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Did I just spend $24.89 to save 43 cents a month on the electric bill?


Look what I found at the library last week! It’s the Kill A Watt Electricity Usage Monitor.

This is great because I have been trying to cut down our electricity usage this year. Our electric bill has been trending up over the last few years. Take a look at our daily usage graph.

electricity daily usage saving

The big spike in winter 2011 was due to baby RB40. He was born in the middle of winter and we cranked up the heat after we bought him home. That largest bill was $125 for reference. Previously, we used much less electricity (see 2010) and I would like to get close to that level eventually. Our condo is in a concrete building and it retains heat quite well. The ability to retain heat and our kotatsu table kept our bill low before 2011. I think we can teach Kid RB40 to use the kotatsu table this year and use the heater a bit less.

Go Green

Saving money is one factor, but we would like to live a more sustainable lifestyle and use less energy overall. Last month I purchased a couple of power saving devices from Amazon to help us out. I’ll do a quick review here. All the product links on this page are from Amazon. They have nice product pictures so you can see what these devices look like. Please don’t feel obligated to click on them.

Belkin Conserve Power Switch ( I paid $6.99)

The first one is a simple socket with a switch. When I went to visit my aunt in Australia, the wall sockets in her kitchen has small switches built in. I thought this was a great idea and I have been trying to find something like that in the US ever since.

I plug our hot water dispenser into this switch and turn it off after we make coffee in the morning and go off to work. I have a feeling this hot water dispenser uses a lot of electricity.

Belkin Conserve Socket with Energy Saving Outlet ( I paid $24.89)

This device is intended to be used with your entertainment center. You can plug the TV into the master outlet and when you turn off the TV, it will cut power to 4 controlled outlets. There are 2 outlets that are not controlled and are always on.

Currently, I have the TV plugged in to the master and the DVD player, stereo receiver, and the XBOX in the controlled outlet. In this configuration, I’ll eliminate the vampire power to these devices and save some $$$ in the process.

Electricity usage

We went to story time at the library last week and I spotted the Kill A Watt near the new books section. This was great because now I can find out how much money I’m saving with these devices and how long it will take to break even. I’ve been busy plugging my electronic devices into the Kill A Watt and here are the results.

Device Active Standby
Cellphone charger 2.5 w 0
Laptop  40 w 0
DVD player 10 w 0
Spiral light bulb 25 w 0
Hepa air purifier 19-80 w 0
Stereo Receiver 39 w 2 w
Xbox (original) 70 w 3 w
42’ LCD TV 250 w 0
Hot water dispenser 680 w (boiling) 36 w (keep warm)
Toaster oven
1,550 w 0
Space heater 620 – 1,500 w 0

As I suspected, the hot water dispenser is one of the biggest electricity users we have. The toaster oven is quite a power hog too, but it’s on only for a few minutes per day so overall, it’s not bad. The space heater uses a lot of power too, but I need to figure out how how much power it uses per hour since it cycles on and off. I’ll redo this again when we need to turn on the heater in the winter.

Vampire Power

To me, vampire power doesn’t seem to be  a big factor in our household. The way I have the entertainment center setup, I’ll save 5 Watt hour or about 120 kWh/day at the most (5w x 24 hours.) That’s 3.6 kWh (kilowatt hours) per month. We are paying about 12 cents per kWh so the total savings comes to… drum roll…. 43 cents/month.

I paid $24.89 for the Belkin Conserve Power strip. At this rate it will take about 57 months to get that back. That’s not exactly a great investment.

Active Shut Down

The Belkin Conserve switch on the other hand needs an active hand to flip the switch. I know it’s almost just as easy to pull the plug, but I never do it. With the switch, I can turn it off for about 10 hours every weekdays. The Kill A Watt can find out how much energy a device uses over time. You just plug it in and check several hours later to see how much energy it used.

I plug the hot water heater in over night and got 530 Wh in 13 hours. That’s about 41 W per hour. That’s pretty surprising to me because it tells me the hot water dispenser didn’t spend that much time boiling water. In the previous table, we saw that it took 680 W while boiling water and used 36 W while keeping warm. Anyway, here is a small table to compare the hot water dispenser to our fridge (9.4 cubic feet total capacity.)

Device Hourly kWh
Hot water dispenser About 40.75 Wh
Small refrigerator  About 46.46 Wh

Let’s calculate how much money we would save with the Belkin Conserve switch.

Saving estimate

  • 10 hours per day
  • 20 working days per month
We’ll end up saving about 8.15 kWh per month for a total of 98 cents/month. That’s better than the power strip, but it requires an active role from the owners. I’ll try my best, but I’m sure I won’t remember to hit the switch every day. The payback time is around seven months on this device if I can do this consistently. Flipping the switch is much easier than pulling the plug so perhaps it will work out.

