The Matrix Data Bank

One of the easier methods to save money, is to reduce your energy consumption…  But beware, this is a area of diminishing returns…  Yes, automating your hot water heater, to turn off the heater when not in use will save quite a bit of power, but you end up having to wait for the Hot Water to be available…  Instead a Tankless hot water heater might be a better choice…

Also, all of the Automation devices have a slight power draw…  But more on that later in this page..

Identify your Power Usage

First, you need to identify how much energy a item is using. For most devices you can just look at the label! Nearly everything you can plug into the wall has a label that says how much electricity it uses. (It may be printed directly into the plastic or metal.) You may have to hunt for the label. It’s often located on the bottom or side of the device, or possibly where the power cord enters the unit. If the device is powered with an AC/DC adapter, the electrical rating is usually listed on the adapter itself.

If the label only gives the number of amps and not the number of watts, then just multiply the amps by 120 to get the number of watts. (Amps x Volts = Watts, and most U.S. electricity is 120 volts. So a hot plate that uses 6 amps uses 6 x 120 = 720 watts. Most other countries use 240 volts instead of 120, so outside of North America and Japan use 240 instead of 120 in your calculations.) Note that if a device is powered by a transformer (one of those great big plugs), then the transformer has converted the electricity from AC to DC, so you need to multiply by the DC voltage, not the AC voltage of 120. For example, if the device says “INPUT 9V, 0.5A”, then that’s 9 volts x 0.5 amps = 4.5 watts.

You may have noticed that appliances may be labeled 110, 115, or 120 volts. Appliances are actually designed to accept a range of voltages, between 110-120 volts, and the exact voltage coming out of your electrical socket can vary depending on conditions at the power plant and in your own home. Let’s just agree that when we say 120 volts, we understand that it’s actually a range from 110-120. And just use 120 for your calculations (unless you’re outside of North America or Japan, in which case you probably have 240 volts).

Your device might actually list a huge voltage range, like 100-240V. That just means that it will work with any country’s voltage. For your calculations, use the voltage for the country where you’re plugging the device in.

Some important caveats:

1. The amount of electricity listed on the label is the maximum amount that the appliance will ever use. For example, a 300-watt refrigerator will only run at 300 watts when the compressor’s running (which is when it makes that humming sound, indicating that it’s actually chilling the air inside). Most of the time the fridge just sits there, using only 5 watts or so for its electronics. If the amount of work done by a device varies up and down, then so does its energy use. (e.g., a stereo that can be turned up or down, an oven that can be set at various temperatures, a fridge that sometimes runs and sometimes doesn’t, a computer that sometimes spins its various drives and sometimes has to use more of its brainpower, etc.) The label on computers is particularly useless; a computer labeled at 300 watts probably uses only about 100. In just a bit we’ll cover how to measure the actual amount of electricity being used by a device.
2. Many consumer items are advertised according to their power output, not input.That means the stereo that says 30 watts on the box might actually require 50 watts to make 30 watts of sound (assuming the volume was cranked), and your 900-watt microwave oven might actually use 1400 watts (on its highest setting). That’s because all electrical devices are inefficient — they have to use some extra energy to do what they do.
3. Knowing how much electricity a device uses at a given moment doesn’t tell you how much it’s using in a month, because it’s probably not running 24/7 (and if it is running 24/7 like a fridge, it’s probably not using the maximum amount of electricity, as we discussed earlier). To measure how much electricity something uses for a certain period of time (like a week or a month), you can use a watt-meter.
4. Some devices use a small amount of electricity even when they’re not on. For example, VCR’s and microwaves draw a small amount to power the time display. This amount is often 5 watts or less. Devices which run off transformers also draw a small amount of power.

And of course, electricity consumption of a device varies from brand to brand, and condition to condition.

Electrical usage of household items

Of course, knowing that your refrigerator uses, say, 350 watts when the compressor’s on doesn’t tell you how much energy it uses in a month, because the compressor’s not on 24/7. The chart at right shows how the average home used energy (not just electricity) in 2007. (Source: Dept. of Energy) Of course, air conditioning uses a bigger chunk of the pie in the summer. According toAustin Energy, AC accounts for 60-70% of the average home’s summertime power bill.Here are some websites that give sample costs for various household items considering how much those items are used:

• University of Nebraska-Lincoln
• Seattle Light
• Cornhusker Public Power District

As a general rule, Appliances that create or remove heat use the most electricity.

Heating

• 26,500 watts   Elec. furnace, 2000sf, cold climate
• 7941 watts        Elec. furnace, 1000sf, warm climate
• 1440 watts       Electric space heater (high)
• 900 watts         Electric space heater (medium)
• 600 watts         Electric space heater (low)
• 750 watts         Gas furnace (for the blower)

Cooling

• 3500 watts       Central Air Conditioner (2.5 tons)
• 1440 watts       Window unit AC, huge
• 900 watts         Window unit AC, medium
• 500 watts         Tiny-ass window unit AC
• 750 watts         Central AC fan (no cooling)

More efficient cooling

• 350 watts         Whole-house fan
• 100 watts         Floor or box fan (high speed)
• 90 watts            52″ ceiling fan (high speed)
• 75 watts            48″ ceiling fan (high speed)
• 55 watts            36″ ceiling fan (high speed)
• 24 watts            42″ ceiling fan (low speed)

