Yes, there is a program by Slant/fin called Hydronic Express.
Do Google search and you will find it. Its free although no longer supported. There is s new version for the Iphone and Ipad. The laptop version I like better however. I have been told that it is a bit pessimistic on actual BTU loss. It errs on the high side.
Slant/Fin "Heat Loss Explorer isn't pessimistic about infiltration where high winds are concerned.
Pessimism on heat/cool occurs in heat loss programs comes when you either round UP or round DOWN. I have always rounded UP.
There is also HVAC-Calc v4. Not free but quite easy to use and I like its "systematic" approach in organizing and collecting the data.
I bought only the "residential customer" license, which is cheap but it lasts for 1-2 months only. But it's suited for 1-time type of job I guess.
This post was edited by an admin on March 24, 2013 7:28 PM.