Are they worth it?

I think these power saving devices are worth the price. It will take a long time to get my money back, but our goal is to live more sustainably and leave a smaller energy footprint. Sure, I can just turn off the entertainment center power strip manually. In fact, I tried, but it just didn’t last. I think I can do it for the water heater though because it’s much more visible and within reach on the counter. (Mrs. RB40, our editor, is a bit skeptical.)
Are you doing anything to save electricity? I think the key is to buy energy efficient appliances to begin with. If you have an easy power saving tips, please share it.  
electric save money

We must be doing something right.

Light bulb reference from wiki.answers.com

A 60 watt light bulb uses 60 watts of power in a period of one hour or 60 watts in one minute or 60 watts in one second or 60 watts during any period of time.
How much total energy a 60 watt light bulb “consumes”, which is the amount of electricity that has to be paid-for, is measured in watt•hours (that’s watts times hours). So a 60 watt bulb consumes 60 watt•hours in one hour, or 60 Wh x 24 hr/day = 1440 Wh per day.

That is the same as 1.44 kilowatt•hours (kWh), so, if you look up what your electricity supplier charges for 1 kWh you can figure out how much it would cost you in money. If 1 kWh costs you 25 cents, then leaving a 60 watt light bulb switched on for 24 hours straight would cost you 1.44 kWh x 25¢/kWh = 36 cents.


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Joe started Retire by 40 in 2010 to figure out how to retire early. He spent 16 years working in computer design and enjoyed the technical work immensely. However, he hated the corporate BS. He left his engineering career behind to become a stay-at-home dad/blogger at 38. At Retire by 40, Joe focuses on financial independence, early retirement, investing, saving, and passive income.

For 2018, Joe plans to diversify his passive income by investing in US heartland real estate through RealtyShares. He has 3 rental units in Portland and he believes the local market is getting overpriced.

Joe highly recommends Personal Capital for DIY investors. He logs on to Personal Capital almost daily to check his cash flow and net worth. They have many useful tools that will help every investor analyze their portfolio and plan for retirement.
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{ 37 comments… add one }
  • [email protected]&More October 15, 2012, 7:45 am

    Now that the water wont be kept warm will it spend more time boiling and eliminate the savings? I doubt it but it is a thought…

    • retirebyforty October 15, 2012, 11:21 am

      I will check it out, but I’m pretty sure that unplugging the thing for 8 hours is much better than keeping it on.

  • Kathleen @ Frugal Portland October 15, 2012, 10:45 am

    Silly Joe! You’re not going to have a lot of vampire energy suck since you’re at home during the day.

    • retirebyforty October 15, 2012, 11:20 am

      We don’t watch TV all day.
      The hot water dispenser is mostly for the Mrs. anyway. 🙂

  • Kevin @ Ask For Benefits October 15, 2012, 11:05 am

    Wait ten years or so until baby RB40 becomes a teenager. I have five teenagers who never turn off a light.

    I have been considering installing motion sensor switches so the lights turn themselves off automatically. Also, many of the lights in the bathroom (the place where lights are left on most frequently) have multiple bulbs. The primary kid bathroom has ten bulbs. I started by using lower watt bulbs, and moved to using four that light along with six that burnt out months ago.

    Our electric costs are $.16 kwh. I have been wondering if the investment would be worthwhile. Your kwh calculations on a light bulb were most helpful – thanks!

    • retirebyforty October 15, 2012, 4:09 pm

      Jeez, that’s crazy. I’m not looking forward to the teenage year at all.
      A motion sensor would be great, but you’re not moving much when you’re on the throne right? 😀

  • Laurie Carlson October 15, 2012, 11:35 am

    What I do instead of buying these devices is to FLIP THE SWITCH on the Circuit Breaker Box! I don’t have stairs that lead to it, it’s just in the laundry room off the kitchen, but if it were, it’s more exercise for EVERYONE if they want to use an electrical device. I also use the spiral lightbulbs and any other device that uses less electricity when purchasing one.
    I HATE giving Edison my money!
    Over the last 3 years, this previous one with flipping the circuit board switch, and with the help of manufacturers making better energy saving devices, our bill is using the LEAST amount of electricity we EVER have, without the use of these devices. Whatever works for the many different people and their lifestyles.
    For what our bill is each month, I would be SCARED TO SEE IT NOW had we NOT taken these measures to save! Our average bill from 3 years ago can be LESS by $10 to $100 in the summer with the Air, or the Winter with the furnace.
    The MOST important thing to keep in mind is to keep the heat set at the lowest temperature you can be comfortable at, (wear more clothing) and keep your Air set at a higher cooling setting (wear less clothing!)
    Using ALL of the energy savings available today, and what WE can do to save, it ALL works!
    GREAT article!

