15-20 years, so if your furnace is older than that, it’s probably time to start thinking about a new heating system.

Another reason you could be facing furnace problems is due to old age and the parts are wearing out. The motors, heating elements, and other internal components can only run for so long before they need to be replaced. If you have an old furnace, it’s essential to keep track of the age of the different parts and replace them when necessary.

5. You’re constantly adjusting the thermostat

Suppose you’re constantly having to adjust your thermostat to get the desired results. In that case, it could mean a problem with your heating system or a faulty thermostat. Signs that can point to a defective thermostat include:

The thermostat is not accurately reading the temperature in your home, it could mean that the thermostat is faulty.

If your furnace turns on and off frequently, it could mean a problem with the thermostat.

Suppose your heating system is not responding to changes in the temperature you set on the thermostat. In that case, it could mean the thermostat is faulty.

Also Read:   How to stay warm without heat or electricity

6. You have higher heating bills

An unusually high heating bill could mean your furnace is not working as efficiently as it should be. If your furnace is old, and not producing enough heat, you’ll probably see an increase in your heating bills.

7. Yellow or no pilot light

The furnace will need to be warm to keep you warm. The heat produced by gas furnaces needs a burner. The burner requires an auxiliary light to operate. The pilot lights are tiny fires that stay active constantly, acting like the fire in the gas burner. 

Under normal operating conditions pilot light emits blue color. The flame should therefore have sufficient air for burning the fuel being consumed. Otherwise, there is some problem if the pilot light is yellow.

8. Frequent repairs

Getting your furnace repaired frequently, is one of the warning signs that there’s a problem with the furnace and it needs to be fixed. If you need furnace repair often, it’s crucial to find out why it’s breaking down so often and address the issue. It could also mean that you need to start thinking about furnace replacement.

9. Cold air

A furnace that isn’t heating your house may indicate imminent heating damage. There are several reasons for it but most of the time it is due to the blowing motors. When a blower fan fails, the furnace cannot blow air in a house with enough capacity. 

If the air blows off your furnace, the heat exchangers can cause problems with the pilot lights. It can lead to cold spots around a house. Those skilled technicians should take the opportunity to check the repair and make the necessary repairs.

10. You or your family is experiencing unexplained health issues

It might be your last thought, but furnace failure can damage your health and those around you. In the case of broken furnaces, it can cause carbon monoxide poisoning in homes. Symptoms can be headaches and flu-like aches/pains in some cases. 

Suppose your symptoms are mild or no flu. In that case, you can immediately call your health care provider for emergency repairs and maintenance. When the detector is activated the alarms sound a warning about poisonous gas in the environment.

If your heating system is not working here’s what you can do to troubleshoot it:

One of the most obvious is if your furnace is not kicking on at all. If you try to turn it on and nothing happens, it’s time to call in a professional to take a look.

Although it can be worrying if you think your furnace may be breaking down, try not to panic. There are several things you can do to troubleshoot the problem yourself before calling in a professional.

Check the thermostat

Is the thermostat on? it it on a high enough temperature to call heat from the furnace. check this then move on to the next step.

Does the furnace turn on?

Ensure that the furnace emergency switch is turned on and there’s power going to the unit. If that’s the case, you should check to see if the pilot light is on – if it’s not, there might be a problem with the gas line, or a gas leak if you have a gas furnace.

Check the circuit breaker

Try turning off all the breakers in your home and turning them back on one at a time to see if that fixes the issue.

When was the last time you change the filters?

Next, check the boiler or furnace filter and replace them if they’re dirty. Proper maintenance can prolong the life of your furnace despite of age.

It may be time to call in the professionals


If you’ve tried all these things and your furnace still isn’t working, it’s time to call in a professional. A Plumber is costly, but trying to fix it yourself beyond this point could be more expensive. 

In most cases, a broken furnace can be repaired or replaced. Still, it’s always best to catch the signs your furnace is dying as early as possible so that they don’t become too costly or challenging to fix. They’ll be able to diagnose the problem and suggest the best course of action for getting your heat back up and running again.

Final words

In my situation, I had a couple more service calls during that same winter my heat went out. Once spring came around, I replaced my boiler and have had good heat since and lower heating bills.

Thanks for reading to the end.

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