Photovoltaic systems need to be able to receive direct sunlight for most of the day. Climate is not an important issue because PV systems are not so affected by bad weather. In fact, some PV modules work better in colder weather. Almost everywhere in the world there is enough sunlight for solar power systems to work effectively. Most homes have enough roof space to install PV systems, and they can be integrated into walls or covered with panels on porches and backyard patios.