Many people don't know the difference between a boiler and a hot water heater. A water heater is a large tank that heats water, while a  boiler can heat water that is used to bring heat to the home and heat the water. There are  boilers that  can heat the water to the point it turns into steam.   boiler controls_s

A boiler is a closed vessel in which liquid such as water is heated.  Despite the name, the water or other liquid does not always boil. The heated or vaporized fluid exits the boiler for use in various processes or heating applications, including water heating, central heating, boiler-based power generation, cooking, and sanitation.

Modern boilers are more efficient than older models for several reasons. Newer models are  condensing boilers. They achieve high efficiency by condensing water vapor in the exhaust gases.  By recovering the latent heat in the exhaust which would have been wasted, the boiler much more efficient. 


As with any heating system, it is important to maintain the equipment. An annual inspection by a  professional will help you determine the  condition of your boiler. If your boiler is a high-efficiency model, it is especially important to have a tune-up done every year after it is installed.

Life Expectancy
Your boiler won't last forever and you may notice it is less efficient as it gets older. The average lifespan for a cast iron boiler is 30 years, while a high-efficiency boiler will last about 15-20 years.

Signs of aging to watch for:

  • Calcium or green deposits by the pumps or joints in the pipes
  • Rust on the metal  vents
  • Adding  water more than once per season to maintain boiler pressure
  • Noise in the radiators or pipes while the boiler is running
  • No heat in the radiators or very little heat in the upper floors
  • Carbon monoxide readings are high

AFUE is the ratio of annual heat output of the boiler compared to the total annual fossil fuel energy consumed by a boiler.  An AFUE of 90% means that 90% of the energy in the fuel becomes heat for the home and the other 10% escapes up the chimney and elsewhere.

An all-electric boiler has no flue loss through a chimney. The AFUE rating for an all-electric boiler is between 95% and 100%. Their high efficiency does not make them practical in some parts of the country due to the higher cost of electricity.

Older boiler systems had efficiencies in the range of 56% to 70%, while modern boiler  systems can achieve efficiencies as high as 98.5%, converting nearly all the fuel to useful heat for your home.


Replacing an older boiler may not be possible for financial reasons.  Boilers can sometimes be retrofitted to increase their efficiency. These upgrades improve the efficiency of otherwise sound, boiler systems. Before starting a retrofit, the costs of a retrofit should be carefully weighed against the cost of a new boiler, especially in older models that may need to be replaced in a few years.

Boiler Replacements

If the boiler is old, inefficient, frequently breaking down or significantly oversized, the easiest solution is a replacement. Coal burners that were converted to oil or gas are prime candidates for replacement, as well as gas boilers with pilot lights rather than electronic ignitions.  If it’s a planned or unplanned boiler replacement, it is very important to match the boiler size to the home.

It’s important to know that you should never attempt to repair a boiler yourself.  Ohio Plumbing & Boiler is the Columbus and Central Ohio leader in residential, commercial and industrial boiler repair, installation and service. We can help you find the solution that is best for your home and your budget. 

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 • Boiler Repairs - All Makes
 • Boiler Installation - All Makes
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 • Pressure Vessel Repairs/Replacement
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 • Condensate, Expansion & Storage Tank Repairs/Replacement
 • D.A. Tank Inspections/Repairs
 • Blowdown Separators and Tanks
 • Combustion Efficiency Testing 
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 • Burner Replacement
   & more.
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Topics: modern boilers, boiler tips, condensing boilers