You guys have been so helpful about other aspects of planning our retirement home in NC that I thought I'd come back for more help. We are having a double-sided gas fireplace installed between the great room & the screened-in porch. We have to approve the final plans so they can submit the permitting request so I need some info ASAP. This house is an energy efficient, Energy Star certified house with a HERS index of 74. Can anyone provide any insight on what having a double-sided fireplace will mean to our energy efficiency? My husband suddenly has concerns that he'll be wasting gas since both sides provide heat at the same time (don't they?). Thanks in advance.