The letter “D” has a lot in store for us. If this feels like Sesame Street, I apologize, we just think it is important to dot all our i’s and cross all our t’s as we cover the vastness of window manufacturing knowledge. To share and dispense this knowledge in an orderly and thorough fashion, we decided to move chronologically through the alphabet. We’ve been at it for quite some time now, and we are only now arriving at the fourth letter of the alphabet. Now, granted, we did some jumping around before we formally decided to apply order to the madness… but we haven’t looked back yet. So, getting on with our discussion of window manufacturing terms, we’ll unveil our next term.

Degree day is our term for the day, and what a term it is. The more formal definition for this term is a unit of measure that represents a deviation of the mean, daily outside temperature from a fixed reference point, by a measure of one degree. More often than not, 65 degrees Fahrenheit is the standard reference point used when determining this measure. So, you might be wondering why this has any relevance to the window manufacturing industry or the vinyl window replacement industry. Well wonder no more. The bottom line in all of our discussions and explorations of aluminum window and vinyl window terms is that it all boils down to energy efficiency and protection from the elements. A degree day has a significant role to play in the measure of this kind of efficiency. To truly understand the capabilities and limitations of a given piece of fenestration, it is critical to know the real world performance data. The measure of the degree day is one more tool to help understand and measure the efficiency of a given product.