A solar array will last at least 25 years. It’s important that the roof underneath it be in good shape. If your roof is more than 10 years old, you should have it evaluated to determine its remaining lifespan. You may want to consider repairs or replacement before installing solar. NOTE: According to an FAQ on the IRS website, in most circumstances roof improvement or replacement costs can not be included in the basis for the federal tax credit. Solar shingles/tiles may qualify. We recommend reading carefully through the IRS FAQ and through the applicable tax form (IRS Form 5695) for more information.