TMC is an independent, primarily volunteer organization that relies on ad revenue to cover its operating costs. Please consider whitelisting TMC on your ad blocker and becoming a Supporting Member. For more info: Support TMC

Where does all my power go?

Discussion in 'Energy, Environment, and Policy' started by derekt75, Jun 29, 2014.

  1. derekt75

    derekt75 Member

    Jul 16, 2012
    San Jose, CA
    I'm using over 2000 kWh per month and I'm curious where all that power is being consumed.
    Car: 600 kWh per month.
    Pool filter: ~300 kWh per month
    Pool cleaner/other pumps: ~200 kWh per month

    That leaves me drawing 900 kWh on other stuff, and that seems rather high.

    SolarCity and PG&E both allow me to download data, so I downloaded both files, combined the PG&E consumption and SolarCity consumption, and made the following graphs:

    The car obviously makes up the bulk of the energy usage at 1am. I have it set to draw a max of 30A, so that's why the power doesn't exceed 10 kW.
    The pool filter runs 9am to 9pm. The pool cleaner now runs about 13:30 to 17:00, but during the winter it stopped at 15:00.

    I'm surprised that air conditioning a big house doesn't seem to make June that much worse than other months.

    Any thoughts?
  2. meloccom

    meloccom Moderator Aus/NZ

    Feb 11, 2008
    Sydney Australia
    Start with the big draw items:
    How do you heat your water?
    Can you install window shading or plant a tree to reduce heat load in summer.
    How many refrigerators do you have and do you need them all?
    Then look for things that run all the time but don't need to can have timers added.
    Eg heated towel rails, stereo system, TV, computers.
    You can buy cheap power meters to look at the draw of your appliances.
    Move your car charging to later if possible so it finishes just before you leave each morning and its battery will be nice and warm in the winter and that will improve its efficiency.
    Good luck.
    Does your pool need to be cleaned every day?
  3. derekt75

    derekt75 Member

    Jul 16, 2012
    San Jose, CA
    Gas hot water.
    Two refrigerators, and yes, I want two.
    Hot water recirc pump running all the time.
    Several computers and several DirecTV receivers.
    Other random stuff like security (and baby) cameras also run all the time.
    Even though I have gas heat, I suppose the blowers for the furnaces are also a part of the overnight usage (and probably part of the reason why I use more nighttime electricity Jan-Mar than Apr-Jun).

    The overnight baseline (when not charging the car) seems to be about 1 kW. At first I was thinking that wasn't much compared to all of the bigger numbers on the graph, but I guess 1kW 24/7 adds up to 700 kWh per month. Maybe that is something I should look into.

    I might be able to back off a bit on how often the pool cleaner runs, but the skimmer is attached to the cleaner, and not running the skimmer results in stuff floating on top of the water.

    Next winter, I guess I'll try charging the car later.

    How does my usage compare to others with a pool? Is my pool using far more power than others? How about my overnight usage? How does that compare?
  4. omgwtfbyobbq

    omgwtfbyobbq Active Member

    Aug 24, 2013
    Southern California
    I think the fridges and recirc pump are about a third of that. If the receivers are older, they could be using as much as 40W each 24/7/365, and the remainder probably comes from the computers. My baseline is ~300W for one fridge, a pogoplug (server running archlinux arm), and a couple LED lights that are on pretty much 24/7.
  5. swaltner

    swaltner Active Member

    Oct 13, 2012
    Kansas, USA
    Depending upon the age of your central air/furnace, the blower can use as much as a kW of power. I have a power monitor in my main breaker panel. When the gas furnace is running, there's between 900 and 1,000 Watts used by the blower fan. In Dec 2013, my furnace ran 195 hours. Amazing how much electricity the gas furnace used....

    If you want to monitor power draw of regular 120V devices, pickup a $30 Kill-A-Watt. This won't monitor your 240V circuits (pool pump, tesla charger, etc). TED (The Energy Detective) sells a residential system that would monitor 17 individual circuits for less than $500. If you track the source of you usage, you can limit it. My house/hangar are currently consuming 395 Watts. 120 Watts is from the lights in the bedroom. Amazing how much power regular incandescent bulbs actually consume. The lowest I can get it without pulling power cords on TVs and the like is 200 Watts.

