Many are. Solar panels and photovoltaic wire are carefully engineered to work in all climates. Not all residential roofs are the perfect fit for solar panels (for example, if a roof is too old, too small, or too sloped, or there is too much shade from a nearby tree canopy), so rooftop panels may not always be the best option. In most cases, south-facing roofs with a slope between 15 and 40 degrees perform best, but there are exceptions to every rule, and community solar energy systems may be a better fit for some situations.