I now know that it costs us about $0.50 per hour, and $2.00 per day, to watch TV at my house. I also know that it costs about $0.30 per day to keep my food at a good temperature. Why is this important? This helps me to understand where I can make investments in time and money to most efficiently to save me both money and energy in the future.
There is very little I can do to reduce my refrigeration costs. I can buy a new refrigerator that is maybe 10% or even 20% more efficient, but a 20% savings would save me $0.06 per day or $21 per year. If a new refrigerator costs $2000, I would not see any of my money back for 100 years. I can, however, always watch less TV, or find a cheaper cable provider, or even buy a gadget to reduce the standby load when the TV is turned off.
As I think I've mentioned before, I play around with computers for a living and work out of an office in my home — my daily commute is amazing. For many years now I have done my work on a Sony Vaio desktop computer with a 19" LCD monitor. It was a state-of-the art system three years ago and is still a nice system today. On average, I spent eight hours a day on that computer until recently.
Computers are a little like refrigerators, in that you have to measure power usage over a broad period of time. When turned on but not doing anything, my desktop computer uses 100 watts, but when the processor is working and the disk drive is whirring, it uses 170 watts. When measured over the course of several days, however, my desktop computer uses on average 160 watts per hour. The 19" monitor uses another 35 watts per hour, plus another five or so watts for the router and modem, so the basic per-hour power usage for my desktop computer is 200 watts per hour. Multiply that by our average cost per kWh of $0.10 and my desktop computer costs $0.02 per hour to run, or $0.16 per day, or $5 per month, or an annual cost of
That's a pretty good value, particularly when you compare it to the $500 we spend every year for high-speed access to the internet.
I recently switched from using my desktop to this HP laptop, however, which uses 20 watts per hour or 1/10 as much power. My cost per hour for the electricity to run this laptop is one-fifth of a cent and my annual cost is
It's important to focus your energy-saving efforts in areas that make sense. I now have a computer I can take with me, that also saves me about $50 a year on my utility bills.
What does it cost for computing at your house?
Knowing what it costs to do something like, for instance, refrigerating your food, helps you to understand what opportunities you may have to save energy — and money — when doing that. You may have seen some of these energy-saving tips here at Energy Watcher:
- Keep your refrigerator at 38°F.
- Keep your refrigerator freezer at 5°F.
- Keep your chest freezer at 0°F
- Vacuum your refrigerator coils once a year.
- Shut that refrigerator door! (In fact, I have recently determined that just opening the refrigerator door causes the temperature inside to go up by one degree, and leaving it open for 30 seconds causes the temperature inside to go up by four degrees.)
In order to tell just how much energy we save when we unplug the garage refrigerator, we first have to know how much energy the refrigerator uses when it is plugged in. To do this, we turn once again to our trusty Kill-A-Watt. Since refrigerators cycle on and off based on the temperature inside, we need to use the feature that counts total power consumed over a period of time. So what I did is plug the Kill-A-Watt into the wall, plug the refrigerator into the Kill-A-Watt, press the red button, wait for 24 hours, and then press the red button again and read the total power consumed. Please note that I did not unplug the refrigerator first — one of the things I don't like about the Kill-A-Watt is that it loses whatever your reading was as soon as you unplug it.
Unlike some other appliances, it doesn't make sense to measure power consumption for a refrigerator in units of anything less than one day. If the kids are home that day, power consumption is going to be higher due to the way they leave the door open. For a true test, I really should leave the Kill-A-Watt hooked up for a week or even a month, but I think that one day's measurement is enough for this post.
So here's the numbers: Our 18-cubic-foot garage refrigerator uses 1.1 kWh per day when it's plugged in. We keep it plugged in about six months out of the year, or about 180 days. Our average cost per kWh is $0.10, so our cost per day is $0.11 (1.1 kWh/day x $0.10/kWh) and our cost per year for the garage refrigerator is
and turning the garage refrigerator off for half the year saves us about $20 per year.
I did mention that we have a refrigerator in the kitchen as well. Our 25-cubic foot kitchen refrigerator is in use all year long, has its doors opened much more often than the garage refrigerator, and uses 2.1 kWh per day. Our cost per day is therefore $0.21 and our cost per year for the kitchen refrigerator is
What does it cost to keep your food cold at your house?
Put your Christmas lights, inside and out, on a digital timer to save money on electricity over the holidays.
If possible, get yourself LED Christmas lights. They use 10% as much electricity as old-fashioned Christmas lights, and last 10 times as long as well.
Like all good energy watchers, we like to know what things cost, especially those little things that we all take for granted. For example, what does it actually cost to watch TV? To start with, everyone has different equipment and watches TV for different lengths of time, so we cannot make any blanket statements about TV watching. In other words, your mileage may vary.
I can tell you, however, what happens at our house. We enjoy our 52" high-definition LCD TV enormously — it's almost like being at the cinema. We have digital cable and watch about four hours of TV per day, on average. We mostly watch shows that have been recorded on our DVR but sometimes we enjoy a DVD.
