Box Cookers

Box Cooker

Basic Box Cooker

Solar box cookers typically cook food at temperatures in the 100 – 175 °C (212 – 347 °F) range. Depending on their size, this type of solar cooker can accommodate multiple pots simultaneously. The sides and bottom are insulated to retain cooking heat. Worldwide, they are the most widely used. There are several hundred thousand in India alone.

A Basic Box Cooker is generally homemade (Click here for designs), with an insulated box covered with one pane of glass, with one reflector attached above to increase its solar footprint. A dark pot is set inside of the box and the glass top is locked tightly, keeping in the sun’s heat.

This design, in general, reaches higher temperatures than a Basic Panel Cooker because of its increased insulation.

Examples of these type of cookers are:

The Easy Lid Cooker, and The Minimum Solar Box Cooker

The Easy Lid Cooker

The Easy Lid cooker is a variation of the Minimum Solar Box Cooker. This design is especially easy to build since half of the larger cardboard box becomes the lid, so there is no need to build a separate lid as with the Minimum Solar Box Cooker.

Although designs for cardboard cookers have gotten simpler, fitting a lid can still be difficult and time consuming. In this version, a lid is formed automatically from the outer box.

The Minimum Solar Box Cooker

The “Minimum” Solar Box Cooker is a simple box cooker that can be built in a few hours for very little money. When this cooker was designed it was named the “Minimum Solar Box Cooker” because, at the time, it represented the simplest design that could be devised. What wasn’t communicated was that this is a full-power cooker that works very well, and is in no way minimum as far as its cooking power goes.

Advanced Box Cooker

In addition to an insulated box, Advanced Box Cookers utilize a more sophisticated reflector system that can better absorb off-angle sunlight. Interior racking for the cooking pot is used to keep heat from leaching into the box’s floor.

Examples of these type of cookers are:
The All American Sun Oven (Global Sun), SunCook, SunFocus, Solavore Sport (SOS Sport)

The All American Sun Oven (Global Sun)

The All American Sun Oven is manufactured by Sun Ovens International. Formerly this model was called the Sun Oven, or sometimes the Global Sun Oven. In 2013 the model was updated with a 20% larger internal cooking area to allow for more common size baking pans. The new design also has added wind resistance features.

The cooking chamber is 14” square, about 11” deep in the back, and 8” deep in the front.

SunCook

The Sun Cook is a concentrator type solar cooker with many solar box cooker characteristics. It weighs just over 24 pounds (11 kilograms) and has a cooking area of 13.8 inches by 16.2 inches (35 centimeters by 41 centimeters).

The Sun Cook’s unique system of external, anodized aluminum reflectors directs addition sunlight onto the absorber plate and cooking pot. The primary reflector, which can be vertically extended via a slide-out mirror, is attached at the back of the cooker’s lid. The second reflector can be attached on either side of the lid, and fans open to accommodate the primary reflector’s tilt.

Oven-type insulation is used inside the box and below the absorber plate. The Sun Cook’s “window” is double glazed with tempered glass and sealed to prevent moisture infiltration.

If needed, cooking times can be controlled by a unique solar “clock” that works in conjunction with the side reflector to cast a shadow across the cooker after a specified period of time.

SunFocus

The SunFocus Solar Electric Oven with an electric back-up cooker option. The SunFocus solar electric oven’s electric heating elements is rated at 465 watts / 120v. It has a built-in thermostat which will turn off the electrical heating element once the cooker has reached 150°C (300°F).

This solar cooker has a molded plastic exterior shell. The oven has double panes of glass, gasketed with EPDM rubber gaskets for a tighter fit for greater heat loss retention. The cooking chamber has a fairly large cooking area16.5 cm (6 1/2″) deep with upward sloping sides 13.5 cu/in. at the bottom and 20 cu/in. at the top of the cooking chamber.

The SunFocus oven is designed to sit on a flat surface, it’s back reflector adjustable to angle the sun’s energy into the cooking chamber and the two side reflectors are stationary at a 50 deg. angle. It relies on the electrical back-up on cloudy days or when the sun is low in the sky, or for winter cooking in higher northern latitudes.

Solavore Sport (SOS Sport)

The Solavore Sport is amazingly effective because of its innovative design features. The cooking chamber is 9 1/4” x 17 1/2” x 10” at back and 4” in the front. Good insulation is the most critical requirement for a great performing solar oven. The Sport insulation has an excellent R 6.5 value. It is reinforced with glass fibers to protect it from heat degradation and help it resist crushing.The Sport insulation material will not absorb water. It is composed of thousands of tiny, sealed, air holes that water cannot penetrate. This is a key design feature because moisture is always present in solar cooking as steam and humidity.

Exclusive Insulated Top. All solar ovens must let in sunlight. Most designs lack insulation in the lid resulting in heat loss during extended cooking times. The Sport lid is insulated with an innovative, exclusive, 1-inch air gap between the thicker molded lid and the taped on plastic film.

No Tip-Over
Tip-over from wind, rough terrain or slope can be a major issue in solar cooking. The broad footprint and low center of gravity of the Sport make it aerodynamically and physically stable.

Optional Reflectors
The Sport comes with optional higher grade polished aluminum reflector panels that will last a lot longer than the original corrugated plastic adhesive reflector panels that were with the oven from the beginning, this is a major upgrade.

Advantages

Disadvantages

General characteristics

Can cook multiple pots simultaneously

  • Can be built from many different materials
  • Can cook large quantities of food using multiple pots simultaneously
  • Most modes rarely have to be turned to follow the sun while cooking
  • Can be used to bake breads and cakes

Can’t fry foods

  • Simple box cookers may lack adequate reflector area.
  • The box may shade the cooking pot when the sun is lower in the sky. Manufactured box cookers often have a mechanism to tilt the cooker forward, while maintaining a flat cooking tray.

 

Comparison Chart
Scale 1 (Bad) – 10 (Good)

Cooking chamber*

Outside dimensions

Weight

MSRP

Comments

All American

14x14x11-8

22 x20x12

23lb

$349.00

Many accessories available

SunCook

22x20x12

16.5x14x7

28lb

$459.00

Many accessories available

SunFocus

13.5 x13.5x 6.5

22x22x12

30lb

$564.00

This is a hybrid cooker

Solavore

9x13x8-4

12x15x8

15lb

$229.00

Reflectors available

*measurements are in inches. The last two hyphenated numbers are the measurements of the back and front of the cooking chambers.