Power Usage Monitors

Details

Currently there are 3 major home energy monitoring systems on the market:

• Power Cost Monitor
• Energy Detective
• Black and Decker Power Monitor

Each of these are designed mainly to monitor whole house energy use in real time. You can enter your unique utility rate structure and most of these devices will calculate your predicted utility bill (and show your real time consumption in dollars instead of kWh). Each costs between $100 and $200. A certified electrician should install the monitor (they go into your electrical panel) — it should take them about an hour's worth of labor.

Out of the three, the only monitor that can give circuit specific information is the Energy Detective. To do this, you will need to purchase additional current sensors. A full package including the monitor, display and 4 current sensors (one for the main line and three for the circuits of your choice) costs $455.80! Additional sensors beyond that cost $84.95.

There is equipment that can monitor all circuits simultaneously, but it is even less affordable for homeowners. This equipment is better suited for an electrician contractor who can conduct a comprehensive load analysis. There are energy efficiency minded electricians who can offer this service for a fee. They will also inspect the panel for lose connections, hot wires, and other safety issues. This will, however, only give you a snapshot of electrical usage — not an ongoing picture.

Another device that can help is the Kill-o-Watt meter. It can monitor the power consumption of an individual appliance. It costs about $50. It is restricted to 110v and there is no similar product for 220v appliances such as stoves and clothes dryers.

There is also one useful (and free) database for estimating electrical usage of the refrigerator, the most power hungry appliance in most houses.

So... Is Monitoring Worth It?

Is all this gadgetry another fancy tool to show off? Another thing to buy and a way for a company to make another buck off you? Does it distract us from real, strategic energy savings?

Most of the Home Monitoring Systems companies claim multiple studies show these devices will help you save 10-20% off your electrical bill. This is misleading. There has only been one study conducted using the Power Cost Monitor. It was published in 2006 by Dean Mountain, a professor of economics at the McMaster Institute for Energy Studies in Hamilton, Ontario. The study analyzed 500 households in Ontario and concluded that houses heated with electricity demonstrated an average reduction in usage by 1.2% as a result of the power monitors being in place. Houses heated by other means showed an average reduction of 8.2%. (Why did the non-electrically heated houses have a larger reduction? Because they used less electricity to begin with!)

These tools may be fun to learn about how energy is consumed in your house. If your family tends to leave appliances and lights on, your household may really benefit from this education. But if you want to actively reduce electricity usage, instead of just monitor it, you could also benefit from motion-sensor light switches, energy star appliances and smart surge protectors.

In general, most people would be better off first spending their money on real measures that reduce usage:

• Air seal your house
• Add insulation to your attic, walls and floors
• Buy Energy Star rated appliances (especially for fridges and washing machines)
• Upgrade your heating system

If you're not sure where to start, consider hiring an energy auditor who can provide you with a comprehensive, prioritized list of to-do's that are specific to your home.

The author of this article, Charlie Rogers, is the owner of Habitat Home Energy Audits, an energy auditing company based in Seattle. Charlie is a BPI Certified Building Analyst and PTCS Certified Duct Technician. You can get in touch with Habitat Home Energy Audits through their website or through the EnergySavvy network.

Last Updated: January 2010

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