Sensors and Feedback

Sensors that work with feedback systems easily and automatically conserve energy. Energy sensors monitor the use of electrical and heat energy within a room or an entire building. Sensors can be used in two different ways to conserve energy. First, they monitor a building’s peak and nonpeak times of energy use and so identify the periods in which a structure puts more or less stress on a community’s power grid. Second, on-off sensors such as motion sensors turn indoor or outdoor lights on when they detect motion and off when the area is no longer being used to reduce energy waste.

A wood stove generates heat without
using electricity. Stoves and fireplaces
conserve a house’s solar power and avoid
the need to draw from the municipal
power grid. Wood is a type of biomass
that produces an equivalent amount
of Btu as crop wastes, which are also
combusted for energy production. (Jotul)

Sensors in combination with feedback systems provide even better control of energy use because a feedback system tells a building’s residents how efficient they are in using energy. A sensor- feedback system contains two components: the detection unit called a transmitter that may be attached to an electrical or gas utility meter, a water meter, or a thermometer, and the display unit located inside the house, which receives wireless signals from the transmitter. Sarah Rich wrote for the online environmental magazine WorldChanging, “It’s one of those telling facts of human nature that when we are being monitored, our behavior changes.” Just like a speedometer in a car, people self-monitor when they receive helpful information. “The same holds true in households,” Rich explained, “where inhabitants can be made immediately aware of their energy consumption. If you can see your pennies piling up on account of a light you left on in the bathroom, you can bet you’ll remember to turn it off.” These so-called smart sensors offer one of the simplest ways to manage energy use.

New systems make energy savings even easier for people to save energy. Hotels or homes can be equipped with key cards that contain information on the indoor heating, cooling, and lighting systems. As a person enters a room, inserting the card into a small slot box near the door, lights and other systems turn on to make the environment comfortable, with heat, air-conditioning, or ventilation. The person simply removes the card from the slot when they leave, and the systems readjust to energy-saving mode. Sensors and automatic on-off switches are inexpensive, and the electricity savings make up for the price in a short period of time.