Roman Jaques recommends that all teams use a thermal modeling tool like BRANZ's Annual Loss Factor tool, ALF. It will help calculate the effects of insulation, double glazing, window sizing and placement, and varying house size on annual energy consumption and costs. See http://alf.branz.co.nz/
Dave Strachan, a SHAC 09 Judge, recommends that all teams get design advice early on in their design, to help refine ideas before it is too hard to change. Solicit several design students or professionals for their input. Call Tim at 0800 SHAC 09 for a local referral.