Hi everyone!

90.1-2007 Table 6.8.1F for boilers prescribes a minimum combustion efficiency (EC) of 82% for gas boilers larger than 2.5MBtu/h. This is the burner's efficiency before flue losses.

The same boiler's thermal efficiency, inclusive of flue losses, would be a lesser figure.

When modeling such boilers for an Appendix G baseline, what is actually appropriate to enter for the boiler's HIR input? As I understand it, this HIR input in eQuest is the inverse of thermal efficiency (net input vs. net output), and would be inclusive of flue losses.

This is for a LEED project, so I'd like to cite something solid to demonstrate what thermal efficiency is appropriate to assume for a baseline boiler of this size. Has anyone gone down this path before?

Thanks!

~Nick
[cid:489575314 at 22072009-0ABB]

NICK CATON, P.E.