AFUE: An Important Efficiency Measure, But Not the Whole Story

Posted: December 21, 2017

Boiler heating system

You probably know the yellow stickers on your boiler are important. But do you mean what they mean?

The most important number on that sticker is your boiler’s AFUE – or Annual Fuel Utilization Efficiency – rating. AFUE is kind of like miles per gallon in your car – the higher the number, the more efficiently it runs. A boiler with an AFUE rating of 80, for example, converts 80 percent of the fuel it receives to supply heat – the other 20 percent is lost out of the chimney.

The problem is that boiler efficiency is a more complicated proposition than simply measuring its AFUE performance. To understand “real world” boiler efficiency, you need to consider other factors.

Real-world boiler efficiency

Get this: you could spend as much as $800 more on fuel for your boiler compared to a neighbor who owns a boiler with a nearly identical AFUE rating. How is that possible, you ask? Because AFUE only measures energy lost to the chimney – which means it doesn’t take into account such factors as:

  • Jacket loss – Heat lost when it escapes your boiler as it sits in the cold basement.
  • Idle loss – Conventional boilers often run day and night to keep hot water available – even if it isn’t needed.
  • Loss from draft regulators – Draft regulators draw in cold outside air through windows and doors, which means your boiler has to work harder to maintain temperatures.
  • Heating load mismatch – If your boiler isn’t sized for your space, it will overwork and run less efficiently than its spec suggests.
  • Insufficient maintenance – Your boiler will lose 5-10 percent or more of its performance every year without proper maintenance.

These inefficiencies – along with poor maintenance and improper installation – can really bulk up your bill. But there is a way to minimize or even eliminate these problems.

System 2000 – A different kind of boiler

Heritage features a unique boiler solution for your home – the Energy Kinetics System 2000®, which combines boiler and water heater functions to maximize efficiency in all seasons.

The unique design of the System 2000 significantly reduces or eliminates chimney, jacket, idle, and draft regulator loss, cutting your bills by hundreds of dollars every year. The System 2000 also heats water up six times faster than most water heaters.

A System 2000 boiler – sized, installed, and serviced by your HeritagEnergy technician – is an investment in your home comfort that will pay for your family for years to come.

Contact HeritagEnergy today for a FREE estimate on a System 2000 for your Hudson Valley home!

Service Plan Special
Save money every month while keeping your home comfortable and safe.
Free Propane Tank Swap
We'll swap out your old tank for a new tank at no charge to you.