What is the efficiency of my installed condensing boiler or water heater?

Norm Hall
June 15, 2009
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If you answered 97%, you’re not alone. You’re most likely not right, but you’re not alone. Many boiler manufacturers have jumped into the world of condensing boilers, and they brought along their best marketing tools to help differentiate them from the competition. Here’s a quick example of what it takes to achieve 97% efficiency:


Using the above efficiency chart for the Aerco BMK1.5LN Benchmark Boiler, one can see that a typical 180°F – 160°F system will not get you to that level of efficiency. In fact, the system requires a 80°F return water temperature AND the burner will have to be modulated down to 5% in order to achieve the highest efficiency.

This series of Monday Morning Minutes will go into great detail about condensing boilers/water heaters. Here are the topics that we will discuss:
• Selection Considerations
• Matching Boilers/Water Heaters to Systems
• Controls

In the next few issues, we will begin our discussions with selection considerations including materials of construction, turndown ratios, condensation handling and venting.

Thank you for using products sold by R. L. Deppmann Company in Michigan and Ohio!

Disclaimer: R. L. Deppmann and it’s affiliates can not be held liable for issues caused by use of the information on this page. While the information comes from many years of experience and can be a valuable tool, it may not take into account special circumstances in your system and we therefore can not take responsibility for actions that result from this information. Please feel free to contact us if you do have any questions.

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