Not checking with local authorities. You have up to three sets of people you need to get approval from if you live in a city, suburb or especially a historical district (folks in rural areas usually have little to worry about here). Check with your local zoning board. There may be restrictions on what you can do to the exterior of your house, especially if your southern exposure faces the street. Sometimes it is as simple as applying for a zoning variance. It may take a few weeks to get approval but cover your behind! One pesky neighbor could bring your solar dreams to a halt. The building inspector needs to be sure you are not putting your roof in jeopardy. Solar panel are heavy and roofs are not designed, generally, to carry loads. You may need to reinforce the area over which you are planning to install the panels. Most newer homes, however, shouldn’t need altering. If you belong to a homeowner’s association make double sure you have the latest bylaws in hand. Make sure you don’t need approval by the association to install panels. I would even suggest having a lawyer look over the regulations before you start if you have any questions about it. A couple hours of a lawyer’s fees is cheaper than dismantling a solar array.
All or nothing, full speed ahead. Solar systems are modular. One panel connects to another and another until you run out of panels and then on to the inverter. If you do your planning right, you can install what you can afford now and come back to install more later. My dad always said, “If you’re buying something that you intend to keep for more than five years, buy the highest quality you can afford.” His advice plays well here. Fewer higher efficiency panels now can be added to next season. But if you cover your entire roof with lower efficiency, cheaper panels now, you have no place to expand later. If you’ve done the math, you know how many kilowatts you can get out of solar arrays of different efficiencies. The more efficient the panel, the more energy you can create in a given space. A roof filled with high efficiency panels might take two or three years to afford but they may provide a profit over a full roof of low efficiency panels that don’t quite generate enough power.
Not checking with your uncle. Even though your local authorities might put a roadblock or two in your way (see Mistake No. 1), your state and federal government has plans in place to help you ‘go solar.’ At the time of writing, there are federal tax credits available to homeowners who install solar panels. They may increase or go away but it is in your best interest to find out if there is money on the table. Many state governments have plans to reimburse homeowners up to 70% of the cost of installing solar panels. Your mileage may vary depending on where you live. But you should check them out. Many of these plans have proven so popular that there are many people on waiting lists while the state gets more dollars to fund the programs.