Gas Heat ESCO Practice Exam

Typical condensing furnaces have an AFUE rating of at least:

1. 80%

2. 85%

3. 90%

4. 95%

The correct answer is: 80%

Condensing furnaces are designed to be highly efficient by extracting additional heat from the combustion exhaust gases that would otherwise be wasted in a non-condensing furnace. Typically, these furnaces have an AFUE (Annual Fuel Utilization Efficiency) rating of at least 90%. This means that at least 90% of the fuel being consumed is being converted into usable heat for the home. Therefore, an AFUE rating of 80% (choice A) is actually lower than what is considered typical for condensing furnaces, making it the correct answer in this case.