Monday, July 30, 2012

Experiment: How long does it take a Presto electric teakettle to boil water?

Presto electric teakettle
Presto Electric Teakettle Experiment Background
I decided to do an experiment and see how long it takes this Presto electric teakettle to boil water. My wife drinks a lot of hot beverages and she likes to use this plug-in kettle to heat the water for her favorite mixes. Hopefully after testing the electric teakettle compared to our microwave I can conclude which method is most energy efficient.

Our electric teakettle is a 950-watt Presto model. The base is stamped with the model number 0270404 and also printed with the sequence 3610_2_T2, whatever that means. It is about 7.75" in diameter and about 5.5" high. The lid has a timer for steeping your tea. There is also a removable wire mesh basket for putting tea leaves directly into the kettle which I will not be using for this experiment.

electric teakettle experiment
My Pseudo-Scientific Experimental Method
Above is my "experimental method." I have 350mL of regular tap water (about 1.5 cups or 12 ounces) in a measuring cup, an NSF-certified digital kitchen thermometer, my iPhone's stopwatch, and the Presto electric teakettle. I chose 1.5 cups since it was enough to submerge the heating element inside the teakettle and is a realistic amount for putting in a 16-ounce travel mug with the drink mix without overflowing.

Taylor kitchen thermometer
To establish a baseline, I measured the temperature of the tap water. It was a mix of hot and cold water, since I didn't think it was fair to test with pre-heated water from the hot side of the tap. As you can see, our water started at 91.5 degrees Farenheit. The teakettle has not been used yet today and is at room temperature, abut 78 degrees F.

presto teakettle test
After taking the temperature reading, I immediately poured the water into the teakettle, popped on the lid, and plugged it in. There is no on and off switch on this electric kettle. When it's plugged in, it's on, when it's unplugged, it's off, which I guess means fewer parts to wear out and makes operating it when you're still craving that shot of caffeine in the morning a no-brainer. Anyway above is a picture of the test after one minute. The temperature has risen to just above 140 degrees F (if we trust the analog thermometer cemented into the teakettle wall.

electric teakettle temperature gauge
Here's a closer image of the dial on the teakettle itself. Because this is the model with the included tea basket, it also has a color-coded scale showing the recommended water temperatures for steeping various teas at right on the gauge.

Above is the test at completion. The water in the kettle has reached the boiling point according to the dial gauge. My digital gauge was temporarily shorted out in the hot steam shooting out of the spout, so I was not able to get an accurate reading there. The temp probe also is barely long enough to reach the liquid inside the kettle, so the reading wouldn't have been the best anyway.

The Result
The result is: it takes about 2 minutes 22 seconds to raise the temperature of 1.5 cups of water 120.5 degrees in the Presto electric teakettle.

2 minutes and 22 seconds is equal to 0.0394444 hours. Using our 950-watt electric teakettle for that amount of time uses about 37.5 watts of electricity.

Of course, there is a substantial margin for error each morning. If my wife doesn't measure out the water and heats more than she needs, electricity use will increase. Likewise, if she uses a slightly cooler tap water energy consumption will increase. I suppose the ambient air temperature would also influence this equation slightly. So there are a lot of variables here, and instead of being able to conclude any relevant result in the real world, I think I am going to call it a day. Based on our above experiment, there are too many variables to determine if using an electric teakettle is more energy efficient than other heating methods.

To make a relevant conclusion, I would want to repeat this experiment just as performed above at least two more times and compare the result. Then I might try it with more or less water, and with different temperatures of water. With all that data in hand, we might be able to establish some "energy factor" of how efficient the teakettle is. Then we would need to repeat all the same tests with the next heating source. Given than the whole point of my experiment was to save energy using the most efficient means of heating, performing all those tests would be quite wasteful! I'm off to drink hot chocolate!

No comments:

Post a Comment