NATE Air Conditioning and Heat Pumps Practice Exam

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Complete your NATE Air Conditioning and Heat Pumps Test. Get ready with flashcards and multiple choice questions, all with detailed hints and explanations. Achieve success on your exam!

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What is the output of a residential electric furnace when the voltage impressed is equal to 235 V and its current draw is 40 A?

10,150 Btuh
29,530 Btuh
32,080 Btuh
42,300 Btuh

The correct answer is: 32,080 Btuh

To determine the output of a residential electric furnace, you can use the formula for electrical power, which is given by P = V × I, where P is the power in watts, V is the voltage in volts, and I is the current in amperes. In this case, with a voltage of 235 V and a current draw of 40 A, you would calculate the power as follows: P = 235 V × 40 A = 9,400 W. To convert watts to British thermal units per hour (Btuh), you can use the conversion factor that 1 watt is approximately equal to 3.412 Btuh. Therefore, you multiply the power in watts by this conversion factor: 9,400 W × 3.412 Btuh/W = 32,080 Btuh. Thus, the correct output of the electric furnace at 235 V and 40 A is 32,080 Btuh, which corresponds to the answer choice. This calculation shows how to derive the thermal output of an electric furnace based on its electrical input, making it essential knowledge for understanding the performance of heating systems.