Part 1
Backyard Roof Test
Summary
| Max Temp (℉) | Average Temp Difference* (℉) | Median Temp Difference (℉) | Max Temp Difference (℉) |
Galvalume w/ Air Gap | 113.4 | 3.94 | 0.42 | 16.27 |
Galvalume w/ Insulation | 116.47 | 4.27 | 0.30 | 18.34 |
SolarBoard OSB | 124.78 | 3.68 | 0.25 | 12.93 |
Solar Shingles | 119.76 | 3.09 | 0.17 | 12.84 |
*The temperature difference is compared to the control (traditional comp roof) during the same time period.
High numbers are better.
Sensor
Each test structure has a wireless temperature/ humidity sensor suspended in more or less the middle.
Control Variable: Typical Asphalt Shingle Roof
Data Collected from May 19th - June 9th
Galvalume w/ Air Gap vs Asphalt Shingles
Galvalume Roof Panel with a ¾” Air Gap
Average Temp | 87.5 | 91.4 |
Median Temp | 83.9 | 84.9 |
Max Temp | 113.4 | 126.3 |
Average Δ Temp | 3.95 |
Median Δ Temp | .42 |
Max Δ Temp | 16.27 |
* Positive numbers mean the Comp roof was warmer
Delta T = Temp Comp - Temp Galvalume
Temperature difference for previous graph
Average Temp | 88.6 | 92.5 |
Median Temp | 85.5 | 87.4 |
Max Temp | 113.4 | 125.8 |
* Positive numbers mean the Comp roof was warmer
Delta T = Temp Comp - Temp Galvalume
Average Δ Temp | 3.9 |
Median Δ Temp | 0.6 |
Max Δ Temp | 15.9 |
Temperature difference for previous graph
Average Temp | 88.6 | 92.5 |
Median Temp | 85.5 | 87.4 |
Max Temp | 113.4 | 125.8 |
*** It’s possible that the temp rise after ~ 4PM is partly because the unshade 3rd wall (facing NW) gets hit with late afternoon sun ***
Data Collected from June 13th - July 17th
Galvalume w/ Air Gap and 1” Foam Insulation vs Asphalt Shingles
Galvalume Roof with a ¾” Air Gap & 1” Foam Insulation
Average Temp | 88.01 | 92.28 |
Median Temp | 84.51 | 84.93 |
Max Temp | 116.47 | 130.39 |
Temperature difference for previous graph
* Positive numbers mean the Comp roof was warmer
Delta T = Temp Comp - Temp Galvalume
Average Δ Temp | 4.27 |
Median Δ Temp | 0.30 |
Max Δ Temp | 18.34 |
Average Temp | 90.32 | 94.49 |
Median Temp | 85.39 | 85.06 |
Max Temp | 116.47 | 130.39 |
Temperature difference for previous graph
* Positive numbers mean the Comp roof was warmer
Delta T = Temp Comp - Temp Galvalume
Average Δ Temp | 4.17 |
Median Δ Temp | -0.17 |
Max Δ Temp | 17.51 |
Data Collected from July 18th - August 2nd
Solarbord OSB vs Asphalt Shingles
Asphalt Shingle Roof with Solarbord OSB
Average Temp | 93.87 | 97.55 |
Median Temp | 89.95 | 91.04 |
Max Temp | 124.78 | 134.24 |
Average Δ Temp | 3.68 |
Median Δ Temp | 0.25 |
Max Δ Temp | 12.93 |
* Positive numbers mean the Comp roof was warmer
Delta T = Temp Comp - Temp Solar Board
Data Collected from August 4th- August 25th
Solar Shingles and Solarbord OSB vs Asphalt Shingles
Solar Asphalt Shingle Roof with Solarbord OSB
Average Temp | 91.58 | 94.67 |
Median Temp | 87.30 | 88.13 |
Max Temp | 119.76 | 130.43 |
Average Δ Temp | 3.09 |
Median Δ Temp | 0.17 |
Max Δ Temp | 12.84 |
* Positive numbers mean the Comp roof was warmer
Delta T = Temp Comp - Temp Solar Shingles
Part 2
Conditioned vs Vented Attic
The Test Setup
The following data was collected using the same Sensor Push Temp/Humidity logger.
Both single story office buildings used in this test have similar construction except for the difference in attic insulation. Both have basic asphalt shingles. One is a standard vented attic with code minimum insulation at the floor. The other has code minimum open cell spray foam under the roof sheathing.
The sensors were placed ~6’ above the attic floor.
Each attic contains 2 seperate air handlers, with standard leaky flex ducts, but no supply or return in the attic space.
“Winter… in Austin”
| Conditioned Attic | Vented Attic |
Average Temp | 69.41 | 52.52 |
Median Temp | 69.27 | 52.23 |
Max Temp | 76.18 | 87.13 |
Min Temp | 63.79 | 26.03 |
Vented Attic is warmer than Conditioned Attic
Vented Attic is Cooler than Conditioned Attic
| Difference (℉) |
Average | -16.89 |
Median | -17.37 |
Max | 11.14 |
Min | -38.92 |
| Conditioned Attic | Vented Attic |
Average Dew Point ℉ | 43.80 | 37.59 |
Median Dew Point ℉ | 43.48 | 36.74 |
Max Dew Point ℉ | 55.78 | 65.71 |
Min Dew Point ℉ | 35.40 | 13.63 |
Average RH | 39.93 % | 58.15 % |
Median RH | 39.47 % | 58.88 % |
Max RH | 50.03 % | 85.67 % |
Min RH | 33.61 % | 26.26 % |
Summer
| Conditioned | Vented |
Average Temp ℉ | 78.31 | 95.29 |
Median Temp ℉ | 77.88 | 90.87 |
Max Temp ℉ | 88.06 | 129.87 |
Min Temp ℉ | 74.74 | 76.07 |
Vented Attic is hotter than Conditioned Attic
| Difference (℉) |
Average | 16.98 |
Median | 12.84 |
Max | 46.26 |
Min | 0.60 |
| Conditioned Attic | Vented Attic |
Average Dew Point ℉ | 63.06 | 69.83 |
Median Dew Point ℉ | 62.64 | 69.02 |
Max Dew Point ℉ | 71.48 | 80.38 |
Min Dew Point ℉ | 58.12 | 60.82 |
Average RH | 59.14 % | 47.11 % |
Median RH | 58.54 % | 47.73 % |
Max RH | 66.02 % | 83.90 % |
Min RH | 54.64 % | 19.67 % |