Watt Watcher



I changed my idea for my final project and decided to create a Watt Watcher.

A Watt Watcher is a device that you can plug into any appliance to monitor and gauge your usage of electricity. Every month, I get an electric bill and I see a number like 376, or 404, or 382. What does this mean? How did I get there? Well, some of it I know. They are KiloWatt Hours. Those are the number of 'thousand watts' that have been consumed in hours. Okay, so that sounds confusing. Here is an example:
If I have a light bulb, I can read on the light bulb that it is a 100 watt bulb. In general, devices don't neccessarily use as many watts, amps, etc as listed, but that is basically where they max out. Okay, back to the light bulb. We've got a 100 watt bulb. If I run that bulb for one hour, then I've consumed 100 watts. If, however, I have 10 bulbs on for that hour, then I've consumed 1000 watts in that hour, or 1 KWH. So what? That 1 KWH costs $0.15, for example. Again, so what? You can pick up $0.15 walking down the street.

Let's look at the bigger picture. I agree that it is too much trouble for $0.15, but that's not what I learned in my marketing class. In the marketing class, we learned that they sell light bulbs, which are compact florecent rather than incadencent, which use 10 - 25 watts, rather than the 'normal' bulbs which use 60 - 175 watts. In this class, we said that the cost of the CF bulb was ~$20 compared to a regular bulb which can be purchased easily for $0.50 (or less). So the question was 'Is it worth spending $20 for the CF bulb?' Of course not. Its $20!!! Well, as it turns out, that's not quite true (except for the $20 part). Here's why:

Let's take that 100 watt bulb. Let's use it every nite for, on average, 3 hours or so. 3 hours * 100 watts * 365 days = 109500 watts or 109.5 KWH (okay, i needed a calculator for that one also. At $0.15/KWH that single bulb costs us $16.43 for the year. ($16 for one bulb!) That CF bulb, on the other hand works out something like this: 3 hours * 15 watts * 365 days = 16.425 KWH. That's $2.46/year. A savings of $13.97! Not bad, huh? Still, $20 for the bulb. Well, even if you got the incandcent bulb for FREE, you've 'broken even' in about 1.5 years. As it turns out, though you can buy the bulbs easily for $5 - $7 (or less). So, now you've broken even in about 6 months or so! Keep in mind, that it only ONE bulb. How many light bulbs do YOU have in your apt/house? Did I mention that's only 3 hours/nite?

So, that got me thinking. First of all, I went out and replaced all of the bulbs in my apartment (and many of them in my mom's house too). But it started raising more questions in my mind. If my light bulbs are using so much electricity and it was 'so easy' to cut their consumption by 5/6ths, then what about the rest of the apartment. I mean, ten cents here and ten cents there, but in the long run it REALLY adds up (see example above). My desktop computer's power supply is 300 watts. Its on all of the time. Plus I have another machine that is my web server (no geek comments, please). It is also on 24/7. Plus my laptop and all of the other appliances and things that are constantly in some state of 'on' seemingly all of the time. How much are THEY costing me? Does it make sense to replace them with something else? Is a cheap laptop 'cheaper' than a desktop, if it uses less electricity?

And hence... a project.


Example Light Bulb Datasheet     Energy Star Air Conditioner Example