Furnaces have wide-ranging efficiency ratings, measured by the Annual Fuel Utilization Efficiency (AFUE) ratio. This considers how much heat the unit produces versus how much is lost with the exhaust. No matter what your system’s AFUE rating is, it may not run optimally throughout its entire service life, so it’s something you should monitor regularly. Consider these 12 signs that your furnace’s efficiency may be lacking.
1. High Energy Bills
First, consider your heating bills, especially how much fuel and electricity you consume. Watch for spikes from one month to another that don’t appear to correlate to colder weather. Additionally, compare your consumption against the same month in the year prior. Unexplained spikes in year-over-year consumption may signal reduced efficiency.
2. Long Heating Cycles
Heating cycles will vary depending on the type of system you have. Standard-efficiency models with an AFUE rating of 80% to 89% will generally have heating cycles that run 10 to 15 minutes and usually have two or three cycles per hour. If your system is running cycles lasting more than 15 minutes, it’s likely because it’s not running as efficiently.
High-efficiency systems with modulating burners and variable-speed circulating fans may run nonstop but at a lower capacity. If it’s frequently running at a higher capacity, it’s indicating the unit is working to raise the temperature rather than maintain it.
3. Uneven Heating
One of the keys to heat circulation is air movement within your home, which is also a major factor in your furnace’s efficiency. When your house isn’t heating evenly, it could signify an issue with the circulating fan drawing and pushing sufficient air. These problems may start with something as simple as a dirty air filter. It could also be an airflow restriction within the system or it may mean the circulating fan isn’t spinning at the proper speed.
4. Your Furnace’s Age
The average gas furnace has an expected lifespan of 15 to 20 years when it’s properly maintained. As the unit ages, it will slowly lose some of its efficiency as the internal components wear and stop working optimally. Merely having a system that’s older than 15 years may mean that it’s not working as efficiently as it once did even if it’s received annual maintenance. Further, furnace technology evolves, and the minimum standards are constantly improving, so newer furnaces will likely have a better efficiency rating than the outdated unit in your home.
5. Your Thermostat Is Outdated
Like the rest of your furnace, your thermostat will eventually wear out. Most modern digital thermostats have an expected lifespan of 10 to 15 years. As it gets older, the sensors may not register the temperature accurately, resulting in extended heating cycles. Furthermore, if your thermostat doesn’t have programs that match your lifestyle, you’re likely not achieving optimal heating efficiency, even with a new thermostat. Consider upgrading to a smart thermostat the next time you replace it to make it easier to achieve peak efficiency.
6. You Have Blocked Air Vents
Your furnace heats your house by pushing warm air through the supply vents, but it has to circulate through the rest of the residence. It does this by creating positive pressure at the supply vents and negative pressure at the return vents. Air seeks to stabilize the pressure, so the positive pressure moves toward the negative pressure areas. Supply vents that are blocked or closed inhibit positive pressure and keep the air from circulating. Without proper circulation, your system may run longer cycles while the air near the thermostat remains cooler.
7. You’ve Neglected Routine Maintenance
Furnaces require routine maintenance to get the longest service life and optimal efficiency for the heater. Neglecting maintenance allows electrical connections and mounting hardware to loosen. Contaminants can also build up inside, such as on the heat exchanger and circulating fan. Small problems may evolve into larger ones. If you can’t remember the last time your equipment received maintenance, it’s likely operating at reduced efficiency.
8. Yellow or Flickering Burner Flame
When you look at the flame in the furnace through the window, it should look steady and appear as translucent blue. A yellow or orange flame indicates the fuel isn’t burning completely, which means it’s not producing as much heat as intended. Additionally, a flickering flame may indicate an issue with fuel flow or proper ventilation in the system, both of which negatively impact the heat your unit produces and, therefore, your heating efficiency.
9. Frequent Repairs
Your furnace will eventually need some repairs as it ages and components wear out. However, a system that requires frequent repairs may indicate it’s not running efficiently, especially if you see multiple repairs needed in a single season. Heaters that aren’t running as efficiently as designed experience excessive wear, causing components to wear out prematurely.
10. Unusual Sounds and Odors
When running properly, your furnace should only make quiet sounds, like a few clicks, the whoosh of the burner lighting, and the whir of the circulating fan. Furnaces shouldn’t emit odors, especially after the first cycle of the season.
Unusual sounds like clanking, banging, screeching, and rattling all indicate problems and inefficiency in the system. Likewise, unusual odors such as burning, chemical smells, or musty aromas indicate issues within the unit, which also create inefficiency.
11. Significant Icing on Your Roof
Winter alone brings the chance of icing of roofs. However, with a furnace experiencing efficiency problems, that icing can become significant, especially around the exhaust vent cover. When the system isn’t running efficiently, the exhaust may be hotter than normal coming up through the flue and out the vent. Hotter exhaust usually contains more moisture, which immediately condenses and freezes when it hits the frigid outside air. Common efficiency issues that allow this may include blocked or closed vents, airflow restrictions like a dirty air filter, problems with the circulating fan, or a dirty or corroded heat exchanger.
12. Condensation on Your Windows
The air around Southwestern Idaho is usually fairly dry, especially over the freezing winter. However, there are plenty of things inside your home that will create humidity, such as bathing, cooking, and doing laundry. A furnace that’s running inefficiently may fail to draw out the humidity in the heating process like it should. The most common result is condensation forming on cool windows. Possible efficiency issues that may cause excess humidity can include restricted airflow, especially at the air filter, inefficiently burning fuel, a clogged condensate drain, poor ventilation, or possibly a malfunctioning humidifier if you’re using one.
Nearly 40 years ago, people around Garden City found a partner they could trust when Perfect, Plumbing Heating & Air started providing home services. Our expert team provides air conditioning and heating maintenance, repair, and installation together with indoor air quality solutions. We also handle residential plumbing services like plumbing and pipe repair, water heater installation and repair, gas line installation and repair, sump pump installation and repair, water filtration and softener installation, and drain and sewer inspection. Call to schedule an appointment with one of our award-winning technicians today.