The number that most people have trouble with is how much electricity is being used. To figure this out, I plugged the TV, cable, and DVD player into a plug strip and then plugged that into my Kill-A-Watt. With everything turned off, first of all, I found out that my TV draws about 75 watts of power — please note, that's with everything turned off! With everything turned on, I discovered that my TV draws about 350 watts.
Four hours of TV watching, then, uses about 1.4 kWh of power (4 hours x 350 watts = 1440 watts = 1.4 kWh). My average cost per kWh here in Atlanta is $0.10, so I spend about $0.14 per day for electricity to watch TV — an excellent value! Unfortunately, we are also using 75 watts per hour for the other 20 hours in each day, which adds up to 1.5 kWh of power (20 hours x 75 watts = 1500 watts = 1.5 kWh), or $0.15. Taken together, our cost to power the TV is about $0.29 per day, or about $9.00 per month.
We have digital cable without any premium channels, so our cable bills is about $50 each month. Our cost per month for TV is therefore about $60 ($50 + $9) and our cost per year for TV is about
not counting DVD rentals. Obviously, I'm rounding off these numbers for convenience.
What does it cost to watch TV at your house?
Christmas is right around the corner so if you are looking for tips for gifts for the energy saver in your life I have a few suggestions:
Kill A Watt from P3 International
I cannot recommend this tool enough! The Kill-A-Watt helps you to really understand just how much power your appliances are using, and you really cannot get serious about energy conservation until you understand just how much power you are using.
Waterproof Digital Thermometer from Thermoworks
I've been talking about digital thermometers a lot lately, mostly because this is my latest toy. Similar to the Kill-A-Watt, a digital thermometer helps you to understand what the temperatures around you really are before you start working on how to increase or decrease them.
Smart Strip LCG3 from Smart Strip
I don't have one of these yet, but I am hopeful. Santa? The basic idea is that you can control the power that many appliances continue to use when they are turned off. This vampire electricity usage can really add up — I have calculated that it is costing me about $5 per month for my TV.
Home Energy Audit Kit from Henkel
I have looked up what an infrared thermographic imager costs — between $5000 and $15000. This is an inexpensive alternative. This handy toy doesn't give you the cool false-color image that a thermographic imager does, but will help you to find the cold spots around your house.
Using my handy-dandy new waterproof, dishwasher-safe digital thermometer, I was able to figure out just how hot my dishwasher gets. Various experts say that your dishwasher should get up to 140°F in order to properly sanitize your dishes — and I can tell you from my early days washing dishes in restaurants that commercial dishwashers get up to at least 150°F. The particular thermometer I use has a min/max feature on it that is very, very useful for this sort of project. What I did is turn it on and then run it through the dishwasher in the top rack as part of a normal load. After the load finished, I took the thermometer out and pressed the min/max button. The first time it is pressed, it reports the low temperature since the last time the thermometer was turned on — and the second time, it reports the high temperature, which was 166°F in this case.
Since I had previously set my hot water heater to 120°F, I can tell that my dishwasher has its own hot water heater designed to get the water hot enough to more than properly sanitize the dishes. I may in fact need to dig out the dishwasher manual and figure out if there is a way to turn the temperature down slightly, since there's no need to get the water quite that hot.
As long I was using up the hot water, I decided to see just how hot the hot water was at the tap. Checking the faucet closest to the hot water heater, I found that the hot water was 113°F, slighly cooler than I expected. A quick check downstairs in the basement confirmed that the hot water pipe runs through the un-heated — but now insulated — crawlspace under the insulation. I now know what my next home-improvement project is going to be — I am going to insulate that hot water pipe. Various experts say that it is normal for hot water temperatures to fall off as much as 15°F between the hot water heater and the faucet farthest away from the heater, but our kitchen sink is about 10 feet away from the hot water heater and a seven degree drop is just unacceptable.
Humid air makes you feel warmer than dry air — that's why Florida feels hotter than Arizona when the temperature is the same in both places. In winter, house plants or an aquarium will help your home feel warmer than it really is, so you can turn down the thermostat — and in summer, they will make your air conditioner work harder as well, so this is a double-edged tip.
Another essential tool in the arsenal of any dedicated energy watcher is a waterproof digital thermometer. Our civilization consumes energy for three reasons:
- Moving things from one place to another
- Lighting up the darkness
- Raising and lowering the temperature
Is your programmable thermostat accurate? Mine isn't:
If, like mine, your thermostat reports that it is 68°F in your house when it is really 70°F, then you are spending about 10% more on your heating bill than you need to. My heating bill was about $200 last month — lowering the thermostat to a true 68°F should save me about $20 a month.
Most people keep their refrigerators at about 34°F — any colder and the milk will freeze. But does the refrigerator need to be that cold? Refrigeration accounts for about 15% of energy usage in most homes, so anything we can do to improve that will pay for itself quickly. The simplest way to save money on your refrigeration is to raise the thermostat. Your food will keep just fine when the refrigerator is set between 35° and 38°F.
Just opening the refrigerator door causes the temperature inside to climb by 1°F — we really do have the refrigerator temperature set properly.
