If you want to know how to save electricity, you have to start by measuring. Once you know how much electricity you use, and especially how much electricity each of your lights, appliances, and other items uses, you’ll quickly find ways to reduce electricity use in your home.

I should know. Our family went from using about a third the electricity of the average Ontario family of four, to cutting our electricity to just one sixth of the average. By knowing where we used electricity, we figured out how to save electricity beyond what most people would think possible.

This all started in 2006, when we looked into installing a home solar electric system. A solar engineer did a site assessment and checked our energy bills. Then he told us he would not install a solar electric system until we had found ways to reduce electricity use in our home by half, because, he said, it’s much cheaper to cut waste up front, than to add more solar panels to power the waste. He said we should try to go from 11 kilowatt hours per day (kwh/day) to 6 kwh/day.

This amazed me – I knew we used much less electricity than our neighbors. Could we really cut back by another 50%?

Is 6 kwh/day a realistic goal for a family of 4?

The solar engineer assured us we would easily figure out how to save electricity enough to bring us down to 6 kwh/day. The secret, he said, was to measure electricity usage rigorously. He sold us a Kill A Watt meter, which lets you measure the power consumption of electrical devices, such as watts used for a light, toaster, or fan, or kilowatt hours used over time, such as for a fridge or washing machine.

Measure for measure


We walked through the house and made a list of every light, appliance, or other electrical device. The furnace fan, the central AC, window fans, kitchen and bathroom fans. Computer and peripherals. TV, DVD and VCR. Then we measured or estimated the electricity use of each item.

For lights, we read the bulb wattage, and estimated the hours each light was used per day. For electronics, plug-in fans, and other occasional-use devices, we measured the wattage through the Kill A Watt meter, and estimated how long much device was used each day. For the fridge and freezer, we measured kwh used over a period of at least 3 days, then computed the kwh per 24 hour period. For the washer and dryer, we measured kwh per load, and estimated number of loads per year. For yearly figures, we calculated kwh per year using the formula Watts x Hours/day x Days/year / 1000. Here’s a sample of entries in the spreadsheet we created:

Room Item Watts Mins/day Hours/day Days/year Kwh/y
Bathroom Fan 180 15 0.25 330 14.9
Bathroom Washer 300 90 1.50 104 46.8
Office Modem 7 24.00 365 61.3
Office Router 9.5 24.00 365 83.2
Rec room Stair lights 100 60 1.00 330 33.0
Rec room Dehumidifier 300 0 0.00 20 0.0
Workroom Furnace high 500 1.00 150 75.0
Dining rm Stained Glass lt 60 90 1.50 200 18.0
Back porch Lights 300 10 0.17 30 1.5
Kitchen Bread maker 300 60 1.00 150 45.0
Kitchen Fridge 100 15.00 365 547.5
Kitchen Lights 165 150 2.50 330 136.1

Once we had these measurements and estimates, we calculated our total estimated electricity use for a year. Amazingly, when we checked our electricity bills, the estimate almost exactly matched actual consumption.

So if you want the first secret on how to save electricity, it’s this:

How to save electricity, tip #1

Measure your electricity use carefully and in detail.

To really save electricity, start by measuring everything. Buy a Kill A Watt meter or similar device. We paid a whopping $60 for ours three years ago; I’m sure it’s paid for itself several times over. And they sell for as little as $25 now. Make a list of every electricity consuming device in your home, and measure or guesstimate its power use. Figure out where the big energy hogs are, and where you’re using electricity that is not really doing you any good. From there, plan how to save electricity.

Our next step was to tackle two things: how to save electricity on the electricity hogs, and how to cut back on smaller energy users that provided no benefit.

The top energy users in terms of kwh used per year were:

  • A wine cellar with a very inefficient cooling apparatus (558 kwh/year)
  • A chest freezer (360 kwh/year) and fridge (548 kwh/year)
  • Lighting throughout the house. The kitchen alone used around 200 kwh/year.

