A 'solar heating panel' in most cases is a water tank exposed to the sun as much as possible painted in black. Or maybe put inside a black box. Not a lot of electricity work there.
You usually want a water tank to buffer the thing, so you can get hot water at night. Temperature will be all over the place without that. Giant hot water tanks in attics need extra structural support, which was a problem in Florida at one time.
There are some fancier setups that will work in cold weather. Some systems use antifreeze in the panels, and a heat exchanger.
[1] http://www.alternative-energy-tutorials.com/solar-hot-water/...