I wouldn't put them on the roof. Your roof has to be in good shape and shingles updated. Also who is going to take care of the maintenance for your solar panels? If the company goes under who is maintaining your solar panels? And finally, are you willing to remove the solar panels if asked to, when you are selling your house? Some people don't want them on the roof. Just a few things to keep in mind. One more, you have to have all necessary CO's (Permits) to install solar energy.