Passive house and sunshine hours
is there a ballpark rule of thumb that spans different regions for the mean monthly sunshine or possible percent sunshine that is conducive to a favourable result in PHPP?
GBA Detail Library
A collection of one thousand construction details organized by climate and house part
Perhaps you are confusing passive solar design principles with the Passivhaus standard. The Passivhaus standard (the standard underlying the PHPP software) can be applied to any building, regardless of the amount of insolation (hours of sunlight) at the building site.
Of course, buildings in very sunny climates will require a different design from buildings in cloudy climate. But all you have to do is to adjust the design of the building -- its shape, the size and glazing specification of the windows, and the insulation R-values, among other factors -- and you can meet the Passivhaus standard using PHPP in a wide variety of climates.
Of course, in some climates it isn't very cost-effective to meet the Passivhaus standard. But that's another issue altogether.
Solar radiation by location: