Robin Green

We've been bullfrogpowered since December 2005. Switching to 100% green electricity did not make us complacent about our energy use. After consulting a solar and conservation engineer, we identified several energy saving opportunities in our house.

Our first action was to buy a Kill-a-Watt meter, a device which contains a male plug on one side and a female plug on the other. You plug it into a wall socket, and then plug an appliance or any other 120-volt electrical device into it, and it tells you the voltage, wattage, amperage, time of use and kilowatt hours (kWh) used. We went around the house and measure the wattage or kilowatt hour usage of every electrical item we have plugged in and had some interesting findings.

Our computer equipment used about 50 watts. The printer itself was usually off but that did not stop its power supply from drawing 18 watts continuously. By puttin gthese devices on a power supply bar and turning the power bar on only when they are needed (at most, 8 hours a day) we save at least 0.8 kWh per day. Between a TV set and a DVD player, left off but plugged in, we were drawing 25 watts. We only watch one DVD a week and we don’t watch regular TV at all. Unplugging the TV and DVD still saves us 0.6 kWh per day.

We own a digital indoor/outdoor thermometer with a probe that allowed us to monitor the minimum and maximum temperatures in our refrigerator. Dipping the probe into a jar of water helped to provide a more stable reading of temperature than measuring the air in the refrigerator, which can swing wildly. We adjusted the cooling level until it reached 4°C (it started off at around 3°C), reducing the energy usage of the unit. We did the same for our fridge freezer, adjusting the temperature from –25°C to the recommended –17°C. By restoring the temperature to –17°C we cut the unit’s use even further. We did the same measurements on our chest freezer and trimmed its usage too.

Next, we got a rough estimate of usage by large appliances such as the stove (which at 220V you can’t measure with the Kill-a-Watt) and dishwasher (which has an inaccessible plug in our case). To measure these we got an accurate reading off our hydro meter immediately before baking a meal or washing a load of dishes, then measuring again after. The difference gives a rough estimate of usage. Baking a single tray of cookies uses over 1 kWh; baking 5 trays doesn’t use that much more.

Baking a loaf of bread in the bread maker uses 1 kWh. A load of dishes uses about 1 kWh (an Energy Star® appliance uses less). Just by being conscious of what these appliances use, we’ve cut our reliance on them somewhat, and therefore reduced energy usage. By unplugging our coffee machine, coffee grinder, and bread maker we reduced draw by about 0.5 kWh per day.

Finally, we measured daily energy usage by getting a reading each day from our outdoor meter in order to calculate usage and running averages.

Measurement is critical to conservation. When you see what you are using on a daily basis, you start to notice dips and spikes, and you can think about what different activities might have caused the dip or spike. A spike might mean a freezer door was left open in the workroom and no one noticed, and a dip might mean your decision to stop using a particular appliance, or at least unplug it when not in use, had a positive effect. Even before this process, we were already pretty low on the electricity usage scale, at 11 kWh/day for a two-adult, two-kid household, or about one third the Ontario average. But with careful monitoring and some simple changes, we’ve been able to cut our usage down to around the 8 kWh/day or 248 kWh per month, which is about a quarter of the average monthly usage in Ontario.

Visit Energy Efficient Homes, Robin's website.