When should I worry about my furnace?

Author: Susie Little  |  Last update: Monday, February 16, 2026

Your furnace will need an emergency furnace repair if you start hearing strange noises while it's running. A clanking, whistling, or rattling sound is not normal and means something is wrong with your unit's components such as the motor or fan. However, the specific problem will depend on the noise produced.

When should I be concerned about my furnace?

Pilot flame color changes

A yellow flame is a clear sign that the gas is not burning properly. Dirty or partially blocked systems can produce this. It's also another sign that a call to your trusted HVAC contractor is needed to save money and keep you a bit safer.

How do I know if my furnace needs replacing?

Common warning signs of an ailing furnace are frequent repairs, rising energy bills despite a constant temperature, unexplained noises (such as popping, banging or screeching), and dust or soot build-up around registers. A furnace lasts approximately 15 years, depending on maintenance and other factors.

What is considered a furnace emergency?

Losing your home's heating is considered an emergency when it's 40 degrees or colder outside. Within just a few hours, a lack of heat can cause indoor temperatures to become uncomfortable and ultimately unhealthy, especially for the young and elderly or those with underlying health conditions.

What is the typical lifespan of a furnace?

The Average Furnace Lifespan

A well-maintained furnace can last at least 15 to 20 years, but completing annual maintenance and being diligent with repairs can extend its life even longer.

Top 5 Furnace Problems and How to Fix Them

What is considered old for a furnace?

If your furnace is over 20 years old, it might be time to consider a replacement, especially if you're experiencing issues like poor air quality, frequent repairs, or high energy bills.

How often should a furnace be serviced?

Ideally, you would have your furnace serviced at least once a year. To elaborate on that point, you should have your furnace serviced at least once a year to catch any problems early on and to keep your furnace in top condition. Professional maintenance and cleaning provide many benefits, which we'll cover next.

Who to call when your furnace goes out?

For your safety, only a licensed professional is qualified to fix this furnace problem, so contact you local HVAC technician for your furnace repair.

At what temperature should you put your furnace on emergency heat?

However, what happens when it is too cold outside for the air to be pulled in and heated normally? This is where emergency heat comes in. Typically, this setting on your thermostat kicks on when the temperature is anywhere between 30 to 35 degrees Fahrenheit.

How cold can a house get without heat?

How cold can a house get without heat overnight? The time of day your heater goes out impacts how long the house stays warm. Indoor temperatures go down faster at night, so if your furnace stops overnight, you can expect a quicker decline. This can be as much as 15 degrees Fahrenheit before morning.

How much does a new furnace cost?

You should expect to spend between $3,800 and $12,00 on a new furnace, including both the unit and installation costs. Factors influencing the price include the type of furnace (gas, electric, or oil), the unit's efficiency rating, and the complexity of the installation.

How do you know if your furnace is dying?

Signs your furnace is going out include inconsistent heating, strange noises, frequent short cycling, a yellow burner flame, and higher heating bills. If it's over 15-20 years old or requires frequent repairs, it may be time for a replacement.

What is a common failure for a furnace?

One of the most common furnace problems is a malfunctioning thermostat. A sure sign your thermostat isn't working properly is if your fan is constantly running. This will cause your thermostat battery to run, and cause your furnace to work inefficiently.

How do I know when my furnace needs replacing?

Five signs you need to replace your boiler or furnace
  1. Uncomfortable or uneven temperatures. An aging heating system will struggle to heat your home evenly and consistently, especially on colder days. ...
  2. Unusual sounds. ...
  3. A yellow flame. ...
  4. Rust or other corrosion. ...
  5. Over 15 years old.

What time of year is the cheapest to replace a furnace?

For people taking a proactive approach, doing a furnace replacement during the “shoulder seasons” of spring and autumn may offer lower prices, shorter lead times, and a better selection of products and service appointment availability.

How do I tell what's wrong with my furnace?

How to Troubleshoot a Furnace: 7 Steps to Finding a Solution
  1. Inspect the Thermostat. ...
  2. Change the Furnace Filter. ...
  3. Confirm the Furnace Is Getting Power. ...
  4. Make Sure the Circuit Breaker Isn't Tripped. ...
  5. Check the Vents for Blockage. ...
  6. Make Sure the Front Panel Door Is Secure. ...
  7. Call a Professional.

What temperature should my furnace be putting out?

The DOE recommends a temperature range from 68 degrees up to 72 degrees. If elderly persons are residing in the house, many sources recommend higher temperatures — up to 78 degrees.

What is considered a heat emergency?

Heat emergencies are of three types heat cramps (caused by loss of salt), heat exhaustion (caused by dehydration) and heat stroke (shock). Remove the victim from the heat and have him lie down. Apply cool compresses, elevate the feet, drink fluids and use a fan to blow cool air. Get medical help if needed.

Do heat pumps automatically switch to emergency heat?

The system automatically switches to emergency heat at these extremely low temperatures to ensure your home stays warm. This transition is seamless, but you may notice a slight increase in your energy bill during these periods.

How much does it cost to have someone come check your furnace?

A furnace inspection costs an average of $80 to $100. Your cost may increase if more furnace repairs are needed, or based on the specifics of your HVAC system. If detrimental issues are uncovered, you'll be quoted for the repair or potential replacement of your HVAC equipment.

What shuts down a furnace?

One of the most common causes of a furnace shutting off unexpectedly is low airflow. If your furnace keeps turning off, check for issues such as: Dirty Air Filters. A clogged filter restricts airflow, causing the furnace to overheat.

Does homeowners insurance cover furnace?

Your base homeowners policy will cover many types of damage to your furnace. An extra endorsement known as Equipment Breakdown Coverage (EBC) will give you additional coverage for certain types of mechanical or electrical failure.

How to tell if your furnace needs cleaning?

Let's look at some of the signs that furnace cleaning should be performed sooner rather than later:
  1. High energy bills.
  2. Reduced heating efficiency.
  3. Unusual noises/frequent cycling.
  4. Funny smells.
  5. Increased allergies or respiratory issues.
  6. Dirt, debris, or clogged filters.
  7. Yellow furnace pilot light flame.

How much does a furnace cleaning cost?

The cost of furnace cleaning can vary depending on several factors, but on average, it ranges from $60 to $400. While this might seem like a wide range, the final price will depend on things like the size of the furnace, its condition, and the specific services included in the cleaning.

How often should I clean air ducts?

Experts advise having your air ducts cleaned every 2 to 3 years to prevent many maintenance and health problems before they start. However, homes with pets or children with allergies should have their air ducts professionally cleaned more frequently than the recommended average.

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