To get you started with the #EnergyChallenge here’s some tips on creating energy-saving automations and calculating annual savings.
There’s many ways to connect devices to save energy, money and the environment. A good place to start is to first identify the devices that use the most energy in your home. The next step is to think about how you can connect them in ways that save energy. Broadly speaking there are 5 automation categories, from simple to sophisticated, that you should consider:
1 - Button widget
Connect your devices to a virtual button on your smartphone. Manually pressing the button triggers an action to turn off your connected devices.
2 - Date & Time service
Connect your devices to a Date & Time service. The service will automatically turn off your connected devices, at a designated time when they are not in use, or when electricity becomes more expensive.
3 - Location service
Connect your devices to a location service on your smartphone. The service will automatically turn off your connected devices when you leave a certain location like your home.
4 - Local sensor
Connect your devices to a local sensor like a motion detector, camera or thermostat, so that when the sensor is triggered it automatically shuts off your connected devices.
5 - External service
Connect your devices to an external service like weather or energy prices, so that when the sensor is triggered it automatically shuts off your connected devices.
Calculating annual energy savings
The first step to calculating energy savings is to understand the cost of running the device/s before your automation. Energy consumption is calculated in kilowatt-hours (kWh) which equals the power rating of the device in watts, by the number of hours in use, divided by 1000.
For example a 100 watt light that runs daily for 10 hours consumes 1 kWh of energy (100X10/1000). Over the course of 1 year that would be 365 kWh of energy consumed. In the USA the cost of 1 kWh is approximately $0.14, so the total cost of running that light annually is $51.10. (100X10X365/1000)X$0.14.
Example 1: Using lights only when needed
Let’s use the above example, so again the cost of running a 100 watt light for 10 hours every day is $51.10 annually.
Connecting the light to a motion detector means that the light now runs on average just 1 hour per day, which is 10% of the consumption before the automation or $5.11 per year. Therefore the total annual savings for the automation is $45.99 ($51.10 - $5.11).
Example 2: Shifting energy consumption to Off-Peak hours
Another resource for calculating savings is your local utility. In this example, PG&E, a utility in California, publishes the cost of running an average dryer per cycle (Peak is $1.59 & Off-Peak is $1.34). So runnning a dryer once per day during Peak hours has a total cost of $580.35 ($1.59X365).
Connecting a smart plug and a Date & Time service prevents the dryer from being run during Peak hours (4 to 9pm). Instead the dryer now only runs during Off-Peak hours, so with each cycle, $0.25 ($1.59 - $1.34) is saved or $91.25 annually ($0.25X365).
- 5 ways to save with Smart Home technology (Automate Your Life - YouTube)
- Monthly Appliance Energy costs (PG&E California)
- Appliance Energy Calculator (Energy.gov)