GBA Logo horizontal Facebook LinkedIn Email Pinterest Twitter Instagram YouTube Icon Navigation Search Icon Main Search Icon Video Play Icon Plus Icon Minus Icon Picture icon Hamburger Icon Close Icon Sorted

Community and Q&A

Cool roofs and solar PV panels

user-721843 | Posted in Energy Efficiency and Durability on

Does anyone know of studies on the effect of PV panels on the rooftop solar heat gain calculation? I imagine there’s some shading, some absorption and emittance from the dark colored panels, and overall a small effect due to surface area, but haven’t seen any studies…

GBA Prime

Join the leading community of building science experts

Become a GBA Prime member and get instant access to the latest developments in green building, research, and reports from the field.


  1. GBA Editor
  2. user-721843 | | #2

    Thanks Martin!

  3. user-1108982 | | #3

    Here's a quantifiable result of what happens: . This chart shows the attic to outside temperature difference, on an average monthly basis.

    In 2009, prior to adding solar panels, summer time highes were at 10 - 11°F (monthly avg of difference between attic and outside temp).

    In March, 2010, 36 solar PV panels were placed on a South facing roof area (picture here: ). From the chart, it's clear to see that the summertime highs came down to 7 - 8°. In other words, the solar panels reduced the average attic to outside temp difference by about 3° in summer months.

    While the 3° improvement is clear to see, I'm uncertain how to further quantify it into actual kWh reduced for heating and cooling.

    (Carefully looking at the chart shows that this year (2012) the avg monthly attic to outside temp difference increased about 0.5°, accurately reflecting a substantial amount of blown in insulation added into the large attic in April.)

    Hope this helps.

Log in or create an account to post an answer.


Recent Questions and Replies

  • |
  • |
  • |
  • |