I like using TRNSYS for projects that include daylighting and natural ventilation. TRNSYS gets cumbersome if you have a lot of zones.

TRNSYS can directly pass natural ventilation information to and from CONTAM, which will give you fairly accurate results. This level of rigor is required for compliance with the LEED natural ventilation pilot credit if you are going for that.

Also its fairly easy to import daylighting results from Daysim or Radiance into the lighting schedules in TRNSYS.

I don't believe TRNSYS will directly do any LCA calculations. At least I have never tried.

eQuest can do daylighting and natural ventilation, but it is not as accurate as using programs that specialize in these types of simulations. Also, I have never tried doing natural ventilation in eQuest for LEED without some support from a separate bulk air flow model for CFD analysis to support the results. I don't know how they will review the model without a supporting analysis outside eQuest.

FRED BETZ? PhD., LEED AP