# AC vs Fan: Energy Consumption

##### Subject

Building Services

,Climatology

,##### Academic Year

2'nd Year

,##### Complexity Level

Intermediate

,##### Content tags

Air Conditioning

,Climate Justice

,Energy Consumption

,##### Activity Type

Field Measurements

,##### Activity duration

1-2 hours

,##### Objective

To compare the energy consumption of a fan vs a room air conditioner.

##### Outcome

Students will realize that an air conditioner consumes much more energy than a ceiling fan.

##### Requirements

An air conditioned laboratory (in college building), power meter.

##### Prerequisites

- Conceptual knowledge of electrical energy consumption.
- Knowledge of how a power meter works.
- Suitable for final year architecture students.

##### Procedure

- Identify a laboratory (eg: a computer lab) in your college having an air conditioner in it.
- Insert air conditioner plug into the power meter.
- Insert the power meter into electrical socket
- Switch on the AC.
- Note the power consumption from the power meter.
- Keep noting the power consumption after every 10 minutes for 1 hour. Tabulate them as shown below.
- Estimate the mean power consumption by taking an average of all the intermittent values of power consumption.
- Estimate the energy consumption for 1 hour.
- Identify a fan in the classroom.
- Look for the nameplate on the fan which states itâ€™s power consumption.
- Estimate the hourly energy consumption of the fan.
- Compare the hourly energy consumption of the fan vs AC.
- Estimate the no. of fans which collectively consume energy equivalent to one air conditioner.

##### Calculations

- Table for calculating energy consumption of an AC.

Time Interval | Power Consumption (kW) |

Initial Time (A) | |

10 minutes (B) | |

20 minutes (C) | |

30 minutes (D) | |

40 minutes (E) | |

50 minutes (F) | |

60 minutes (G) | |

Average $$\frac{A+B+C+D+E+F+G}{7}$$ (P_{AC}) |

*Table for calculating energy consumption of an AC*

**Step 2:** Energy Consumption of AC (kWh) = Average Power Consumption (kW) x no. of hours used (hrs) = P_{AC} (kW) x 1 (hour)

**Step 3:** Energy Consumption of Fan (kWh) = Power Consumption x no. of hours used (hrs.) = P_{FAN} (kW) x 1 (hour)

**Step 4:** No. of fans which collectively have the same energy consumption as that of an AC = $$\frac{\:\text{Energy consumption of an AC (kWh) }}{\:\text{Energy consumption of a fan (kWh)}}$$