    • retirebyforty October 15, 2012, 4:06 pm

      That’s a great idea. We don’t use the AC much and we’ll see what we can do in the heating department this year. Flipping the circuit breaker is a good idea too.

  • jim October 15, 2012, 11:49 am

    I think some people made too much over the vampire power issue. It was never that big of a deal in general.

    And newer appliances are a lot better with power drains when they’re off. Older stuff is worse. I measured my own stuff about 3 years ago. At the time my cell phone chargers were wasting 0.26W while unplugged. Thats not a lot but its senseless to waste it. My older 55″ DLP TV uses 6W in standby and we have a DVD/VHS player that used about 5W in standby. 11W between the two would add up over time. You’re talking $1-2 /month in wasted electricity. Items likeDVRs are the worst cause they are not ever really ‘off’. They can often pull 30W in their ‘off’ status, but since they actually need to be on all the time theres nothing to do about that.

    The Kill-a-Watt doesn’t have enough accuracy to measure the very small Watt usage of some things on standby. You might keep the item plugged in for 24 hours and see if the Watts add up over time. So the metermight show 0.00 but in fact its using 0.002 or something. Of course its still negligible but some items may have a very small draw rather than 0.

    • retirebyforty October 15, 2012, 4:13 pm

      I think you are right. From what I found during my research, the older devices had much higher standby drain. A new TV uses less 1-2 W on standby.
      I didn’t see anything overnight on the Kill A Watt because it only shows kilowatt and 2 decimals.

  • Abigail October 15, 2012, 12:20 pm

    I hadn’t heard of the power conserving plugs, but they could do us a world of good. We have gaming consoles, not just a TV. So we’d be saving more than just a TV vampire drain.

    I do think people make too much of a fuss over vampire drain. But, as you pointed out, it’s better for the environment. And here in AZ where electricity triples in price in the summer (because, what, are we going to NOT use the A/C?) it could save a pretty penny. Maybe just a few of them. But they’re pretty so…

  • krantcents October 15, 2012, 3:01 pm

    I Changed all our lighting to CFLs. I also bought a new refrigerator which should lower our bill. I have really nothing to complain about because my utilities run about $70 a month average.

  • Justin October 15, 2012, 5:27 pm

    I wish my library had one of those kill a watt meters.
    You could save money by unplugging the device every time, but then there is possibility that you could damage the cord from pulling it out too many times (I’m thinking years here). If that were the case then the switch pays for itself by the fact that you wouldn’t have to replace a cord.
    Also, for the water warmer you could purchase an electric tea kettle. They warm up so fast and you only need to turn it on. They turn off automatically once the water comes to a boil, it seems to be less than a min, though never timed mine.

    • retirebyforty October 16, 2012, 5:35 pm

      I tried pulling the cord, but it’s just not convenient and I didn’t stick with it. The wall plug switch made it a lot easier. I think we’ll try the electric kettle after the current hot water dispenser bites the dust. 🙂

  • mbhunter October 15, 2012, 11:03 pm

    The coup de grace was the bulb miser. It was a temperature-compensating thermistor developed by a company that went out of business. They sold for $2 apiece in the 80s, and they keep (now contraband) incandescent bulbs burning longer.

    • retirebyforty October 16, 2012, 5:36 pm

      I never heard of the bulb miser. It’s a pretty interesting device.

    • jim October 17, 2012, 11:17 am

      Bulb miser seems like a good idea. The idea was to put a thermister between the bulb and the socket to help keep the bulbs from burning out when you turn them on. It claimed to increase bulb life an average of 300%.
      The bulb miser reduced the light output of the bulbs and took 30-60 seconds for the bulb to get to full power. $2 in 1980 is $5.60 today. They’d work best for lights you turn on/off more frequently. Would actually have a negative impact for a bulb that you left on 100% of the time. But of course CFL’s would be better economically and I suspect CFL’s killed bulb misers.

  • Cherleen @ My Personal Finance Journey October 16, 2012, 1:44 am

    I have simple rules at home to save on electricity — unplug all unused appliances and turn off the light if there is no one inside the room. It is a good thing that the children are in school most part of the day so it is only the fridge, TV, and computer that are turned on during the day.

    • Manette @ Barbara Friedberg Personal Finance October 16, 2012, 1:56 am

      I agree. A simple act of turning off the light and unplugging unused appliances would definitely reduce your electricity bill. We have also replaced our bulbs with CFLs. However, it is inevitable that electricity usage increases during winter. The heater uses up a lot of electricity no matter how we lessen our usage.

