Next we will determine the heating and cooling degree days for a typical year. These values help is find the amount of energy that will need to be supplied to the house over the entire year. First we will look at the cooling degree days (CDD). We will reference the Iowa Environmental Mesonet [40] to get averages from 1951 until 2011. The average number of CDD is about 1045 and cooling days typically are needed between the months of April and September. Heating degree days (HDD) are taken into consideration for all months except for June thru August. The average for HDD is taken to be about 6140 for a typical year.
