At least here in California, having solar panels on a non south facing roof usually only reduces production by 10-20%, as long as it's not entirely north facing. Solar systems are often slightly undersized - it's more cost effective to size it so it handles average load rather than the summer peaks you only see for a few weeks per year - so the actual difference for a given system may be less.

With my system, I see the best output from south-east facing panels since they get the morning sun. West facing panels are also fairly popular here due to time-of-use electricity plans. Some electricity plans have peak pricing from 4 to 9 pm, so people want to try and collect as much sunlight as possible during that period before sunset.