Which one of the Roof/Attic options do I choose?

The Roof Material Type 16 in the RHVAC (and ACCA) Tables give you a lot of options. What’s the difference? They seem the same!






In the Duct Load factor screen under the Attic Ceiling Type is a column for Summer Attic Temperature.


This provides more information about these different categories in the Duct Load Factor section.

Click on the down arrow next to Attic Ceiling Type. Note the column for Summer Attic Temperature.








These temperatures are a rule of thumb for the temperature in the attic in the summer months.

When selecting the appropriate Roof Material, you should keep these temperatures in mind. For example. in northern climates the summer temperature in the attic might be 95 or 105 where the same house in Louisiana will be 125 – 130. Therefore, for the same house, same roof, those of us in cooler climates will choose 16E or F for our roof and you guys in the hotter climates will use 16B.



Leave a Reply

Your email address will not be published. Required fields are marked *

Powered by: Wordpress