Energy users that provided little or no benefit included:

  • The office cable modem, router, and printer, which used 180 kwh/year, even though the computer was only on a couple of hours a day and the printer was used perhaps two minutes per day.
  • The coffee maker, breadmaker, DVD player, VCR player, and television, each of which was plugged in 24×7 but only used for a few minutes a day or a few hours a week. Each of these devices (at least the versions we own) draws 2 to 10 watts, sometimes more, of continuous power – so we were using about 15 watts constantly, or 130 kwh/year, when most of the time we had no use for the devices.

Our first cut was the wine cellar. I had built the cellar because I fancied myself a wine connoisseur, but the cooling unit was very inefficient. We shut it down, enjoyed a few bottles of well aged French wine, and just used the naturally cool cellar air to store fewer, more modest wines. This brings me to one of the key things I learned about how to save electricity:

How to save electricity, tip#2

Challenge yourself to redefine necessities as luxuries, and give them up.

I didn’t really need that wine cellar, except as a way to boost my own ego. My palate is actually pretty crude, and using the energy equivalent of 560 pounds of coal per year to keep my wines cool was not an ecologically sustainable decision. (Other energy-intensive things that you might think of as necessities but that might really be luxuries include air conditioning, basement beer fridges, and any appliance our grandparents got by perfectly well without.)

Even though our refrigerator was ENERGY STAR rated, it used more electricity than just about anything else in our house. A simple check of the fridge and freezer temperature revealed that someone had accidentally turned the freezer thermostat down much too far, so the freezer was running continuously, lowering the compartment temperature to -25C, well below the -15C required for short- term storage. We now measure refrigerator temperature regularly, to make sure we’re not unknowingly using more energy than needed to keep our food cool.

Freezer burn

chest freezer full of tomatoes

Maybe these should be canned?
Photo by Jonny Hunter, via FLICKR

Next we shut down the freezer. It was only half full, and half of its contents was of the ‘freeze and forget’ variety: leftovers or old ice cream or summer fruits and vegetables you don’t want to deal with now, so you freeze them and plan to use them later. But you forget, or can’t be bothered, or don’t want to think about those cubes of frozen squash, so it stays in the freezer until spring cleaning time.

Now our freezer is a handy storage bin for Christmas ornaments and wrapping paper, and it uses 0 kwh/year. If we ever need overflow freezer space, we can start it up again while it’s needed. But it doesn’t make sense to use 360 kwh per year on a freezer that is mostly storing freezer burn. Which brings me to another key thing we learned about how to save electricity:

How to save electricity, tip #3

Challenge your own ideas about what you consider necessary.

Actually, this tip is pretty close to How to save electricity tip #2, except that in tip #2, I suggest that you redefine a necessity as a luxury so you can give it up; here I just mean that you should look for things that you do because you think they’re necessary, when they are in fact optional. Some of them might even be pointless!

Do you really need that light on?

Lighting was another big area to cut. Here are two key points on how to save electricity on lighting:

  • Use lights less. Turn them off when you’re not in a room. Remove some bulbs from ceiling fixtures, or put them on a dimmer switch, if you don’t need the full light level the fixture provides. Turn off the kitchen lights if you’re eating dinner in the breakfast nook or dining room. Rely more on natural daylight.
  • Use more energy efficient lights, especially where the lights are on for many hours each day. Upgrade incandescent light bulbs to compact fluorescent lights. Upgrade halogen pot lights to LED lights. We got rid of our incandescent Christmas lights and bought LED Christmas lights instead. We had already installed CFLs in some fixtures; we installed many more.

Do you really need that thing plugged in all the time?

The items that used small amounts of energy while providing no benefit were easy to fix. We put the computer and peripherals on a power supply bar, so that we only used them when the computer was on. You might not think that 5 or 10 watts matters, but when you’ve got half a dozen peripherals each using 5 to 10 watts that are plugged in continuously, with each one using 40-80 kwh per year, that can add up to 480 kwh per year altogether. This is a big part of how to save electricity: don’t leave anything plugged in that draws power, unless you actually need it to be drawing power.

In our case, computer peripherals left on continuously were using 180 kwh per year; putting them on a power supply bar cut that to about 1/12 the original, or 15 kwh/year. Unplugging the VCR, TV, coffee maker (with its 2-watt LED clock) and breadmaker helped as well. All told we cut our “phantom load” or “vampire load”, as this continuous and pointless drain of electricity is called, by about 315 kwh per year.

