The other day it was about 70 degrees warm and sunny out so I thought this would be a good time to test some solar ovens. I had three for the test. The first, a homemade one made with cardboard boxes and an old piece of glass. The inside of this one was silver in color. The second was a metal box lined with 11/2 inch Styrofoam insulation. The inside of this box was painted black and the lid was covered in aluminum foil. The third was a Global Sun Oven.
I place all three in the sun with a oven thermometer inside each. Over the next few hours I kept a record of the interior temperatures.
The test was started at 0945 hours with all three ovens about 70 degrees.
|Time||cardboard oven||Metal box oven||Global Sun Oven|
|1015 hours||150 degrees||180 degrees||240 degrees|
|1045 hours||175 degrees||220 degrees||280 degrees|
|1130 hours||180 degrees||245 degrees||325 degrees|
|1400 hours||180 degrees *||260 degrees||345 degrees|
|1500 hours||220 degrees||270 degrees||354 degrees|
|1600 hours **||205 degrees||240 degrees||290 degrees|
* I painted the inside of the cardboard oven black.
**A wind of about 10-12 miles an hour came up.
As you can see all three ovens were capable of cooking food successfully. The Global Sun Oven was the most efficient and showed the fastest temperature increase. This would be my preferred choice for cooking. The oven in the metal box functioned fairly well but took longer to heat up. More reflectors would help it.
The cardboard oven test was very interesting because it showed the dramatic change in temperature, when I painted the interior black. Prior to this the interior had been reflective silver. I am sure that adding reflectors to this oven would help.
Late in the day even though the temperature had risen to low eighties, the wind caused a drop in temperature inside the ovens.
While the Global Sun Oven is a bit pricey if you can afford it I would recommend this oven over the homemade for several reasons. It is definitely well made and I feel would outlast the others. The rapid increase in temperature at the beginning would speed up your cooking time considerably. This may be important during questionable weather. It reaches higher overall cooking temperatures.
This said, I intend to keep working to improve my homemade ovens and will post more on any new developments.