Carefully consider the types of solar panels you plan on having installed. Long ago, if you didn't have enough roof space, you'd need very expensive high efficiency mono-crystalline panels. There are now more advanced polycrystalline panels and even thin film panels. If you've got enough roof space, you might wish to look at the size of the panels in relation to their output capacity to avoid having insufficient panels that you need more of later.
You might be able to get your solar energy equipment installed for a huge discount or perhaps even free. The government is trying to promote solar energy benefits and many wish to cover apart or all of the costs in return for its installation.