As you may/may not know, I’m stark raving mad. One of the things that catch my fancy is energy efficiency. I used to get a wierd kick out of logging the kWh on our meter each day and compare the readings with how we used our household devices.
Kicking this up a notch towards OCD, I recently purchased a Kill-a-watt. A Kill-a-watt is a small device that plugs in-line between your electric outlet and a device, up to something like 120VAC/15A (ie pretty much anything that can go into a standard outlet). It reads current draw down to an amazingly small level, and also performs quite a number of calculations, most interesting to me being the watt consumption of the device (I’d really like to be able to dial in my cost per kW and have it show how much it costs to run devices, but my spreadsheet works alright I guess, more on that later).
So, whereas before I had a rough guess as to why our electric bill has blossomed from $50 a month to $100 a month while the cost for electricity has stayed fairly stable around $0.10/kWh…now I can nail that shit down like a butterfly collector, closely and precisely examining each and every electric device at my leisure.
What I found was pretty close in line to what I calculated via the help of the new and improved PP&L website’s learning center:
| Appliance |
Energy per Year |
Avg Energy per Day |
Avg Watts per Hour |
Cost to run per Year |
Cost to run per Month |
Cost to run per Day |
Cost to run per Hour |
| |
|
|
|
|
|
|
|
| Computer |
2628.00 kWh |
7.200 kWh |
300.0 Watts |
$262.80 |
$21.60 |
$0.720 |
$0.030 |
| Hot Water Heater |
2227.00 kWh |
6.101 kWh |
254.2 Watts |
$222.70 |
$18.30 |
$0.610 |
$0.025 |
| Pond Pump |
1800.00 kWh |
4.932 kWh |
205.5 Watts |
$180.00 |
$14.79 |
$0.493 |
$0.021 |
| Aquariums |
1100.00 kWh |
3.014 kWh |
125.6 Watts |
$110.00 |
$9.04 |
$0.301 |
$0.013 |
| Fridge |
658.00 kWh |
1.803 kWh |
75.1 Watts |
$65.80 |
$5.41 |
$0.180 |
$0.008 |
| Ceiling Fan |
700.00 kWh |
1.918 kWh |
79.9 Watts |
$70.00 |
$5.75 |
$0.192 |
$0.008 |
| Air Filter |
700.00 kWh |
1.918 kWh |
79.9 Watts |
$70.00 |
$5.75 |
$0.192 |
$0.008 |
| Well Pump |
438.00 kWh |
1.200 kWh |
50.0 Watts |
$43.80 |
$3.60 |
$0.120 |
$0.005 |
| Stove top |
364.00 kWh |
0.997 kWh |
41.6 Watts |
$36.40 |
$2.99 |
$0.100 |
$0.004 |
| Oven |
227.24 kWh |
0.623 kWh |
25.9 Watts |
$22.72 |
$1.87 |
$0.062 |
$0.003 |
| TV |
219.00 kWh |
0.600 kWh |
25.0 Watts |
$21.90 |
$1.80 |
$0.060 |
$0.003 |
| Block Heater |
219.00 kWh |
0.600 kWh |
25.0 Watts |
$21.90 |
$1.80 |
$0.060 |
$0.003 |
| Lighting |
200.00 kWh |
0.548 kWh |
22.8 Watts |
$20.00 |
$1.64 |
$0.055 |
$0.002 |
| Air Conditioner |
180.00 kWh |
0.493 kWh |
20.5 Watts |
$18.00 |
$1.48 |
$0.049 |
$0.002 |
| Dishwasher |
145.60 kWh |
0.399 kWh |
16.6 Watts |
$14.56 |
$1.20 |
$0.040 |
$0.002 |
| Dryer |
119.60 kWh |
0.328 kWh |
13.7 Watts |
$11.96 |
$0.98 |
$0.033 |
$0.001 |
| Washer |
109.20 kWh |
0.299 kWh |
12.5 Watts |
$10.92 |
$0.90 |
$0.030 |
$0.001 |
| Furnace |
30.00 kWh |
0.082 kWh |
3.4 Watts |
$3.00 |
$0.25 |
$0.008 |
$0.000 |
| Coffee Maker |
5.46 kWh |
0.015 kWh |
0.6 Watts |
$0.55 |
$0.04 |
$0.001 |
$0.000 |
| Microwave |
2.63 kWh |
0.007 kWh |
0.3 Watts |
$0.26 |
$0.02 |
$0.001 |
$0.000 |
| |
|
|
|
|
|
|
|
| |
12072.73 kWh |
33.08 kWh |
1378.16 kWh |
$1,207.27 |
$99.23 |
$3.31 |
$0.14 |
| |
|
|
|
|
|
|
|
| |
|
|
|
|
(actual $102) |
|
|
That takes some pretty liberal guesses, and likely isn’t balanced correctly although the end result is nearly correct.
I’ve taken things like the pond pump and figured I run the 300W device 2/3 of the year, therefore the average draw per hour is 200W, etc etc. The pond pump is getting replaced with a 40 watt unit which moves half the water at 800GPH (and at $60 will pay for itself before the end of the summer in lower electric bills).
Big surprise was my fucking computer, sucking down over $20 of cash a month. The main problem is that I’m running Folding@Home on it, which bumps up the draw from a standby of around 75-100W up to nearly 300W. I’m running a version which takes advantage of my ATI x1950 Pro video card’s typically untapped calculation capability. Between the CPU and the video card, the system burns like a pile of lightbulbs. As much as I like the idea of helping FAH, I like the idea of cutting that down to $5 a month a lot better, so I’m going to put the comp into standby for the 18 hours of the day I’m not using it, where it is just keeping the memory powered up at about 10 watts (S3 standby mode).
