I am simulating a mixed-use building for LEED certification which uses
solar thermal panels for radiant in-floor heating. There is a gas fired
back up, but I'm curious as to whether I should use System 1 with gas
heat or System 2 with electric heat from ASHRAE 90.1-2004 Appendix G
Table G3.1.1A for the baseline model. System 2 is required when heating
type is "Electric and Other," Other indicitive of Solar, but should I
select my baseline system based on the back up fuel?

Thoughts and experience is much appreciated.

--
Matthew Higgins, LEED AP