Solar at Home

Solar at Home

The trials, tribulations and rewards of going solar

Tools for doing your own energy audit


Editor's Note: Scientific American's George Musser will be chronicling his experiences installing solar panels in Solar at Home (formerly 60-Second Solar). Read his introduction here and see all posts here.

The last piece of my solar array fell into place three weeks ago when the utility installed two new meters on my house, one that registers solar energy generation (for determining tradable credits) and one that registers net home consumption (for billing). So far, my array has produced as much as 8.1 kilowatt-hours per day, which is actually a bit more than the PV Watts calculator predicts for a system of my size (3 kW). But the job isn't over yet. It may never be.

Fighting energy waste is a never-ending battle. In an earlier post, I mentioned The Energy Detective, which measures the total electricity consumption of your house. To track down specific power hogs, a portable meter such as Kill-a-Watt is invaluable. With it, I recently went around the house checking how much power our electronic appliances and adaptors consumed in standby mode. Bracing myself for a torrent of waste, I was pleasantly surprised that most devices drew less than one watt.

The suckiest vampire proved to be the Wii (10 watts in standby mode), so we're more diligent now about powering it down. A handheld-vacuum charger drew three watts even when the battery was full-up, so now I make sure to unplug it between chargings. A USB hub and UPS each drew 2 watts, and we didn't really need either, so we removed them. It's not much, but it adds up, and it's easy to fix.

With an Amazon gift certificate my mom gave me for Christmas, I got another handy tool: a Black & Decker Thermal Leak Detector. An affordable version of the multi-thousand-dollar thermal imagers used by professional home energy auditor, it gives temperature readings, though not full thermal images. And boy is it great! Best gift my mom ever got me.

The sensor resembles a laser-tag pistol. You point it at a surface, a readout tells you the temperature, and—here's where it gets fun—a laser pointer changes color to red, blue, or green depending on whether the temperature is hotter than, colder than, or equal to a reference temperature (namely, the temperature of whatever the detector was pointing to when you turned it on). So you can see at a glance where heat is leaking out. A switch lets you set the amount the temperature needs to deviate from the reference for the light to change color.

The image at the top of this post shows two readings on the wall above a window in my daughter's room. It matches the thermal image taken by my auditor. I've already found lots of places to caulk or insulate. Best of all, by taking before and after readings, you can see what good your efforts have wrought. For instance, the light turned blue when I passed the sensor over an outlet, so I added a sealer under the wallplate—and the temperature jumped by six degrees F. With all the work we've done to button up our house, I appreciate having some proof it actually does some good. 

Black & Decker thermal sensor reading in George's house, courtesy of George

The views expressed are those of the author and are not necessarily those of Scientific American.

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