HDD, what is that? Hot Diggity Dog? Hard Disk Drive? Well, those are definitions of that acronym along with a couple dozen more but this post refers to Heating Degree Days. Heating Degree Days is a measurement that is generated from the outdoor air temperature throughout the year for a given location. Annual figures vary from approximately 20,000 in Alaska to 500 in Florida and even near 100 in Hawaii. So by those figures, you can safely assume a warmer climate is going to have a lower HDD. Morris County NJ the HDD value falls in around 6,039 according to the ResCheck software. This is the software architects use to make sure your house or addition conforms with the most current energy code and guides them as to how much insulation to provide in your floors, ceilings and walls after inputting exterior surface areas, ceiling areas, floor areas along with windows and doors. According to the US Department of Energy Heating Degree Day is calculated as follows: A unit, based upon temperature difference and time, used in estimating fuel consumption and specifying the nominal heating load of a building in winter. For any one day, when the mean temperature is less than 65 degrees there exists as many degree days as there is Fahrenheit degrees difference in temperature between the mean temperature for the day and 65 degrees. So with that in mind you can understand how Florida’s calculation is so low! Not too many days below 65 degrees and not that much need for heat. In the past 20 years, the average heating degrees days have decreased but I have got to believe after this recent cold spell that calculation has changed! If you take a look at the National Weather Service you will see that in the past week alone Newark, NJ was 147 HDD which is 14% higher than last year’s norm. Brrrrrrrr!