You may have devices drawing a steady, continual current that are not providing you with any benefit other than the pleasure of a TV screen that goes on instantly (cost: up to 440 kwh/year), or the convenience of a flashing DVD player clock (cost: up to 88 kwh/year). Which brings me to another important tip:

How to save electricity, tip #4

Unplug everything that isn’t immediately needed

There are some things that don’t draw any electricity when they’re shut off, such as most lights, blenders, toasters, fans, and so on. However:

  • For anything that uses an AC adapter, the adapter may be consuming power, even when the device plugged in is already fully charged, or is not being used, or is not even attached to the adapter. This includes laptops, cell phones, computer peripherals and the like. Some AC adapters use little or no power when not connected: our ThinkPad power adapter uses only 0.2 watts when plugged in but not connected to the laptop. But if plugged into the laptop, it uses quite a bit more than that even when the battery is fully charged. If in doubt, measure with your Kill A Watt meter or equivalent.
  • Anything that can be turned on by remote control – a TV, DVD player, stereo, ceiling fan – is probably using some energy waiting for the signal to go on. It may be only 2-3 watts, or it could be up to 10 watts. Either way, it adds up – for every watt of continuous power you have, you use nearly 9 kwh/year of extra power.
  • Anything with a digital clock must be drawing a small amount of power to keep the clock running. This may only be half a watt but more often it’s in the 1-3 watt range (9-27 kwh/year).
  • Instant-on televisions use electricity continually to keep the screen warmed up so it can turn on instantly on demand. While an instant-on screen is convenient, can you justify 50 watts of continuous power draw for that convenience? That’s 438 kwh/year. Remember How to save electricity tip #2? Here it is again: Challenge yourself to redefine necessities as luxuries, and give them up.
  • Central furnaces and air conditioners draw a small amount of power year round if their circuit breakers are left on – even at times of the year when there’s no need for heat or cold air. This power is to keep the thermostat connection to the furnace or air conditioner active, and can be several watts of continuous power, or up to 60 kwh/year. During times when you don’t use heat or AC, switch the furnace and AC circuit breakers off.
  • Some personal computers are made with a cheap power switch that instead of cutting power supply to the inside of the box, cuts power from the power supply inside the box to the other parts of the PC. This means you may be powering the power supply continuously, even if the PC is shut down. The best way to get around this is to buy an ENERGY STAR rated computer, or make sure your PC is on a power bar that is kept off when you aren’t using the PC. If you own a Kill A Watt meter you can do a measurement on the computer when it’s switched off but still connected to a live power supply, to see if it draws any current.

As we tackled the big items and the many small items that draw power continuously, our energy use dropped from about 11 kwh/day down to under 8 kwh/day. That’s about a quarter what the typical Ontario family of four uses, according to the last numbers I checked.

Continuous improvement

As you cut back on your biggest energy users, some smaller energy users bubble to the top.

For example, our stove didn’t use that much energy – just over 5% of our total electricity bill was for stove top and oven cooking, by my estimate. But once we’d cut some of the big hitters – 558 kwh/year for the wine cellar, 360 for the freezer, 270 for phantom loads, and 40 kwh/year off lighting costs, we’d reduced our electricity consumption by 1,228 kwh/year. That means that each remaining item would now make up a larger percentage of the remaining energy consumption.

So the stove and oven used 195 kwh/year, which was about 5% of the total energy use at the outset, but after cuts elsewhere that rose to 7.5%. So we changed our cooking habits. We switched to a crock pot for some meals instead of an oven, cut back on baking or baked several items at once instead of through the week, and made sure to measure the amount of water we boiled for tea or for a cooked dish. No more opening the oven door every five minutes to peak in on the baking.

This brings me to yet another tip on how to save electricity:

How to save electricity, tip #5

Keep raising the bar. You can always cut
your use further.

By raising the bar, I mean setting more ambitious savings goals. Don’t tell yourself the job is done when you’ve reached a good level of savings. Keep pushing the limit. That’s how to save electricity in a big way. You’d be amazed at how little electricity it takes to live a happy, fulfilling life. Keep measuring electricity use. Do daily meter readings to see if your use is falling as expected, or holding steady, or starting to rise.

