Solar roof vs solar panels: the return on investment

Compare the whole job, not the sticker

On an average 2,588 square foot roof, a solar roof averages $66,615 and covers the roofing too. Panels average $20,989, but if the roof underneath is due for replacement you also need about $16,261 of asphalt under them. That is the comparison that matters.

Where each one wins

• Roof already due for replacement and appearance matters: solar roof.
• Roof with ten or more years of life left: panels, every time.
• Maximum generation per square foot of available surface: panels.
• Heavily shaded or complex roof with few clean planes: panels on the best plane only.
• Historic district or strict aesthetic rules: solar roof.

How payback actually works out

Payback is the net installed cost after incentives divided by your annual energy saving. Panels usually reach payback sooner because they cost less per watt. A solar roof stretches the payback but replaces a capital expense you were going to make anyway, so the honest comparison subtracts the cost of the roof you would have bought.

Things that quietly change the maths

• Local electricity rate and how fast it is rising.
• Net metering rules where you live, which decide what exported power is worth.
• Federal, state and utility incentives, and whether you can use the tax credit.
• Roof pitch and orientation: south facing planes at moderate pitch produce most.
• Whether you own the system outright or lease it.

A practical way to decide

• Measure the roof and get the real surface area, not an estimate from the floor plan.
• Price a straight replacement in your chosen material.
• Price panels on top of that, and a solar roof as a single job.
• Divide each net cost by your annual saving and compare the years.