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Powering Down: Toward a 90 kWh month



In June 2010, my wife and I attempted to reduce our electrical usage to under 3 kWh a day (about enough power to light two incandescent light bulbs). Here's how we did it.

In June 2010, my wife and I attempted to reduce our electrical usage to under 3 kWh a day (about enough power to light two incandescent light bulbs). Here's how we did it.



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  • This is cheating a little, because it’s comparing year-round consumption to June consumption
  • Reduce electricity or keep things more comfortable
  • 14% of USA average; 19% of Chicago average
  • Saved $150 so far this year; on track to save about $200Doesn’t include natural gas (hard to track, since gas prices changed a lot)

Powering Down: Toward a 90 kWh month Powering Down: Toward a 90 kWh month Presentation Transcript

  • Powering Down
    Toward a 90 kWh month
  • Who are we?
    Will Emigh – number cruncher, analyst
    Maggie Sullivan – mastermind, implementer
  • SIREN contest
    Southern Indiana Renewable Energy Network
    Reduce 2010 usage compared to 2009
    We already did a lot in 2009; could we do more?
    Terminology: kW vs. Watt, kW vs. kWh
  • 2009 vs. 2010
  • Our goal: 90 kWh a month
    For the environment, what matters is how much electricity you use
    For comparison, it’s useful to look at usage per square foot
  • How much is 3 kWh?
    2 60-Watt bulbs on for a day
    A 20 year-old refrigerator in a day
    One load of clothes in the dryer
    A desktop computer and monitor on for a day
  • How does that compare?
    Based on average annual usage
    Adjusted to our home size
  • Pop quiz!
    How much electricity do these items use?
    Space heater
    Clothes dryer
  • Correct answer: how would I know?
    People overestimate low-usage items and underestimate high-usage items
    Unless it’s Energy Star, you probably can’t tell in the store
    A Kill-A-Watt can tell you for plug-in items
  • actual answers
    “Public perceptions of energy consumption and savings” by Attari, DeKay, Davidson, de Bruin
  • actual answers
    How much electricity do these items use?
    CFL 12 Wh
    Laptop 30 Wh
    Space heater 900 Wh
    Dishwasher 1200 Wh
    Clothes dryer 6000 Wh
  • Too many cooks
    There’s lots of advice out there
    Not all of it applies to our climate, home, or lifestyle
    Our rules:
    Track usage
    Try new things
    Measure specifically when possible
  • How might we differ from you?
    1350 sq ft house
    Gas heat & stove (although furnace still uses a lot of power for the fan)
    Work from home
    No kids (but a dog)
    No dishwasher
    Good house orientation (windows across from each other, south-facing windows, etc.)
  • Tracking (over 200 measurements)
  • Tracking
    I mark down current measurement, time, and comments every day after work
    Can buy real-time monitors, but they tend to be expensive
    Working with Ted Mendoza of Gengee to create an iPhone app to make it easier
  • Measuring
    Can’t tell what to focus on when you don’t know what’s working
    Kill-A-Watt works for normal outlets
    Larger items (water heater, furnace) can be estimated through tracking
    We turned off our water heater while on vacation to see how the base load changed
  • Heating/coolingare the biggest culprits
    Hot tub/pool heater
    Water heater
  • Pre-challenge, what did we do?
    No impact on our quality of life
    No major expenses
    No major effort
  • Low-power setting on laptops
    Desktop with monitor can draw 150 Watts
    Laptop draws 30 Watts
    Netbook draws 15 Watts
    Hibernation is less than 1 Watt
    Suspend uses effectively no energy
    Over 2 kWh per day for desktop on continuously
    Our average laptop usage: < 0.5 kWh
  • Power strips for almost everything
    DVD player
    Toaster oven
    Cable box
    Anything with a clock or a remote
  • Lighting: CFLs
    Cheap (often free through deals – check with your utility company)
    20% electrical usage compared to incandescents
    Produce less waste heat
