The SunRocket is designed to heat water entirely via the sun. No doubt an appealing concept, but does it actually accomplish this task? We found out when we put it to the test on some swelteringly hot days.
The SunRocket retails for $59.50. It has two reflective aluminium panels that fold out from the body to absorb solar heat. The panels cleverly stay firmly in place by clipping onto the rotatable carry handle which also acts as the stand. When we want to fold the panels away they simply snap together via reliable magnets, and there is decently rugged plastic securely wrapping the product. The appearance of the SunRocket when lying on the ground heating water, and when being carried around by the handle, is rocket-like, and the red reflector on the screw cap with pressure release valve definitely cements the image.
Keeping the water insulated is a Vycor glass evacuated tube. This means that the water, once heated, will diminish in temperature very slowly, so you can use it hours after the appropriate temperature is reached; and the folded aluminium panels apparently further aid the thermo effect. An early onset disappointment was that the tube only holds 500ml/17oz of liquid, not even enough capacity to make two cups of coffee. But the more water to heat, the longer it takes, or so we assume.
To put the SunRocket to the test we filled it with cold water from a tap, set it up outside directly underneath the sun on a blue sky day with temperatures of around 24°C/ 77°F. After the first 30 minutes of the SunRocket being left outside not much happened, although the temperature of the water had dropped a little and had become mildly warm. A further 30 minutes later and the water was lukewarm. After a total of 120 minutes we opened the cap and found steam pouring from the SunRocket, and so our scepticism of the product immediately faded at this point.
We couldn’t even keep our finger within the water for any lengthy period as it would definitely get burnt, but had it reached boiling point? To answer that bluntly, no. Boiling point is 100°C or 212° F and the water within our SunRocket had reached 81°C/ 179°F. Still hot enough to have a cup of coffee, wash dishes and use to rehydrate foods but, of course, at boiling point you'd be able to sterilise water from rivers and the like. And we believe if we were in a warmer climate boiling point would have been reached.
Obviously not as quick as an electric kettle by any means, but when you’re away from mains electricity, and in an environment with plenty of direct sunlight, the SunRocket truly provides a portable water heating solution for the likes of campers or hikers which genuinely works.