Unfortunately, at 20 years, no furnace is running as efficiently as it once was. For starters, HVAC repair experts confirm that any furnace that has been in use for 20 years is nearing the end of its lifespan. The components of a 20-year-old furnace suffer a lot of wear and tear over the years.
An 18 to 20-year-old furnace will measure more than 20% inefficiency, meaning 80% of the power (gas or electricity) goes to heating your home, while 20% is wasted. A new high-efficiency furnace will read between 90-95 AFUE, meaning 90-95% of the power used goes to heating your home, and only 5 – 10% is wasted.
Older furnaces need annual check ups. Main thing is the heat exchanger getting a crack, which could lead to fire or carbon monoxide poisioning. 20 years is a good time to start considering a new one but not essential, if the tech that comes to clean the burners sees an issue they will point it out to you.
Most gas furnaces start to decline in efficiency once they hit the ten-year mark. Although a well-maintained gas furnace can last up to 20 years, they won't heat your home as well as a newer model and are more prone to breaking down.
So long as it is working and is affordable to use, there is no reason to replace your 20-year-old HVAC. But since it is a very old system, you should be prepared to replace it. They seem prone to fatally breaking down only on the hottest or coldest day of the year.
For instance, a 20-year-old unit may have a 10- or lower SEER. Replacement: New AC units are significantly more energy-efficient, with SEER ratings ranging from 14 to 25. A higher SEER translates to lower energy consumption and lower utility bills.
In general, most HVAC systems will last 15 to 25 years, but depending on the type of system and other contributing factors, that estimate can be highly variable. Even with HVAC maintenance and regular repairs, eventually, even the best boilers, furnaces, heat pumps, and air conditioners today will run their course.
1. Replace your oil furnace or gas furnace as it approaches the end of its furnace life expectancy. Furnace life expectancy ranges from 15-30 years on average. A well-maintained furnace can last 15 to 20 years with proper care.
Older furnaces may have an annual fuel utilization efficiency (AFUE) rating of just 60% to 80%. This means they waste 20% to 40% of the energy on the flue gases. According to the Department of Energy, efficient furnaces have AFUE ratings as high as 98%. This means they waste just 2% the input energy on the flue gases.
Older models are simply not as efficient at converting fuel into heat as modern, high-efficiency furnaces. This inefficiency means your furnace must work harder and consume more fuel to maintain your desired temperature, resulting in higher energy bills.
Installation Entails More than Just the Furnace
For a gas-powered furnace, a contractor must set up a gas connection and vent. Installing an electric furnace requires running wiring, adding a circuit breaker, or perhaps updating an electrical panel. Holes are often drilled for pipes and wires.
At what age should a furnace be replaced? Generally, a furnace should be considered for replacement after about 15 to 20 years. However, the exact timing can vary based on the furnace's maintenance history, performance, and any increase in the frequency and cost of repairs.
Even a slightly undersized furnace will accomplish the job the majority of the time. Taking things down a few sizes will more than likely solve some of your common heating problems like too high of a utility bill while half of your house is blazing and the other half is an icebox.
Repair: If your furnace system is less than 15 years old and the cost of repair is less than half the cost of replacement. Replace: If your furnace system is more than 15 years old and requires a costly repair to maintain efficiency.
New furnaces are designed with advanced heat exchangers and variable-speed blowers that optimize the heat distribution process. This means that the warm air is evenly distributed throughout your home, eliminating cold spots and ensuring consistent comfort in every room.
High-efficiency furnaces have an AFUE of 90 percent or more. If you have a furnace with an AFUE of 80, that means 20 percent of your heat is being lost. At a 90 AFUE, only 10 percent of your heat goes up the chimney, so to speak. Some older furnaces from the 1970s or 1980s had an AFUE of only 60 to 65 percent.
Different heating systems are going to impact different energy bills. If you have a heat pump, it's going to increase your electricity bill, whereas if you have a gas furnace, it's going to impact your gas bill. The type of system can also determine how energy efficient it is.
A natural gas furnace can last 15+ years, especially if it receives an annual tune-up and its filter is replaced regularly. Because our furnace technicians see a decrease in reliability, performance and efficiency in furnaces exceeding 15 years of age, we generally recommend getting a new furnace at the 15-year mark.
Are old furnaces dangerous? Unfortunately, yes. Since many old models run on oil or gas, there's always the risk of their fuel catching fire or leaking into your home. If left unaddressed, such malfunctions can be life-threatening.
You'll be looking at a different cost depending on the location of the furnace, the size of your home, and the type of furnace. But the average cost per unit can range anywhere from $2,672 - $6,575. The national average is $4,820 - $9,350 for a full furnace installation.
According to HomeGuide.com, the average cost to replace the HVAC units is $5,000 to $11,000; to replace the units with ductwork runs between $7,000 and $16,000 in total.
For example, the seer rating of 20-year old air conditioner systems is likely to be between 10 to 12 whereas a newer unit purchased this year would have an average SEER rating of 15 or more.
Life Expectancy of Common Heating Systems
Furnaces: 15-30 years. Boilers: 15-30 years. Heat Pumps: 15 years. Active Solar Heating: 20+ years.