I would second some of the suggestions, but putting heat in the floor might be expensive, since floor-to-floor is limited...requiring demo at original floor/structure? Perhaps an offset to energy usage, as in providing solar panels at the roof, will help offset and provide a better source for heating and cooling.
I have a question: As for the fresh air issue, if you are able to utilize a more comprehensive zoning strategy for climate areas in building, does that help with using operable windows. Additionally, will this satisfy the fresh air requirements?
Systems type could also affect energy star rating. What about displaced heating/ventilating, providing same at floor level (through partitions) instead of at ceiling? What does your engineer say? I agree, if you don't have one at beginning of design, you could be missing opportunities for savings as well as energy achievements.
Good luck!
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Mary Austern AIA
Georgetown CA
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