By calculating degree days, you can project your future energy use and also compare it to past months and years. It’s a relatively simple formula that uses 65 degrees Fahrenheit as a baseline.
Let’s say the high for a spring day is 65 degrees Fahrenheit, and the low is 45 degrees Fahrenheit. That means the average temperature for that day is 55 degrees Fahrenheit, or ten degrees cooler than the 65-degree baseline, making it a ten-degree heating day. If the high is 80 degrees Fahrenheit, and the low is 66 degrees Fahrenheit, it’s an eight-degree cooling day. In other words, you’re adding the high and low and then dividing by two, then comparing that resulting number against the baseline of 65.
Add up every day of the month, and you’ll get a number that correlates with the power needed to heat or cool your home for that month, excluding fluctuations in actual energy costs.
The National Weather Service can provide the information needed to compute degree days. You can also check out the National Climatic Data Center’s State of the Climate site.
Our technicians here at Overland Park Heating and Cooling also help you use degree day calculations to gauge the efficiency of a new furnace or the cost of a new room addition. Contact us at Overland Heating and Cooling to get more answers to your questions.
Our goal is to help educate our customers about energy and home comfort issues (specific to HVAC systems). For more information about degree days and other HVAC topics, download our free Home Comfort Resource guide.