Sometimes how to save electricity is not even a question of raising the bar, but just making sure the bar stays high. After our efforts on how to save electricity the first three months after the solar engineer’s visit, we got our consumption down to 6 kwh/day. But then our use started to rise again, as we stopped focusing on how much electricity we used. We soon drifted back up to 8 kwh/day. Of course, part of that may have been that the zeal with which we first approached the project soon faded. We also switched to a green electricity supplier, so we may have felt less guilty about a small amount of waste.

But I’d love to get us back down to that 6 kwh/day level for the long term. Especially since, if we can figure out how to save electricity at that level continuously, we can call up our solar engineer again, and ask him for a quote!

Why save electricity?

The obvious first reason is money. You’ll save a pile of money if you can cut your electricity use to half or a third of what it was before.

Another reason, that in mind is actually more important, is that you’ll be able to use your savings to switch to a green electricity supplier, as we did, or to buying “Green Tags”, which are certificates that allow a green electricity producer (wind farm for instance) to produce clean power and sell it to the grid at the regular dirty price, while covering their higher capital costs with your green tag.

A third key reason is to cut your ecological footprint. Even if your own electricity doesn’t come from a dirty source like coal, or a fossil-fuel-consuming source like natural gas, you’ll still make the air cleaner and the concentration of greenhouse gases lower if you reduce your electricity usage, because the electrical grid is a melting pot of electricity sources and end uses.

Where do you go from here?

If you’re ready to get serious on how to save electricity, start with an electricity usage monitor. See the following page for more details:

If you think that a particular household appliance such as a fridge, freezer, stove, washer, or dryer is a big part of your problem, look for that appliance on the following page, and follow the link to tips on how to make the appliance more energy efficient, or how to select a new, more energy efficient model if it’s time to replace your old one.

If you want to cut your air conditioning costs, you can go three ways: cut your reliance on air conditioning; get more out of your current air conditioner; and find the most energy efficient new air conditioners available. Use the links on the following page:

You can work on saving energy with lighting by looking at newer lighting technologies such as compact fluorescent and LED lights. It’s important to figure out whether switching to a newer technology will actually pay back your up-front investment; I provide calculators for both LED savings and CFL savings. It’s all linked from this page:

There are devices that can save you electricity in a number of ways. There are also devices marketed by some websites and businesses that claim to substantially cut your home power use, or refrigerator use, but don’t really help much if at all. I describe many devices, both helpful and questionable, on this page:

2 replies
  1. Tim
    Tim says:

    In my home the biggest electricity usage goes to my water heater. I noticed you did not mention a water heater in your analysis. Do you have one, and if not how do you get hot water?

    Reply
    • Robin
      Robin says:

      I have a natural gas water heater with tank, so it is not factored into my analysis of how to save electricity.

      The challenge with an electric water heater is determining how much energy it uses, when there is no way to meter its use directly.

      If you use a whole house power monitor you could try to figure out electric water heater power consumption, assuming you can figure out your incoming water temperature, hot water temperature, and typical consumption per day.

      A web page I often use is this energy calculator. It’s a bit overwhelming, but if you search on the page for “energy storage systems” you’ll find a table where you can enter, in the section labeled Thermal on the left, second line in that section, the amount of water you use each day, in gallons, and the amount of temperature increase. So for example, suppose you estimate you use 30 gallons of hot water a day, the incoming temperature is 40F, and the outgoing temperature is 120F, you would enter 30 in the ‘heating a ___ gallon tank’ field, and 80 (120-40) in the ‘by ___ degrees F’ field. Any time you enter any value in the calculator, all other values magically update to show the amount of energy involved in each possible format. If you scroll back up to the ‘Energy (used or delivered)’ section a screen or two above, you’ll see that that works out to 5.765 kilowatt hours. That tells you how much energy it takes to heat the water.

      What it doesn’t tell you is how much of that energy will be lost to heat leakage in the hot water tank over time. That leakage depends mainly on the amount and quality of insulation around the electric hot water tank. You can buy electric water heater blankets of various prices/sizes/insulation capacities, and this will at least help reduce heat losses.

      Reply

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