Major appliances

• 4400 watts       Clothes dryer (electric)
• 3800 watts      Water heater (electric)
• 200-700 watts  Refrigerator (compressor)
• 57-160 watts   Refrigerator (average)
• 3600 watts       Dishwasher (washer heats water)
• 2000 watts      Electric oven, 350°F
• 1200 watts       Dishwasher (washer doesn’t heat water)

Lighting

• 60 watts            60-watt light bulb (incandescent)
• 18 watts            CFL light bulb (60-watt equivalent)
• 5 Watts             Night light
• 0.5                      LED night light

Computers

• 150-340 watts  Desktop Computer & 17″ CRT monitor
• 1-20 watts         Desktop Computer & Monitor (in sleep mode)
• 90 watts             17″ CRT monitor
• 40 watts             17″ LCD monitor
• 45 watts             Laptop computer

Televisions & Videogames

• 270 watts              42″ Plasma television
• 210 watts              42″ LCD television
• 125 watts               32″ LCD television
• 55-90 watts          19″ CRT television
• 45 watts                 HD cable box
• 194 watts               PS3
• 185 watts               Xbox 360
• 70 watts                 Xbox
• 30 watts                 PS2
• 18 watts                 Nintendo Wii

Other

• 1440 watts            Microwave oven or 4-slot Toaster
• 900 watts              Coffee maker
• 800 watts              Range burner
• 4 watts                   Clock radio
• 3 watt-hours         Total power stored by an alkaline AA battery. This is to put batteries into perspective.

Remember that electrical usage varies from model to model, so remember that the tables on this site are just examples.

How Can Home Automation help save Energy?

• Home Automation can save you money, but unless the device is horrible inefficient, you need to keep in mind that this will be over a period of time.
• Concentrate on the “big ticket” items first, items that have the most energy draw, since they will return the most savings to you.
• Beware Diminishing Returns, as you identify and address the “big ticket” items, you will be eventually reach devices that are lower draw.  Make sure that they need to be addressed, after all the Home Automation hardware has a ~1 Watt draw, so if the item only draws a few watts, it might be cheaper to not address the issue.
  • Alternatively, see if you can gather many of the transformer powered devices together, and automate the power strip that they are plugged into.
• Take a look at your usage patterns, see what needs to be addressed?
  • For example, do people forget to turn off certain lights?  If so, setup a timer that activates when the light is turned on, when the Timer expires, turn off the light via the Home Automation software.
  • Do certain devices only need to be turn on at a certain time?  And turned off later?  For example, a Child’s night light?  (With Indigo, turn on 30 minutes before sunset, and turn off, half an hour after sunrise.)
  • If you are not using CFL (Compact Florescent Lights), can you operate the bulb at a dimmer setting?  If so, do so.
  • Do you have a Mud Room, Foyer, etc?  By using either a motion sensor, or a door sensor, you could have your lights in that room turn on when the door is opened, and turn off after a few minutes (7?) after you have left the area.
  • Do you have a Geothermal Heater?  Whenever the Geothermal unit runs (either AC or heat), it dumps the excess heat from the Geo unit into the water heater, so whenever the Geothermal unit turns on, have Insteon turn off that water heater and then turn it back on within a certain period of time. If the Geothermal runs again before that “time to off” expires, it resets the water heater timer. During the extreme hot and cold days when the Geothermal unit runs constantly, the water heater never turns on.
• Remember, the number one goal of Home Automation is not necessarily to save money, but to make your daily activities easier, more productive, and smarter!

• When you open a door, why shouldn’t the room/home automation turn on the lights for you?
• Why shouldn’t you be alerted when an outside door is opened?
• etc…etc…

Estimated Energy draw of Insteon Hardware

This has been difficult, since Smarthome has not specificied what the energy draw is of the Insteon devices….  And their draw is so low, that it is hard to get an accurate reading…

• The Dual Band Lamplinc’s appear to draw roughly 1 Watt or Less of power.  (1 Volt-Amphere, 0Watts, Power Factor of .8)
• Dave houston did a long term Kill-A-Watt measurement of a variety of SmartHome devices
  • AM486 0.4W  (X10 Appliance Module)
  • LM465 0.5W  (X10 Lamp Module)
  • TM751 1.2W  (X10 Appliance Module / Radio Transceiver)
  • RR501 1.4W (X10 Appliance Module / Radio Transceiver [16 device])
  • CM11A 1.3W  (X10 Computer Interface)
  • CM15A 0.93W  (2004 X10 Computer Interface with Integrated RF transceiver)
  • 1132B 1.2W     (SmartHome’s PowerLinc Controller for X10)
  • 2412S 0.9W    (Smarthome’s PowerLine Modem for Insteon/X10)
  • 2414S 0.9W    (Smarthome’s PowerLine Controller for Insteon/X10, with integrated Clock for Stand-Alone mode)
• So the 2412S & 2414S seem to draw roughly .9 Watts, the non-dual band lamplinc draw approx. 1 Watt, and the dual band lamplinc draw “supposedly” 0 Watts, but probably less than 1 Watt, and an rounding error… (Kill-A-Watts are suppose to be accurate to roughly 1 Watt, but….)
• So, the evidence suggests that the modern unit would draw roughly 1 Watt, after all the X10 units are older technically and generally less energy efficient, and out of 9 units only 4 are above 1 Watt, so roughly 60% are under 1 Watt…