There’s a lot of debate about how long a furnace should last, with some suggesting as low as 10 years and others saying it’s as long as 30 or 40 years. Across the entire industry, manufacturers suggest the average is closer to 15 to 20 years for gas furnaces.
How long you can expect your furnace to last depends on several factors, all of which you have some control over. Consider these eight factors that affect how long your furnace will last, and how to know when it’s time for a replacement.
1. Furnace Make and Model
The elephant in the room that most people want to ignore is the equipment you decide to install. Like many other things in life, you get what you pay for when installing a new furnace. That means that saving a few bucks now for a less expensive model may shorten your furnace’s service life.
Conversely, going with the most expensive unit on the market may not give you the longest service life. Rather, getting the right furnace for your home is a lot like finding properly fitted shoes. Your technician will help you find the best option that will give you the longest service life and best performance for your particular situation.
2. Was It The Right Size?
Part of finding that perfect unit for your home is getting the right size unit. Furnace size refers to the heating capacity the unit offers, and you need to carefully match your size to your home.
You may read that you only need your home’s serviceable square feet to get the right size unit, but that’s only the foundation from which to work. Professionals use an algorithm called the Manual J calculation to determine how your home transfers heat. This accounts for variables like windows, exterior doors, type of insulation, number of occupants, and more.
Technicians use the results of this calculation to then find the perfect size unit for your home. Installing an oversized unit commonly results in short cycling. Undersized units cause extended heating cycles. In either case, your home never achieves your desired temperature, you consume a lot more energy, and you cut your unit’s service life.
3. How It’s Installed
If the system isn’t installed properly, it doesn’t matter whether you had a quality furnace or if it was the right size. Installing a furnace without proper training can leave the unit running less efficiently at the minimum, potentially damaging the furnace or causing gas leaks. This is why most manufacturers require professional installation by a certified technician to get the factory warranty. While you may notice major issues right away, it may be months or longer before you notice inefficient operation, cutting years from your new furnace’s service life.
4. How Often It Was Maintained
Proper maintenance is critical for keeping any mechanical system operating properly, including a furnace. The industry recommendation is annual professional maintenance, usually in the fall before the cold weather settles in for the winter.
There are several aspects of maintenance that may affect how your furnace wears and its service life. First are the airborne contaminants that build up in the system over time, slowly restricting the airflow through the system. Your technician will clean components like the heat exchanger and circulating fan to ensure the system has adequate airflow.
Further, components within the furnace will eventually wear out, causing strain and wear across the entire system as they perform suboptimally. Your technician will perform a series of tests as part of maintenance with the goal of finding minor performance degradation issues before they cut into your system’s service life.
5. How Minor Problems Were Dealt With
As just mentioned, small performance degradations can strain the entire system, further wearing many components. Many homeowners either intentionally or unintentionally ignore these minor problems, leading to extended excessive wear on your system. The result is more expensive repairs and years shaved from your furnace’s service life.
6. Average Temperature Setting
Your furnace will work to achieve whatever temperature you set on your thermostat. However, keep in mind that the more extreme that temperature, the more wear it causes on your furnace, especially during frigid weather. The U.S. Department of Energy, or DOE, recommends setting your thermostat to 68 degrees Fahrenheit to maximize your efficiency, minimize your energy consumption, and reduce the wear on your furnace.
You can further reduce the strain on your system and extend its service life by utilizing thermostat programs. Set the temperature back by 7 to 10 degrees while your house is empty with your family at work and school. This will keep it warm enough to prevent any freezing problems, but the DOE suggests it can reduce your annual heating costs by as much as 10%.
7. Indoor Air Quality
Poor indoor air quality can significantly increase your furnace’s operational strain. Poor air quality translates into air filters that clog more quickly and more contaminants settling into your furnace and air ducts. These collectively choke your system and cause increased heat retention. Not only does this increase your operational cost, but if left long enough it can even cause damage like a cracked heat exchanger. Avoid this by routinely changing your air filter and finding solutions to manage your indoor air quality.
8. Household Airflow
In addition to airflow through your system, the airflow around your home is also critically important for how your furnace performs. Proper airflow allows the system to create adequate circulation throughout your home to cause even heating. Household airflow is inadvertently interrupted by blocking or closing vents, including putting furniture in front of or over them. Additionally, closing interior doors further interrupts household airflow. The resulting lack of circulation causes hot and cold areas in your home as the heat comes from some vents without moving into the rest of your home, ultimately leading to longer heating cycles and more system wear.
When To Replace Your Furnace
Beyond your furnace simply not turning on or producing heat, there are some factors that signal a replacement is on the horizon. The foundation of all of these is the unit’s age. Once your unit reaches 10 years of service, it’s time to start planning on a replacement, giving you several years to budget and research your options.
As your furnace continues aging, keep a close eye on the amount you’re spending on repairs. Combine the total repairs for the last two seasons and multiply it by the age of your unit. Once this exceeds the cost of a new unit, it’s time for a replacement.
Also, keep an eye on your heating costs. Older furnaces tend to lose efficiency over time, so a marked increase in fuel or energy consumption indicates your system isn’t running as efficiently as it was. A technician will help you determine if the cause is repairable or if it warrants a new unit.
For more than 25 years, Beyer Air Conditioning & Heating has been the residential home comfort provider of choice around Selma. Our NATE-certified technicians offer air conditioning and heating maintenance, repair, and installation along with indoor air quality solutions and duct cleaning and repair. Call to schedule your consultation with one of our trusted technicians to evaluate whether it’s time to replace your furnace.