U Values and SHGC values for replacement windows

[jbpring]

Good afternoon. I am looking for any info at all on the windows that were replaced in a home I purchased 2 years ago. The back door was replaced with a Legance 3 Patio Door Type:DDSG Code: TRI - K - 36.

As far at the other windows in the house I can not find any marking indicating what manufacturer they are all I know is that they were installed back in 2015. My only other thought would be to look up what the energy code standards for windows were in 2015 in North Carolina and use that as my starting point.

I am trying to do a Load calculation on the house because I am near to needing to replace my central HVAC unit and I do not believe that the company that replaced the HVAC in 2015 after the windows were replaced ever did a load calc for my house. When I turn my heat on the unit only runs for 2 minutes maybe a little longer then satisfies the T stat. In cooling mode the unit and maintain 70 degrees all summer long which is fine but we have to keep the thermostat set to 70 or lower because if it is not it will not run long enough to take a considerable amount moisture resulting in the house feeling sticky. My best guess is the unit is oversized.

If I can get the true rating for these windows I should be able to appropriately size the unit but for now I'm just guessing. Does anyone know how to go about finding this information?

Thank you in advance!

[HomeSealed]

The Legance was made by Thermal/Thermal Industries which is out of business. I'd expect a u value on your windows and sliding door(s) to be something around .28-30 for your area in 2015, assuming that they are double pane and not. triple pane.

[jbpring]

Thank you. I was thinking it was around that. I did not realize that they are no longer in business thats good to know and explains why I couldn't find hardly any info online.

Do you know what the typical SHGC on their windows are?