Can you tell me how to calculate the “R-Value” of glass based on its “U-Value”? I have an issue with a building inspector in my town based on energy codes, and my wall area must achieve a certain overall “R-Value” for me to get a certificate of occupancy permit. I have “R-Values” for everything but the glass. The glass company that put the glass in can only tell me the “U-Value” which they said is 0.29. According to the label on the glass when it was installed, the glass is an insulated unit of Solarban 60 with Low-E. Does any of this make sense to you, and if so, how do I get an “R-Value” for this glass?
This whole “U-Value” vs. “R-Value” thing can be a little confusing. For many years now, most of the glass manufacturers have provided “U-Values” only. However, the conversion, or glass “R-Value” calculator if you will, is pretty simple. You see, “U-Values” and “R-Values” are the reciprocals of each other. Remember those old high school math classes? We were taught that to get any number’s reciprocal, you simply divide 1 by that number. So the reciprocal of your glass unit’s “U-Value of 0.29 can be determined by dividing the number 1 by 0.29 which would give us 3.4482 or roughly 3.5 and that would be the “R-Value” for your glass. If you had a product’s “R-Value” and wanted to know its “U-Value” the process would get reversed … divide the number 1 by its “R-Value” and you would have its “U-Value.” I really hope this helps and thank you for reaching out!
-Glass DetectiveRead More
© 2019 Glass.com Inc. All Rights Reserved. No reproduction without expressed written permission. Questions? Contact email@example.com.
The Glass Detective attempts to answer all questions accurately but cannot be held liable for any information provided or omitted. You should always work with a licensed, insured and reputable glass shop that can assess your specific needs and local building codes and offer professional services. Never attempt to cut, install, or otherwise work with glass yourself. The Glass Detective answers questions on an informational basis only.