      • JoeTaxpayer October 20, 2012, 5:49 am

        Winter isn’t half as bad as summer for us. Heating is actually far cheaper than cooling, so for those of us who like 68F as their comfortable temperature, the summer is the killer, but winter, well, a bit of cooking, and the extra heat generated by our gadgets, and you’re halfway there.

        • retirebyforty October 20, 2012, 8:10 am

          Really? You must live in a more temperate part of the country. We keep our thermostat at 64 and heating still cost us quite a bit.

    • retirebyforty October 16, 2012, 5:37 pm

      It’s great that you can do it consistently. I’m too lazy to go around unplugging everything. 🙁

  • Mike October 16, 2012, 5:00 am

    At least you are willing to be able to experiment with ways to reduce your costs down further. I’m still trying to figure out all those little things myself…..

  • Will (Wise Bread) October 16, 2012, 11:34 am

    I love the fact that instead of just trusting in the advertising copy, you ran your own test and recorded your own results. I submitted this to the /r/frugal and /r/environemtn subreddits. I think our fellow geeks would enjoy this methodical approach. =)

    • retirebyforty October 16, 2012, 5:38 pm

      Thanks for the submission. It was a lot of fun to find out how much power each appliance drains.

  • vanvalks October 16, 2012, 1:19 pm

    We too have a young one in our home and his room is one of the coldest in the house so last winter we purchased a 1500 watt electric heater to help keep his room warmer at night. Soon after I noticed our utility bill shoot up. I purchased a kill-a-watt meter and found out that running the heater at night (even though it turns on and off periodically throughout the night) costs approximately $25 to $30 per month! At that price I almost think it would be cheaper to keep our whole house warmer at night, but have yet to test that theory.

    The kill-a-watt was a great purchase as I’ve plugged it into several other things since then and have been somewhat surprised at which things consume a lot of electricity and which do not. Well worth the money!

  • JoeTaxpayer October 17, 2012, 12:55 pm

    I have a kill-a-watt and discovered an old Mac computer I left on was costing $16/mo. It’s off now and I told my wife to put the family room computer to sleep when she walks away from it. ‘Sleep’ is a tiny fraction of the power compared to ‘on’.

    A 5 year payback for a long life item is great. If I spend $1000 and it saves me $200/yr, after 10 years I’ve saved $2000. Even if it dies then, it’s a decent return.

    • retirebyforty October 17, 2012, 5:16 pm

      Wow, that’s a lot of power. I guess the old computers weren’t very efficient.

  • Lisa @ Cents To Save October 18, 2012, 9:26 am

    We have a timer on our water heater. It is set to be on for three hours in the am and three hours in the pm. This fits our schedule and saves money. Just a note, an electrician is needed to install the timer, but our sons are electricians so the cost was dinner at mom’s. 🙂

    • retirebyforty October 18, 2012, 12:36 pm

      This is a great idea. I think we’ll try a tankless water heater when our current one goes.

  • Lisa @ Cents To Save October 18, 2012, 7:58 pm

    We were looking at a tankless water heater, but at the time it was a bit too expensive.

  • 101 Centavos October 22, 2012, 5:57 pm

    I remember hearing this quote on a random podcast, on having an energy-conservation policy at home “It’s called: turn out the freaking lights!!”. Except that it was the other f-word. Much more dramatic.

  • Jonathan October 25, 2012, 8:13 am

    “I paid $24.89 for the Belkin Conserve Power strip. At this rate it will take about 57 months to get that back. That’s not exactly a great investment.”

    You’re looking at it wrong. What you actually did was pay $24.89 for an infinite series of cash flows of 43 cents per month (it doesn’t stop after 57 months). If you plug that into a financial calculator, you’ll see that the return on your investment is 20.7%. Now tell me that you wouldn’t take that any day of the week! If you similarly had the opportunity to invest $24,890 in return for $430 a month payback forever, you’d probably think of it a little differently!

    • retirebyforty October 25, 2012, 8:41 am

      If it works forever, that would be great! This thing is pretty new though and I hope it last at least 5 years for me to get my money back. 🙂
      The annual ROI is 1.7%. I guess that’s not bad, but you can find solid dividend stocks that pay more, right?

      • JoeTaxpayer January 10, 2013, 3:31 pm

        The 1.7% is per month. 20.7% per year.
        If I could get 15% per year guaranteed, I’d be retired right now. (Actually even 8% might do it)

        • retirebyforty January 10, 2013, 10:30 pm

          Don’t forget that someday the gadget will break and the principle + future interest will be gone at that point. 🙂

  • solar panels Los Angeles December 8, 2012, 6:45 am

    I would like to own a device like that too.

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