We often take our furnace for granted, but it plays a vital role in maintaining the comfort and safety of our home. It is essential to keep up with regular maintenance and repairs and replace your furnace when necessary. Doing so can save you money in the long run by preventing costly repairs and avoiding a system breakdown during colder months.

However, how will you know if your furnace needs repairs or is ready to be replaced? 

This blog will discuss the things you should consider, whether your furnace needs repairing or replacement.

1. Age of the Furnace

Knowing the age of your furnace is essential to understand when it may need to be replaced to maintain a safe, efficient, and comfortable home. In most cases, furnaces last between 15 and 20 years. 

One way to find out the age of your furnace is by looking for the serial number or model number on the unit itself. Typically, the earlier models will have a six-digit code imprinted on the furnace, whereas more recent models may have a 10-digit code starting with “95” or “96”. Knowing the exact model and serial number can help you identify your furnace’s age. 

2. Heating Levels

If you have noticed that your furnace is taking longer to heat up or is not reaching the desired temperature, it could be an indication that the system needs either a repair or a replacement. This could be due to factors such as the age of your furnace or lack of maintenance or upkeep.

First, inspect your furnace’s filter and air ducts to make sure it is clean. Dirty filters and air ducts can affect airflow and make the furnace run less efficiently. 

Next, ensure all vents in your home are free from obstructions such as furniture and curtains, as this will ensure air circulates freely for maximum comfort. Also, check for any gaps around windows and doors, which may be causing cold air to enter your home and lower the temperature inside.

If these simple steps do not resolve the issue, then something may be wrong with the furnace itself, and it must be replaced. 

3. Strange Noises

Any banging, popping, or squeaking sounds from the furnace should be investigated immediately. It is essential to attend to these issues as soon as possible as they could indicate a more serious underlying problem with your heating system. 

These unusual noises may be caused by a buildup of dust and debris in the vents and fan blades or indicative of worn-out metal components in older furnaces. The noise could also be caused by a fan motor that has gone bad, a loose belt, failing bearings, inadequate lubrication, or blocked air ducts.

4. Increase in Utility Bills

If you’ve recently noticed a spike in your monthly energy bills, then it’s time to check on the efficiency of your furnace. A malfunctioning furnace can cause energy costs to skyrocket due to its inefficient use. To get your furnace fixed or replaced, you’ll need to call an HVAC technician to assess the condition of your unit.

When the technician arrives, they will inspect the furnace for any signs of damage. If the furnace is beyond repair, they may suggest that a replacement is the best option to save money in the long run. 


Understanding when your furnace needs repair or replacement is essential for determining the most cost-effective solution and guaranteeing a long lifespan. With all of this in mind, if your furnace shows signs of age, consider upgrading it with a newer, more efficient model.

If you are considering an HVAC duct cleaning in Birmingham, Al, for a more efficient heating system, look no further than Duct Doctor Birmingham. Both commercial and residential properties benefit from our air duct cleaning services. Contact us today!