How Often Should I Replace My Furnace?

The service life of your furnace is an important factor in budgeting for your home. After all, you can plan for the inevitable so you are not faced with a crisis. However, there is a big difference in planning for a replacement in 10 years versus 20 years. Learn how to determine the expected service life of your furnace, the variables affecting its life and how you can extend it.

Manufacturer’s Goal Service Life

All manufacturers have a goal in mind for how long their furnaces will last given good operating conditions and proper maintenance. These time frames are dependent on many variables and expressed as an average among all installed units.

In addition to external variables, you have to consider the unit itself and the parts used within it. These parts make the saying true that you get what you pay for, even with furnaces. That does not mean that the most expensive units will last twice as long as the cheapest. However, it may be the difference between a system lasting 10 years versus 15 years.

When properly maintained, forced air and high-efficiency condensing gas furnaces have an average service life of 15 to 20 years. Kerosene furnaces have a little longer service life with about 25 years being average. These numbers assume proper installation, routine maintenance and good air quality.

Installation Considerations

Proper installation is critical to having a furnace fulfill its potential service life expectancy. The company Energy Star estimates that more than 50% of furnaces are improperly installed.

When a furnace is improperly installed, various problems are created. There are obvious safety issues that can arise due to working with combustible fuel and toxic exhaust. However, on the milder side, improper installation can create excessive vibration. This vibration loosens some components, causing additional strain on the system.

This is why many manufacturers require that their systems be installed by an authorized installer. This authorization designation means the manufacturer agrees the installer knows what they are doing. For you, what matters is that your warranty will be protected, and you will have fewer repairs over the first few years.

Proper Maintenance Routine

Next to proper installation, regular maintenance is critical to keeping your furnace running properly. Just as with authorized installers, many manufacturers condition the warranty on their systems to receiving routine maintenance from qualified professionals.

The reason they have this focus is because of the effect the maintenance has on the system. During the course of normal operation, a furnace generates vibration, which loosens mounting bolts and screws. It also collects air contaminants on sensitive components like the heat exchanger and circulating fan.

The problem with all of these factors is that they add strain to your system as it runs. This strain manifests as added resistance on the electrical components. Extra resistance means each of those components creates more heat in areas where that heat should not be. Additional heat causes wear on electrical components and wiring.

During a proper maintenance visit, a qualified technician will clean the sensitive areas, lubricate the fan bearings and tighten the mounting screws and bolts. The technician will also look for signs that components are not working properly. This allows you to replace them before they become problems.

In addition to routine professional maintenance, be sure to change your air filter regularly. Most units use filters which should be changed every 30 to 90 days. Check your filter monthly and replace it when it starts showing signs of being overly dirty. In addition, try vacuuming the intake side of the filter to help keep it working longer.

Your Home’s Air Quality

Air quality is a major contributor to how your furnace operates and how long it lasts. When you have poor air quality, there are more contaminants to clog components like your filter, heat exchanger and circulating fan. When these get clogged, your system experiences excessive stress, which reduces the service life.

Affecting your air quality is your home’s humidity. The EPA recommends maintaining a relative humidity of between 30% and 50%. Anything lower causes airborne contaminants to stay in the air longer. A higher humidity encourages the growth of some biological contaminants.

Also affecting your air quality are the contaminants collected in your ducts, such as dust, dirt and biological particulates. As your system runs, the passing air picks up some of these particles and recirculates them into your home. To avoid this, plan to have your ducts professionally cleaned every three to five years.

How Well Air Flows Around Your Home

Not only do you need air to flow freely through your system, but you also need air to move well throughout your home. Of course, you can use ceiling fans to assist this effort; however, that may not be enough.

If air cannot flow freely from your vents and freely into your return vent, your system will not heat your home properly. Check to make sure your vents are properly set to maximize air movement throughout your space. Also, check to ensure all your vents have at least six inches of clearance around them to ensure air can move properly. Paying attention to this should help heat your home more evenly and reduce your overall heating expenses.

Age and Model

Buying the most expensive furnace on the market does not necessarily mean it will last the longest. However, it does mean that lower-cost systems are generally made with components of lower quality, and those won’t last as long. When a component begins malfunctioning, the entire system experiences more strain, reducing its service life.

What’s more, the time period when your unit was manufactured will play a role in how long it will last. Generally speaking, newer models tend to last longer than older models. A unit manufactured 10 years ago may be expected to last about 15 years, whereas a model manufactured today may last 20 years.

Professional technicians will be able to look at your furnace and tell you the age of your current system. Armed with this knowledge, they may be able to give you a general idea of how long they have seen similar models last.

Signs You May Need a New Furnace

How do you determine if it is time to replace your furnace or continue investing in repairs? First, look at your annual repair costs. If your system is nearing the 15-year mark, use the 50% rule for repairs. If your annual repair costs or pending repair costs are nearing 50% of the replacement cost, it may be a good time to replace your unit.

If your unit is more than 15 years old right now, you may want to begin proactively planning to replace your system. Doing so will reduce ballooning repair costs, including emergency repair visits when the system is strained. It will also help lower your heating costs due to the improved efficiency of the newer unit. If efficiency is a top priority, you may want to evaluate geothermal as an option when you replace your system.

Hoff Heating & AC provides expert furnace installation, maintenance and repairs for the O’Fallon, MO, area. Since 1983, residents and businesses alike have relied on our award-winning team for a complete range of heating, cooling and air quality services. We also handle geothermal. Give us a call today to schedule a consultation with one of our technicians to evaluate the remaining life of your furnace.