Question

Would it be better to replace an old roof with solar tiles or install panels?

Asked by Marjorie Wax
Catonsville, MD

We have a cabin with traditional roof tiles that are 15 years old, and will soon be in need of an update

Answer

Marjorie,

A few items should be considered when comparing solar shingles to panels.

Watts. Number of watts per shingle or panel, the total calculated wattage demand to operate your cottage, and total square footage of Southern facing roof required to meet the wattage demand.

Ease of maintenance. Some solar shingle products clip together to create a continuous solar array, whereas a solar panel array is daisy chained together with wires.

  • A question to ask the manufacturer or solar consultant, if one of the solar shingles malfunctions, will this shut down the complete array?
  • Also you will have to remove and test each solar shingle to determine which one has malfunctioned. To do this, you have to remove all of the preceeding solar shingles to access the faulty solar shingle and exposing your home to the elements since they are also the roofing system. The repair would increased operation cost and shorten the return on investment.
  • As for solar panels, micro inverters can be installed at each panel eliminating the shut down of the complete solar array if one of the panels malfunctions. With this type of inverter you can monitor on line the performance of each panel and determine which panel has failed, allowing you to service just the one panel with minimal effort and disruption to the roofing system which protects your home from the elements.

Warranty. Most of the panel manufacturers supply a 25 year warranty. Is this the same for shingles?

Efficiency. Do the solar shingles operate at the same efficiency as the solar panels? Some solar panels are in the 20-22% range for efficiency. There is a new panel manufacturer, not yet on the market, claiming to have 33.9% efficiency.

Consult with more than one solar panel/shingle supplier and installer and compare their comments and recommendations prior to making your decision.

 

For more information:

Read "Do you recommend solar shingles? Is the technology advanced enough for durability and problem-free installation?" a Q&A answered by Randy Potter.

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