Asking when to replace a boiler is a lot like asking when to replace a car. Does it receive proper maintenance with regular oil changes? How many miles is it driven each year? What kind of engine does it have?
As with most questions, there’s no simple answer. However, examining the main factors that impact boiler longevity can go a long way to simplify the answer.
To begin, understand that conventional cast iron boilers like the U.S. Boiler Company Series 2, X2, MPO-IQ, ESC and ES2 will generally last longer than high efficiency, condensing boilers. This holds true across all boiler brands.
This is simply the nature of all machinery. Higher performance typically yields a shorter lifecycle. It’s like comparing the diesel engine in a semi-truck to the gasoline engine in a sports car. The truck engine will last for a lot more miles because it’s built with heavier components and operates at lower RPM.
Boilers are no different.
How long should a cast iron water or steam boiler last?
When properly installed and maintained, homeowners can roughly expect a conventional cast iron water boiler to last 20 or more years.
There are plenty of examples of cast iron boilers lasting more than 50 years, but this is not typical.
How long should a high efficiency, condensing boiler last?
High efficiency gas boilers, like U.S. Boiler Company’s Alta, Alpine, and Aspen, have an expected lifecycle of 15 or more years when properly installed and maintained.
Beyond the type of boiler installed, there are many factors that impact the length of time that the unit will be in service.
Proper installation
It’s critical that the boiler is installed correctly to begin with. Hiring a professional, licensed heating contractor is worth every penny. It’s important to understand that a boiler is just one component among many in a hot water heating system. Systems also include pipe, valves, pumps, radiators, etc.
While the boiler’s job is to create heat, it’s not immune to errors that can be made while piping the mechanical system. Correct placement of circulators, zone valves, expansion tanks and venting is vital for the longevity of a boiler and heating system.
If the components of the heating system are not installed correctly, the boiler cannot operate as intended by the manufacturer. In fact, most boiler repairs and issues are the result of improper installation. A boiler that’s not installed correctly will not last as long as one that is.
Correct sizing
Selecting a boiler that is properly sized for the needs of the home is also critical to longevity. Many of the boilers installed in the United States are too large for the spaces that they’re heating. This occurs less frequently than it did in the past, but it’s still an issue. More often than not, an oversized boiler is the result of an installer that did not complete a comprehensive heat loss calculation.
A boiler that’s too large for the home will “short cycle,” meaning that it will fire up and shut off quite frequently. Firing up and shutting down quickly is much harder on the unit than simply running for long periods of time, and results in unnecessary wear and tear.
Imagine two drivers in two different cars driving down the highway. The first driver (properly sized boiler) sets the cruise control to 65 MPH. The second driver (oversized boiler) alternates between flooring the accelerator and reaching 120 MPH, and stomping on the brake pedal to come back to a standstill. Both vehicles arrive at the destination at the same time, but driver number two used far more fuel and put more wear on the vehicle than driver number one.
Maintenance
The importance of proper annual maintenance conducted by a professional heating technician cannot be overlooked.
All machinery needs to be maintained. Specific to boiler systems, heat exchangers should be cleaned annually to reduce corrosion. Maintenance is also important for the operating efficiency of a boiler. The cleaner the heat exchanger, the less energy needed to heat the home.
While a technician is servicing a boiler, they’ll also check for any small leaks throughout the system, check the boiler control for errors, and be sure that the boiler is running as intended.
Length of heating season
A boiler installed in Maryland is likely to last longer than the same boiler installed in Alaska. Longer, colder winters mean more runtime over the course of a heating season.
Compare a vehicle owner who drives 15,000 miles each year to one that only drives 7,500 miles. The second driver will likely get more years out of the same car. This comparison is one more reason that there is no hard-and-fast rule for how long a boiler will last.
Boiler quality
You get what you pay for. A quality boiler is assembled with better components and a higher level of attention to detail, not to mention a better design.
The best boiler manufacturers are also committed to properly training the contractors who install them. All of this lends itself to providing heating systems that will operate efficiently for a long time.
Rest assured that a boiler system is the longest lasting, most comfortable way to heat your home. Then, carefully consider the boiler you purchase and who you hire to install it. Boiler systems are a sizeable investment, so take the decision seriously!
Once you’ve selected a heating contractor, explain to them what is most important to you. That may be comfort, efficiency, budget, fuel type, service life, etc. After that, trust the professional to determine which boiler is best suited for your heating system.
You can also do some research on boiler options here: https://www.usboiler.net/choosing-the-right-boiler.html
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by Dan Vastyan