When looking for a digital thermometer, always look for one that is waterproof and has a wide temperature range. My particular model is not safe for the oven but is safe for the dishwasher, and has a min/max feature that will let me test just how hot the water in the dishwasher will get — for a future post.
It doesn't make a difference what temperature a room is, it's always room temperature. - Steven Wright
Our friend Birney Summer at Energy Boomer recently published a wonderful list of no-cost winter energy saving tips for seniors. Since I am not a senior — yet — I didn't really pay attention.
And then I realized that this was not just a list for seniors, but a list for everyone:
- Create a warm room where you spend most of your time and turn down the heat everywhere else.
- Put your favorite chair in the warmest spot in the room.
- Pre-heat your bed with an electric blanket. (Try using a timer.)
- Reverse the rotation on your ceiling fan to push warm air down into the living area. (Run it on the slowest speed so you don’t feel a draft.)
- Wear layers inside to trap warmth in air pockets between layers.
- Wear warm clothes to bed, too. (It's OK to wear socks to bed.)
- Keep throw blankets near your favorite chair to drape across your legs to stay warm.
- Wear slippers! (Look for non-skid soles to help prevent falls.)
- Your head can be a significant source of heat loss, so wear a hat inside, too.
- Keep curtains open on the south side of the house during the day to let the sun shine in.
- Block drafts blowing into your home through mail slots and under doors.
- Close the damper on your fireplace when you aren't using it.
- If you have an attached garage, keep your garage door closed.
- Hot meals and beverages provide both warmth and energy during the cold winter months.
- Go south for the winter. (Turn down the thermostat while you're gone.)
Getting at $289 utility bill sucks. It's not a record — hopefully our record $476 bill from August 2007 will stay in a class by itself. As predicted, November in Atlanta was cold, and I expect December to be colder.
Here's the thing, though. As documented in this blog, we have done several energy-saving projects around our house in the past 18 months — more insulation, more efficient lighting, less water usage. As you would assume, our utility bills, compared to the same month last year, have trended downward. When there is a discrepancy, it can be explained. So why was our natural gas usage up 50% over November last year when the number of heating degree days (HDD) this November was only up 25%?
Our water usage is up slightly over November last year, but only slightly, so we cannot blame this on hot showers. We have programmable thermostats, of course, and they are set at 65°F except during the hours of 6am-8am and 6pm-10pm, when they are set at 68°F. The whole family wears sweaters and I have taken to wearing a hat around the house — have I ever mentioned that I'm bald?
So I have to ask what else has changed in our house since last November Right now this is only a theory, but it's the only theory I have: Our middle daughter started driving her own car, which she parks on the driveway. Instead of leaving the house every morning through the front door, she goes out through the garage — and leaves the garage door open when she leaves.
We are going to try an experiment and see if closing the garage doors will make a significant difference in our heating bill in December — and, if I can find the time, install some more insulation in the basement.
November 2008 Data
Electricity, in kWh
Cost / Unit
Gas, in Therms
Cost / Unit
Water, in CCF
Cost / Unit
Has anyone noticed that it is colder so far this heating season? My recent gas bill at home said the weather is 5 degrees colder than the same month last year.
Weather history data, for this part of Ohio, shows October and November were both colder than last year and about 10% colder than normal. The forecast for the first couple of weeks for December indicate it will be colder than normal too.
I’ve been researching trying to find out why the weather is so much colder this season. One possible explanation is that solar activity is at the low point in its eleven-year cycle.
The energy we receive from the sun is the source of most of our energy here on planet earth.
The sun is certainly the driving force for our weather. The heating and cooling of our globe as the earth rotates drives the winds and moisture movement in the air.
This year, there have been more than 200 days when there were no visible sunspots. The last time that many days without sunspots occurred was in 1954. Yup, 54 years ago, in 1954, there were 241 days without sunspots. There’s an interesting fact to slip into your conversations.
Scientists say the number of sunspots is an indicator of how active the sun’s energy output is. Fewer sunspots mean lower solar energy output.
While the sun is in a quiet mood, I think we can expect cooler weather.
If you are holding your heating bills down at home, you must be doing the right things to keep the cold out and heat in.
Where I work, folks are doing a great job of keeping doors and windows closed to keep the heat inside. The results are showing up in lower natural gas use.
During November this year, we used about 20% less natural gas than last year in spite of the colder weather.
The improvement is the result of several things including:
The recent drop in energy prices helps, but reducing the use is a big improvement two ways. Lower energy use saves money and it helps reduce the stress on the environment.
Good for business and good for people.
You can save your money by saving energy at home too.
This is a guest blog by our friend Birney Summers from Energy Boomer. Birney is a practicing Energy Conservation Engineer who shares energy saving information on his blog.
Always remember to turn off the lights when leaving a room. Turning off just one 75-watt incandescent bulb that would otherwise be lit up for eight hours a day would save you about $20 per year.
(Or you could replace that lightbulb with a compact fluorescent light (CFL), leave it on 24 hours a day, and still save (a little) money.)