I put a timer on the air filter to cut the run time down to an automatic 4 hours a day while we aren’t there. It is AMAZING how much electricity something uses when it runs 24/7. Same goes for our ceiling fans, I thought they used so little electricity that they were irrelevant and you could just leave them on all the time…80 watts x 24 hours x 365 days a year ends up being a pile of power…now everything is getting turned off when we leave the room…
Finally, the hot water heater has a timer on it which I installed a couple years ago. I can set a number of daily stages up on it, I think I’ll measure the instant draw (the watts per hour) with an ammeter and ‘decide’ how much I want to spend per month on hot water. I’m thinking around $10 a month at the moment, but we’ll see how I feel after my first cold shower. To help reduce the chance of a cold shower, I purchased an ultra low flow shower head, which we both have found is surprisingly adequate. Basically, with the timer and the instant draw, I can take the 1500 watts or whatever it draws, multiply that by the hours per day I’ll let it run (currently set from 5-6PM and 8-9PM), multiply that by 30 days per month, divide by 1000 (as there are 1000 watts in each kilowatt), and finally multiply that by the price per kilowatt of $0.10 per kWh.
Instead of doing this the long way, baby jesus came down from heaven and personally instructed me to create a spreadsheet, which you saw above. I’m still running the Kill A Watt on devices and making sure the guesses are in line with reality, so far things have been looking pretty good. For example, with the help of the PPL website, I guestimated our fridge draws 1.8 kWh per day, and lo and behold the Kill A Watt reported 1.80-something this morning after 24 hours of monitoring. I may run a second day just to get a better grasp on the average, but looks pretty darn close.
Below is an ‘in progress’ estimate of how I’d like the bill to look after some tweaking.
| Appliance |
Energy per Year |
Avg Energy per Day |
Avg Watts per Hour |
Cost to run per Year |
Cost to run per Month |
Cost to run per Day |
Cost to run per Hour |
| |
|
|
|
|
|
|
|
| Hot Water Heater |
1259.00 kWh |
3.449 kWh |
143.7 Watts |
$125.90 |
$10.35 |
$0.345 |
$0.014 |
| Computer |
876.00 kWh |
2.400 kWh |
100.0 Watts |
$87.60 |
$7.20 |
$0.240 |
$0.010 |
| Fridge |
658.00 kWh |
1.803 kWh |
75.1 Watts |
$65.80 |
$5.41 |
$0.180 |
$0.008 |
| Aquariums |
500.00 kWh |
1.370 kWh |
57.1 Watts |
$50.00 |
$4.11 |
$0.137 |
$0.006 |
| Well Pump |
438.00 kWh |
1.200 kWh |
50.0 Watts |
$43.80 |
$3.60 |
$0.120 |
$0.005 |
| Stove top |
364.00 kWh |
0.997 kWh |
41.6 Watts |
$36.40 |
$2.99 |
$0.100 |
$0.004 |
| Pond Pump |
300.00 kWh |
0.822 kWh |
34.2 Watts |
$30.00 |
$2.47 |
$0.082 |
$0.003 |
| Oven |
227.24 kWh |
0.623 kWh |
25.9 Watts |
$22.72 |
$1.87 |
$0.062 |
$0.003 |
| TV |
219.00 kWh |
0.600 kWh |
25.0 Watts |
$21.90 |
$1.80 |
$0.060 |
$0.003 |
| Block Heater |
219.00 kWh |
0.600 kWh |
25.0 Watts |
$21.90 |
$1.80 |
$0.060 |
$0.003 |
| Lighting |
200.00 kWh |
0.548 kWh |
22.8 Watts |
$20.00 |
$1.64 |
$0.055 |
$0.002 |
| Air Conditioner |
180.00 kWh |
0.493 kWh |
20.5 Watts |
$18.00 |
$1.48 |
$0.049 |
$0.002 |
| Ceiling Fan |
175.00 kWh |
0.479 kWh |
20.0 Watts |
$17.50 |
$1.44 |
$0.048 |
$0.002 |
| Air Filter |
175.00 kWh |
0.479 kWh |
20.0 Watts |
$17.50 |
$1.44 |
$0.048 |
$0.002 |
| Dishwasher |
145.60 kWh |
0.399 kWh |
16.6 Watts |
$14.56 |
$1.20 |
$0.040 |
$0.002 |
| Dryer |
119.60 kWh |
0.328 kWh |
13.7 Watts |
$11.96 |
$0.98 |
$0.033 |
$0.001 |
| Washer |
109.20 kWh |
0.299 kWh |
12.5 Watts |
$10.92 |
$0.90 |
$0.030 |
$0.001 |
| Furnace |
30.00 kWh |
0.082 kWh |
3.4 Watts |
$3.00 |
$0.25 |
$0.008 |
$0.000 |
| Coffee Maker |
5.46 kWh |
0.015 kWh |
0.6 Watts |
$0.55 |
$0.04 |
$0.001 |
$0.000 |
| Microwave |
2.63 kWh |
0.007 kWh |
0.3 Watts |
$0.26 |
$0.02 |
$0.001 |
$0.000 |
| |
|
|
|
|
|
|
|
| |
6202.73 kWh |
16.99 kWh |
708.07 kWh |
$620.27 |
$50.98 |
$1.70 |
$0.07 |
Here is the Power Usage Calculator if you’d like to play around yourself.
The end result of all of this was to see how much it would cost to install a photovoltaic / wind renewable system to help offset or eliminate our electric bill. By taking a couple minor and easy steps, I’m getting closer to a 2.5kWh photovoltaic system being a viable energy choice.
Like in all things, here is the obligatory statement where I promise to update and continue this topic at some later date. Hah! Go see Mozart and the Whale, I found it to be a very nice movie.