# Whatever We Think, The Odds Seem To Be . . .Nine to one against (until we do our homework)

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I drink a lot of coffee around here, but minimizing electrical use is something we take seriously. Marie and I put our money on the table, and now there's 4.7 KW of solar panels on the garage roof. But it's not there to enable us to use more juice. On a sunny day in Syracuse we feed electricity back into the grid. And yes, we do get sunny days. When that happens, the meter runs cheerfully backwards, we save some money, and the coal burning and nuclear power plants need to work just a teeny bit less. As you know, I'm convinced that every little bit helps.

We're still fussy about conservation, so I thought about cutting back a few watts by turning off the heater under the coffee pot and just heating the next cup in the microwave. Sounds like it makes sense, right? Wrong. Really wrong!

Having begun to think along these lines I realized it was time to find out. The Watts Up? meter measures and calculates a number of different performance details about electrical appliances. It told me that the heater on our particular coffee maker uses 0.1 watts keeping the pot warm, and the microwave uses 1365 watts while heating a cup of coffee for one minute. Yikes! I was way wrong. And electrical usage is a huge issue.

What's the take-away? There's a far greater connection between building performance/remodeling and the scientific method than we think about. Before we make recommendations to our clients we should be sure that we are, at the very least, offering them the option that gives the best result for them, for their children, and for the planet.

Please. Do your homework by learning yourself or by following the recommendations of those who did.

*Update: An alert (but anonymous) reader has pointed out that 0.1 watts is an implausibly low number for keeping the coffee pot warm. He's right. Watts are units of power. Energy is power applied over time, so watt-hours or kilowatt hours are measures of energy.

The pot warmer is not necessarily using energy all the time. The 0.1 watt reading was the "vampire load," a term used to describe small amounts of energy to run clocks and so on in otherwise idle electrical appliances and devices.

It is in fact thermostatically controlled, and when the temperature drops below a certain point the heating element kicks in and returns the hot plate to something around 300°F. I put some ice cubes on the hot plate and, when the temperature fell toward 150°F, sure enough, the heating element turned on and ran and delivered 940 watts until the thermostat was satisfied.

So what does that do to the premise of my earlier experiment? We don't know the real answer until we know how long the coffee pot heater runs to keep the temperature of the coffee where we like it so we can compare that amount of energy to what is used by the microwave to achieve the same result. It's more complicated than I thought. (What else would you expect from an English major?)

So why do I love it that it turned out this way? Because it demonstrates the superiority of science (propose, test, verify, reproduce results), it reminds us that interactions of systems are complex, and it reaffirms the title of this blog: The Odds Seem to be Nine to One Against (until we do our homework)!

• Posted by: evoytovich | Time: 5:24 AM Thursday, April 21, 2011

From Ed's *old* friend, electrical engineer Joh Stratakos: My 4-cup (20 oz) coffee pot uses 565 watts when it makes and/or heats coffee. It consumed 50 watt-hours to make a pot. To keep that full pot hot for 2 hours consumed 120 watt-hours for a total of 170 watt hours or 0.170 kwh. From an esoteric view, coffee that’s been heated gets strong due to evaporation of the water. I typically use a microwave to heat coffee. 10 oz cup take 1 ½ minutes or 32.5 watt-hours.

• Posted by: Anonymous | Time: 8:26 AM Monday, April 18, 2011

How could 0.1 watt be right?

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