Gas Heat ESCO Practice Exam

Which of the following is a typical AFUE rating for a condensing furnace?

1. 70%

2. 80%

3. 90%

4. 95%

The correct answer is: 70%

The typical AFUE (Annual Fuel Utilization Efficiency) rating for a condensing furnace is generally higher than 80%. Condensing furnaces are designed to achieve high efficiency by utilizing the heat from flue gases that would otherwise be lost in conventional systems. A rating of 90% or greater is common for these types of furnaces, with many high-efficiency models reaching 95% or higher. Therefore, the correct choice reflects that modern condensing furnaces operate efficiently, capturing more of the heat generated during combustion. The rating of 70% would typically align more with older, less efficient heating systems. Ratings of 80% and 90% might represent standard efficiencies for non-condensing furnaces or older condensing models but do not capture the full efficiency potential of advanced condensing technology.