A south facing roof with unobstructed sun all year from 10am to 2pm is ideal for a solar water heater (9am – 1pm or 11am – 3pm works great too). If the collectors don’t receive 4 hours of sunlight production will go down a bit. Collectors oriented due east or west only lose about 15% of their productivity however. Output levels are predictable and this is something that SolarWerks can tell you before you make the investment in a system.
Another consideration is that solar panels for home don’t need to go on a roof. In many areas, mounting panels to a pole can improve production levels as well as meet aesthetic goals. Most homes are excellent candidates for solar if you consider all your options.