Quick Answer: Solar PV and solar thermal both harness energy from the sun but for different purposes. Photovoltaic (PV) systems convert sunlight directly into electricity, while thermal systems produce thermal energy for residential heating systems such as hot water or space heaters. The differences also come down to how. Solar photovoltaic (PV) technology is a renewable energy system that converts sunlight into electricity via solar panels. A PV panel contains photovoltaic cells, also called solar cells, which convert light photons (light) into voltage. Solar thermal panels perform a similar function to PV panels by converting sunlight into usable energy. However, thermal panels differ in. Solar PV and solar thermal both utilise renewable energy. PV systems harness sunlight to generate electricity to use throughout your home, while solar thermal systems use sunlight to heat water or residential spaces. Either.