# Compare your Electric Bills to the last 5 years of DFW Weather

What are degree days?

Heating engineers who wanted a way to relate each day’s temperatures to the demand for fuel to heat buildings developed the concept of heating degree days.

To calculate the heating degree days for a particular day, find the day’s average temperature by adding the day’s high and low temperatures and dividing by two. If the number is above 65, there are no heating degree days that day. If the number is less than 65, subtract it from 65 to find the number of heating degree days.

For example, if the day’s high temperature is 60 and the low is 40, the average temperature is 50 degrees. 65 minus 50 is 15 heating degree days.

Cooling degree days are also based on the day’s average minus 65. They relate the day’s temperature to the energy demands of air conditioning. For example, if the day’s high is 90 and the day’s low is 70, the day’s average is 80. 80 minus 65 is 15 cooling degree days.

Heating and cooling degree days can be used to relate how much more or less you might spend on heating or air conditioning if you move from one part of the country to another. Of course you’d have to take into account how well insulated your new home will be in comparison to your old one and the different costs of electricity, gas or heating oil. You could also use records of past heating degree days to see if the money you’ve spent on insulation, or a newer furnace or air conditioner is paying off. To do this, you’d also need records of past energy use.

DALLAS LOVE FIELD HEATING DEGREE DAYS   ( HDD )

WINTER                November          December           January              February              Four Month Total

2009 / 2010             161                      665                    613                        623                        2,062

2008 / 2009             225                      539                    528                        259                        1,551

2007 / 2008             205                     498                     593                        341                        1,637

2006 / 2007            224                      446                    683                         424                        1,777

2005 / 2006            184                     506                     281                         412                        1,383

FORT WORTH MEACHAM HEATING DEGREE DAYS   ( HDD )

WINTER                November          December           January              February              Four Month Total

2009 / 2010             195                      710                    656                        629                        2,190

2008 / 2009             260                      577                    559                        288                        1,684

2007 / 2008             240                     560                     636                        388                        1,824

2006 / 2007            253                      477                    720                         453                        1,903

2005 / 2006            203                     534                     308                         444                        1,489

ARLINGTON HEATING DEGREE DAYS   ( HDD )

WINTER                November          December           January              February              Four Month Total

2009 / 2010             170                      594                    566                        620                        1,950

2008 / 2009             253                      542                    540                        259                        1,594

2007 / 2008             217                     523                     615                        364                        1,719

2006 / 2007            235                      461                    689                         429                        1,814

2005 / 2006            206                     521                     299                         425                        1,451

McKINNEY HEATING DEGREE DAYS   ( HDD )

WINTER                November          December           January              February              Four Month Total

2009 / 2010             225                      750                    702                        697                        2,374

2008 / 2009             318                      627                    636                        348                        1,929

2007 / 2008             258                     588                     707                        449                        2,002

2006 / 2007            316                      546                    758                         510                        2,130

2005 / 2006            252                     622                     399                         502                        1,775

DENTON HEATING DEGREE DAYS  ( HDD )

WINTER                November          December           January             February              Four Month Total

2009 / 2010             231                      755                    645                        697                        2,328

2008 / 2009             305                      635                    643                        322                        1,905

2007 / 2008             233                     588                     689                        422                        1,932

2006 / 2007            289                      486                    746                         490                        2,011

2005 / 2006            252                     595                     383                         490                        1,720

If you wish to calculate your Heating Degree Days ( HDD ) so they match exactly to your Electric Billing Cycle, Click This Link and it will take you to the local National Weather Service’s  climate data.  Follow these 4 simple steps after clicking the link.      http://www.weather.gov/climate/index.php?wfo=fwd

1. Product »  Select  Preliminary Monthly Climate Data

2. Location »  Select  The location nearest your home

3. Timeframe »  Select  Archived Data:

4. View »   Select   The month and click Go!