I am currently working on my senior design project in electrical engineering.
The idea is to put an energy meter on every device that draws power (including lights) in your home, wirelessly send that information to a central data storage device, and access that data with a PC. We will provide software that will calculate average power, total energy use, and instantaneous power (in graphical form) broken down by device. Finally we’ll translate that information into a dollar value. The goal is to educate frugal consumers and facilitate economical energy usage decisions.
Anyway, now that I’ve bored you by plugging my “product”, I’d like to ask the question: How many devices are we talking about here? I’ve tried googling for a GQ answer on average number of electrical devices per household to no avail, so I thought I’d make it a poll. How many appliances are plugged into your house?
I’ve been designing for 100, but that is a number I just pulled out of my ass. My wife and I just estimated about 40 in our household, but our house is pretty small.
So please, take a look around, make a few simplifying assumptions, and give me your best estimate.
I know you didn’t ask for an analysis, but I see a potential problem here, unless your metering devices is very small. About 75% of the devices in my house (approximately 50-60 devices, depending) are plugged into outlet strips with the typical spacing of about 1.5" on center. You going to monitor the outlet strip as one device, or did you intend to monitor each device on the strip independently?
eh. Your right. They are not of course. Water heater is.
Does the OP want to include major appliances? I would think that any information would have to include what device is using electricity, and where it is.
Washer
Dryer
Fridge
Stove
Toaster oven
Microwave
DR light
Kitchen light
Range hood
Under-cabinet lights
Under-cabinet radio
Coffee maker
Cordless phone base
Cell phone charger
KA Mixer
Ok, I’ve counted 15 in my kitchen and dining area, my washer and dryer live in a closet off the dining room. So does the hot water tank, but I don’t think that’s plugged in, just gas.
If we’re counting power strips at the computers and television stuff as each device plugged into the strip and not just one strip into the wall, I’m thinking about 75 or 80. I have multiple can lights in a couple of rooms, do those count as one fixture or individuals? What about hard-wired smoke detectors, they’re daisy chained together so how do we count those?
Two people, smallish house:
10 overhead lights, but only 3 or 4 are really used
furnace, bathroom fan, and several smoke detectors are hardwired. I’m not sure if the water heater uses electricity.
about 25 things always plugged in (or about 20 if you count a power strip and everything in it as one thing)
about 20 things occasionally plugged in when being used (not all at once!)
I definitely want to include major appliances. We probably won’t get this far in the prototype demonstration version, but it is only a matter of changing the physical shape of the meter to get it to measure power flow through light sockets, 220V receptacles, or even hardwired appliances. Right now we’re focusing on 120V receptacles only.
However, I did plan on using counting power strips as one device. Actually, it is the user’s choice, but like Q.E.D. said, the meters won’t fit on closely spaced power strip outlets. I’m envisioning monitoring systems like “Computer” or “Entertainment system” as a whole, peripherals and all, for exactly that reason. But ultimately it is the user’s choice. If you want to monitor the power usage of your printer separately from your computer, you’ll just have to find an outlet that will fit the meter. We’re trying to make the meters as small and cheap as possible, but it will still probably be worthwhile to minimize the number of them to some extent.
So instead of “How many devices are plugged into your house” maybe I should have asked “How many electrical subsystems do you have in your house, with “subsystem” defined as something you’d like individual power usage information for?”
29 in a one bedroom apartment, fwiw. That’s anything using power, not battery operated. Almost forgot my dispose-all, and the light in my porch closet. I have maybe 20-30 free outlets, without using extensions.
Stove, fridge, microwave, couple of floor lamps, reading lamp (currently unplugged), couple of floor fans during the summer, iron (intermittently plugged in), TV/cable box, VCR, DVD player attached to TV, portable DVD player with its own screen, computer, printer, hard drive, broadband box (all of the previous four plugged into a surge protector which is plugged into the wall), and alarm clock. 18 by my count.
4500sf McMansion, two people, definitely not gadget freaks but with a home office:
22 computer or electronic gizmos, counting from TVs all the way down to always-plugged-in cellphone chargers. Another dozen-ish rarely used ones stored in the basement.
38 pluggable lamps or small appliances (toaster, alarm clock, etc) plugged in. Another dozen or so appliances and hand-held power tools unplugged unless in use.
17 big items either hardwired or pluggable. e.g. washer, dryer, HVAC, sump pump, oven, etc.
I have neighbors who could easily do 3x-5x that number with twice the electronics per person and 3+ kids. Not to mention a garage and/or basement workshop full of power tools. And a 15-component home theater for him. And a wife who abhors the idea of an empty outlet & will stick a lamp everywhere & anywhere.
I have about 120 light bulbs in my house – I know because I just replaced most of them with CF. However, several are linked together and are controlled by a single switch. Add in appliances and electronics and I say about 170 “devices” total if you count each light bulb individually.
That seems very high to me, unless we’re counting Christmas tree lights. Does this figure include only main interior/exterior lighting or are we also counting night lights and appliance bulbs?
ETA: This Energy Star fact sheet says 45 bulbs. That sounds more reasonable to me.
Not to hijack this thread even further, but I’ll give an example. Our master bedroom has an overhead light fixture with two bulbs, a reading lamp above the bed with two, a desk lamp with one, and two bulbs in fixtures in the closets. That’s seven bulbs just in this one room.
OK, I just counted and we have 33 outlets in use (and 31 light bulbs if anyone cares). Sounds like it’ll be an interesting project; I’ve been in many houses where I’ve been dismayed to see how much they’ve overloaded their circuits with extension cords and power strips. Frayed and overloaded extension cords especially are a recipe for disaster. I know energy conservation is what drives a project like this but the safety factor is huge as well.
Simple way would be to just count your receptacles in use, add about 10 more little sending units for added drills and vacuum cleaners etc. that are occasional use and run with it. Anything over what they detect will be hard wired circuits so you just need to monitor the meter at some regular interval.
I have a little KillAWhat <sp> meter that I can plug into a receptacle and it gives volts, amp, watts, and total watts over time. Learned a few things that I did not know as far as power consumption was concerned. (About $14-30, I forget.)
If I was working individual items, I would be even more likely to be careful about turning off and unplugging things. Really need to change nothing for a study like that to do you any good. Would be easier for me to do as I normally do it it was just at the receptacle so I could forget it. YMMV