    Reduced bulbs in fixtures (don’t need 4 bulbs in the bathroom at night)
  • high in the summer,low in the winter
    Set thermostat to 78 in summer (75 during the hour we’re trying to get to sleep)
    Set thermostat to 65 in winter (60 while asleep)
    Check utility company for deals on programmable thermostats
  • Post-challenge, what did we do?
    Made sacrifices
    Didn’t worry about whether we could maintain long-term
    Spent more money
    Tried more things
    Cut out tiny things just because we could
    Charged laptop during business meetings
    Stayed in the same room to reduce light use
  • New refrigerator
    Old one (17 years) drew 2.6 kWh a day!
    New Energy Star unit of same size uses 0.6 kWh a day
    Cost $700 minus some rebates (check with your utility company)
    Will pay for itself in about 10 years (less if rates go up)
  • No A/C
    Closed windows and blinds during the day, opened at night
    Fans set up to encourage air replacement at night and ceiling fan
    Cool water in fridge; ice pops in freezer
    Occasional escapes to A/C (movie theater, etc.)
    Got up to 82 in the house (prior to heat wave in July/August)
  • No dryer (line drying)
    Our dryer uses 4-6 kWh per load!
    No such thing as Energy Star dryer
    Set up drying rack for underwear/socks
    Used two lines that got good afternoon sun to dry everything else
  • Camp shower (Whoa!)
    Our water heater uses about 1-2 kWh to reheat
    We tried cold showers, but it was too cold!
    Purchased a kit at Dick’s Sporting Goods
    Black 5-gallon bag with spigot
    Plastic privacy barriers that hang from a tree
    Put a welcome mat underneath to keep feet cleaner
    Put bag in the sun in the morning
    Sometimes took bag inside to use, but it was unwieldy
  • Solar cooking
    Didn’t actually help much, since our stove is gas (but an electric stove draws 2.4 kW!)
    Sometimes replaced slow cooker use, which is about 600 Wh for ours
    Fun to put rice out in the morning and eat it at night
  • small solar charger for phones
    Take forever to charge
    Phones (even smart phones) don’t draw much power
    Not worth it unless camping or traveling
  • To infinity and beyond!
    On-demand water heater
    More efficient washer/dryer
    Solar water heater
    PV panels
    Light-colored metal roof
    Attic fan
  • Solar furnace!
    Our winter electrical use is 1.5-2x summer
    Furnace fan
    Harder to heat water
    Solar furnace fan uses 90 Watts
    Produces hot air continuously on sunny days
    Come visit on Sunday!
  • We did it!
  • Not sustainable
    We like taking showers in the morning
    Line drying isn’t always convenient
    Too many clothes
    Can’t be around to put them out/bring them in
    Sometimes it gets really hot!
  • Still, We’re doing well
  • Remember this?
  • What do we recommend?
    Focus on things that are on a lot
    Focus on things that draw a lot of power
    Check out new technology
    Energy Star refrigerators
    Solar furnace/water heater/panel
    Don’t worry too much about curtailment
  • Replace incandescent with CFLs
    No reason not to at this point
    Probably won’t save a lot, but the return on investment is high
  • Hibernate/Suspend computers
    Leaving a desktop on is worse than leaving a light on
    Leaving a laptop on is worse than leaving a CFL on
    Easy to change power settings
    Easy to hibernate/suspend when not in use
  • Replace old appliances
    Greatest change in efficiency in the last 10 years
    Water heater
    Clothes dryer
    Washing machine
    Efficient ones cut down on dryer time as well
  • Remove extraneous heaters/coolers
    A fridge in the garage
    A chest freezer
    Even a tiny dorm fridge uses almost as much as a normal one!
  • Solar water heating
    Makeshift (camp shower)
    Easy to setup
    Can shower in the morning
    Easier to shower inside
  • Line dry as much as possible
    Clothes dryers are TERRIBLE
    Line dry in the summer
    Line dry in the winter
    If you have to use a clothes dryer
    Make sure your washer is spinning most of the water out
    Vent heated air into the home in winter
  • How much are we talking?
  • Questions?