    I'm curious how many people are in the household and are some people there all day? My daily electricity usage jumped from 20 kWh to 35-40 kWh when i worked from home two weeks ago. The big difference was the AC was just left at a constant temp when I was working from home. Do you use a setback thermostat to adjust the furnace/AC set point when the house is empty?
  6. Robert.Boston

    Robert.Boston Model S VIN P01536

    Oct 7, 2011
    Portland, Maine, USA
    First off, your 900 kWh/month average isn't far off a typical household usage (though the average will include pool-related usage). But you're high for CA: the average California residence uses 573 kWh/month, compared to the national average of 903 kWh. (Here in Maine, we have the lowest average usage in the country, at only 531 kWh - no pools, very few air conditioners, and oil or NG heating.)

    It won't change your total usage, but consider running your pool cleaning gear before noon. In California, power demand and wholesale prices are higher in the afternoon than the morning.

    Your A/V system(s) could be drawing a fair bit of power; even on standby, plasma TVs use a lot of juice. Also, how old are your refrigerators/freezers/etc.? Appliance efficiency has risen dramatically in the past 10 years.

    I assume you've replaced all the incandescent lights in your house; try replacing halogens and others, too. LED prices are falling dramatically.
  7. mnx

    mnx 2013 P85

    May 6, 2009
    Ancaster, Canada
    This! I used to run my furnace fan 24/7 but it increased my electricity usage by 50%! (Mine uses around 500W while running)...
  8. TheTalkingMule

    TheTalkingMule Distributed Energy Enthusiast

    Oct 20, 2012
    Philadelphia, PA
    Electric clothes dryer? The wrong unit can use as much power as a central air conditioner.
  9. ItsNotAboutTheMoney

    ItsNotAboutTheMoney Well-Known Member

    Jul 12, 2012
    Think of every W of internal appliance power as a 1W heater.
    - Help your house stay cool.
    - Insulation
    - Shade (e.g. trees)
    - Close curtains/blinds during the day; have curtains/blinds that keep out a lot of light
    - Whiten a dark roof
    - Be efficient with appliances: every Watt of electricity used when it's hot is a Watt your A/C is cooling
    - Solar PV also helps keep heat off your roof, so if you reduce electricity use, then get solar PV you'll also be paid extra in A/C savings
    - Turn off unused appliances and lighting:
    - Be ready to replace old appliances: older appliances are much less efficient, especially refrigeration; be ready to replace them with efficient new models
  10. wk057

    wk057 Senior Tinkerer

    Feb 23, 2014
    Hickory, NC, USA
    You could get the TED Pro Home. I recently installed one, along with their "spyder" system attached to my presumed large load devices, and the extras on circuits I knew were used often (lighting and such). Needed the larger CT for the spyder for the HPWC's 100A circuit, so, keep that in mind if this is something you'll be doing.

    It provides a pretty nice view of everything that is drawing power.
  11. derekt75

    derekt75 Member

    Jul 16, 2012
    San Jose, CA
    My electric bill went up substantially with a baby and nanny in the house during the day.
    I guess the HVAC during the day must be most of that, as they don't watch TV and the house is bright enough to not need lights during the day.
    Speaking of light, yeah, we have a lot of glass in the house. I like it that way. :) The roof is covered in solar panels (14 kW) and pool solar thermal, so tall trees would be counter-productive.
    I'm sure I'd pay less if I ran the pool stuff at night, but then I wouldn't get the solar heat. The solar heating is most effective during the hottest part of the day, and that's when electricity is most expensive.

    I've been using CFLs almost exclusively for some time. LED floods always seemed to be over $30 per light. I just picked up two at Costco last weekend for under $10, though.

    I guess the big things to attack are the pool and the 24/7 stuff.
  12. Kondo

    Kondo Member

    Feb 26, 2014
    Goodyear, Arizona
    I am in Arizona and only run the pool pump from 8 until 9:30 each night and the water is sparkling clear. The pool is 40 X 20 so lots of water. That is a good place to cut back. I heard the rule of thumb is 1 hour for every 10 degrees of temperature and it sounds as if you are there. My water temp is now 88 and I am keeping the same 1.5 hours now for 3 years for all months. Good luck.
  13. Lloyd

    Lloyd Well-Known Member

    Jan 12, 2011
    San Luis Obispo, CA
    Look into getting a separate high effeciency pump for your solar that you run during the day, and do your filtering at night.

Share This Page

  • About Us

    Formed in 2006, Tesla Motors Club (TMC) was the first independent online Tesla community. Today it remains the largest and most dynamic community of Tesla enthusiasts. Learn more.
  • Do you value your experience at TMC? Consider becoming a Supporting Member of Tesla Motors Club. As a thank you for your contribution, you'll get nearly no ads in the Community and Groups sections. Additional perks are available depending on the level of contribution. Please visit the Account Upgrades page for more details.