Boiler Efficiency: Here’s What You Need To Know About AFUE And Energy Savings


If you have an older boiler – even though it still may be working well – much of your fuel may be going out the chimney or flue. Older boilers (especially those converted from coal to oil or gas) are often quite inefficient. However, modern boiler efficiency is at an all-time high, with newer models having efficiencies that go upwards of 90 percent Annual Fuel Utilization Efficiency (AFUE). Homeowners who choose high AFUE-rated boilers will see significant energy savings.

AFUE Ratings for New Systems

AFUE is a government ratings system that provides a level playing field for consumers to evaluate how well a boiler uses fuel. If a boiler is rated 70 percent AFUE, the remaining 30 percent is pure waste, which, in the past, was deemed efficient. Considering that any loss is money wasted, a unit that uses only 70 percent or less energy to generate heat gives sticker-shock a whole new meaning. And while many low-efficiency boilers are still in operation today, today’s minimum standard for production of new systems is 80 percent, and Energy Star-rated equipment performs even higher than that.


If, in our tight economy, you don’t want the expense of a new boiler, consider retrofits options. Certain aspects of your boiler can be modified to increase your current boiler’s efficiency. Often, a retrofit will save enough in increased fuel efficiency over the course of a few winters to pay for the upgrade. It is best to have your current boiler assessed to see if a retrofit would be more cost-effective than a new unit.

New Models

New boilers benefit significantly from advances in efficiency. In years past, boilers were often over-sized. Today’s models are sized specifically to a home’s needs, while these smaller, more compact models can reduce fuel consumption even more. Also, sealed-combustion boilers pull outside air into the exhaust system, instead of pulling indoor heated air out the flue – saving homeowners even more.

If you would like more information on increased boiler efficiency, contact the expert staff at Rodenhiser. We can explain the new AFUE ratings, inform you about retrofits or show you how to save in fuel.

Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems).  For more information about boiler efficiency and other HVAC topics, download our free Home Comfort Solutions Guide.

Rodenhiser Plumbing, Heating and Air Conditioning serves the Route 495/128 area of Massachusetts. Visit our website to see our special offers to get started today!

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