While solar utility solutions are becoming more common, I'd be very suspicious of such dramatic claims.
There are way too many variables to back up a blanket promise like the one stating you'll save more than 75 percent on electricity. Every home has solar potential based on where roof faces, where trees are located, and many other details - but it varies from home to home. Even more, building your own solar panels is no way to start a DIY career!
Dig into the history of this company, and of course their references. In today's world, your reputation is searchable online. If the company has the level of success they claim, it should be verifiable, and easy to find online. However, allow me to remind you of the old adage: If it sounds too good to be true, there's a good chance it is!
And whether or not you end up having solar panels installed, remember that there are plenty of smaller steps you can take toward a greener, more efficient home.