### Example 1

**Calculate the HDD for one day when the average outside temperature is 13º F.**

**Calculate the HDD for one day when the average outside temperature is 2º C.**

### Example 2

**Given the following data, calculate the HDD for the week:**

Day | Average Temperature |
---|---|

Sunday | 49° F |

Monday | 47° F |

Tuesday | 51° F |

Wednesday | 60° F |

Thursday | 65° F |

Friday | 67° F |

Saturday | 58° F |

#### Heating Degree Day

For this problem, we need to calculate HDD for one full week. The data that is given is each day, what is the outside temperature -- average outside temperature. For example, Sunday, the average outside temperature is 49 degrees F. Monday 47 degrees Fahrenheit, Tuesday it’s 51 and Wednesday it is 60 degrees F and on Thursday it is 65, Friday, 67 and on Saturday it is 58.

Day | Temperature (°F) |
---|---|

Sunday | 49 |

Monday | 47 |

Tuesday | 51 |

Wednesday | 60 |

Thursday | 65 |

Friday | 67 |

Saturday | 58 |

So we need to calculate heating degree days (HDD) for each day. One day, that is Sunday, the outside temperature is 65 minus 49 the outside temperature will give you the degree days. Similarly, 65 minus 47° Fahrenheit, one day times 65 minus 51 in this case. One day times 65 minus 60 and one day 65 minus 65. This would be zero. One day 65 minus 67. Remember when it exceeds 65, the heating degree days would be zero. In this case, also it is zero. One day on Saturday it is 65 minus 58.

Day | Temperature (°F) | Calculate HDD |
---|---|---|

Sunday | 49 | 1 day (65-49) |

Monday | 47 | 1 day (65-47) |

Tuesday | 51 | 1 day (65-51) |

Wednesday | 60 | 1 day (65-60) |

Thursday | 65 | 1 day (65-65)=0 |

Friday | 67 | 1 day (65-67)=0 |

Saturday | 58 | 1 day (65-58) |

This case it is 7.

Day | Temperature (°F) | Calculate HDD |
---|---|---|

Sunday | 49 | 1 day (65-49)=16 |

Monday | 47 | 1 day (65-47)=18 |

Tuesday | 51 | 1 day (65-51)=14 |

Wednesday | 60 | 1 day (65-60)=5 |

Thursday | 65 | 1 day (65-65)=0 |

Friday | 67 | 1 day (65-67)=0 |

Saturday | 58 | 1 day (65-58)=7 |

These two are zeros, this is 5 and this is 14 and this happens to be 18 and here it is 16. So the total sum is for one full week is 60 degree days.

Day | Temperature (°F) | Calculate HDD |
---|---|---|

Sunday | 49 | 1 day (65-49)=16 |

Monday | 47 | 1 day (65-47)=18 |

Tuesday | 51 | 1 day (65-51)=14 |

Wednesday | 60 | 1 day (65-60)=5 |

Thursday | 65 | 1 day (65-65)=0 |

Friday | 67 | 1 day (65-67)=0 |

Saturday | 58 | 1 day (65-58)=7 |

Total |
60 Degrees |

This is equal to 60 degree days.