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How Much Electricity Do You Use?

posted by Jonathan Combs on Nov 7th, 2011 at 8:38am

This is a question that I could not have answered as recently as a week or two ago. I was actually surprised to find how little I knew and understood about our household electricity use, especially since I'm very interested in conservation. Also, I am very interested in alternative energy and hope to one day go completely off-grid with either solar or wind energy. I have recently started a project to create an inventory of all electiricity usage in the house and learn to predict what impact certain activities will have on the amount of electricity we use. We heat with propane, so this time of year is a perfect time for me to do this project, since I don't have to account for the electricity used for heating or cooling.

The first thing I did was go through our past electric bills and create a spreadsheet that summarizes them. I was able to download all of my previous bills from the local electric co-op's website. Armed with the data from every bill since we moved here (16 months, starting in July 2010) I began anaylzing the usage. A few things jumped at at me immediately.

First is that we were using more electricity last year than this year. In October 2010, for example, we used 626 Kwh (20.86 Kwh/day) while in October 2011 we use 377 (13 Kwh/day). That is a reduction in use of ~40%. I suspect that part of this is simply that since getting settled in we have been able to develop regular routines that are more conservation oriented than those first several months that we lived here. We were also still moving stuff in during the first several months, which means doors were being left open, etc. Another factor is that we often had a 3rd person staying with us on the weekends to help with projects, which is going to increse electricity usage some, especially when that person is not conservation minded. The last known factor is that our home is better insulated now than it was during our first months here. We are currently living in a mobile home, which is not the preferred structure for saving money on electricity. We were so busy with moving in and then doing other important projects at first that the home was open underneath for several months. As winter approached we finally enclosed it with insulated panels, which has surely helped energy use a great deal. Its possible that this had the greatest impact on our usage. Seeing the numbers now makes me wish we had made that more of a priority. There is one other potential factor that could have impacted our electricity usage, which I only now thought of. How was the weather last year compared to this year? After a bit of research I was able to find the information I wanted on the local University's Collge of Agriculture website. The average high temperature for last October was 71, compared to 67 for this October. It is possible that we could have used the air conditioner a bit more last year than this year, but I don't think the temperature difference is enough to explain the significantly lower electricity use, at least not by itself. I'm sure that the weather was a factor, though, along with the other items I've identified.

The second thing that stood out from looking through the data is that our electricity during 4 months is above our average monthly use. Those four months are June, July, August, and September. This is clearly due to using the air conditioner. Anything we can do to reduce the amount we use the air condioner will have a significant impact on our electricity use. In August, for example, we used 1451 Kwh, which is nearly 4 times as much as we used in October. Once Summer rolls around I will definitely be looking into ways of reducing that number.

The last thing that stood out isn't related to electricity usage directly, but the bill itself. Approximately 11% of the total we pay is for taxes and an environmental surcharge. These charges seem to be directly proportionate to our electricity use. In other words, the more we can conserve, the less we have to pay in taxes and fees each month. 

Now that I know how much electricity we use on a monthly basis I'm not satisifed. I want more of a real time picture of our usage. I have recently started doing a daily meter reading, which I am tracking along with my other information. I am using the Energy Consumption Analyzer Android App for convenience, but a notepad would work just as well. After 5 days I have seen daily usage range from 10 Kwh to 18 Kwh. Why did we use 18 Kwh of electricity in one day? We don't know. I'm working on figuring that out. If we reach our goal of living with an off-grid PV or Wind system, however, these types fluctuations could have a significant impact. I want to learn how to identify and predict these things now and begin the process of shifting my mindset regarding energy use before we begin sizing an alternative energy system.  For most people a fluctuation l ike that isn't a big deal. In fact, most people never even know that they have these types of fluctuations. Do you have daily fluctuations like this in your household energy usage? Do you know why?

About the Author

Jonathan Combs  

Comment by Jason on Nov 7th, 2011 at 9:06am 0 Likes

Any appliance that heats or cools and anything that pumps water is going to have a big impact on your electric bill. Electric Range, water heater, clothes dryer, well pump, pump in your basement sump, A/C, refrigerator/freezer, dehumidifier, space heater, even hair dryers and incandenscent light bulbs. Maybe the 18Kwh day was when you were doing laundry, or it was rainy and your basement sump pump was kicking on more than usual. Some of these modern conveniences are set up to run without you even being aware, but they still cost.

Comment by Jonathan Combs on Nov 7th, 2011 at 9:14am 0 Likes

I've stated figuring out the usage for each appliance. I thought I might do another blog on that once I have a little more work done. We have a few theories on what caused the increase, but I don't have all of the information yet.

Comment by Spun Gold Farm on Nov 7th, 2011 at 11:33am 0 Likes

For summer, you can plant some climbing vines on the west side to shade in the afternoon. Domestic morning glory will grow quickly and dies back with the first good frost, to allow winter sun in. Put a trellis a foot or so out and let it climb. Or, if you want food, use a purple Trionfolo climbing bean. Put the trellis out a litle more so you can get behind to pick.

Comment by Jonathan Combs on Nov 7th, 2011 at 11:45am 0 Likes

We've talked about using a vine for this purpose, but weren't sure what to use. Thanks for the suggestions. Sounds like the domestic morning glory might be something for us to look into.

Comment by Jennifer Kennedy on Nov 7th, 2011 at 12:56pm 0 Likes

We've sort of been keeping track of our consumption, but only by recording how much each bill is. The first winter we lived here, we were seeing bills that were $300 and $400 each month. This old place is heated with fuel oil, not propane. It smelled funny, was dirty, more expensive than we liked, and it didn't even seem to do a very good job heating the whole house...and there's just not that much to heat! Since our household power is hydroelectricity from the nearby dam, which we consider to be a couple of steps up from a coal-burning plant, we stopped using the oil heater and went with 2 small electric heaters. One is in the living room, and the other is in the bedroom, heating both halves of the house. Keeping in mind that our bathroom is poorly insulated and we use a space heater in there when we shower, we use the clothes dryer more during winter, and we have a quarantined cat in an outdoor room with his own small heater during cold months, our wintertime bills are still equal to or lower than our summertime bills, which have always been under $100. We've saved hundreds just by switching to a more efficient heat source. We're looking forward to one day having a wood stove and/or fireplace for that.

We've never bothered to track our Kwh usage, but you've inspired me to do it! I'll see if we can access prior bills online.

Great blog!

Comment by Jonathan Combs on Nov 7th, 2011 at 1:00pm 0 Likes

I forgot to mention it in the blog entry, but I think that not knowing how much electricity you are using has the same impact on conservation as not knowing how much money you're spending has on budgeting. If you don't understand where it is going its hard to know where your efforts are best spent.

Comment by ducknut74 on Nov 7th, 2011 at 6:23pm 0 Likes

You could look at your local hardware or home improvement store for you a current probe. If you clip it on at the breaker box for each circuit you could map out the vampire loads and the current draw for each appliance by turning them on one at a time.

Power(Watts) = voltage (120) x current (amps)
Watts x60 min=KW/hr.

Comment by Jonathan Combs on Nov 7th, 2011 at 7:03pm 0 Likes

That is a good idea ducknut74. I have been looking at devices to do whole house monitoring, but hadn't thought about doing manual checks at the circuit level. Thanks for the suggestion. Would a multimeter work for this? Or would I need to buy something different?

Comment by Coldspring Corner on Nov 7th, 2011 at 7:27pm 0 Likes

You will need a multi-meter with a clamp on type amp probe. The small multi-meters can not measure current very high. One other suggestion is to turn all the breakers off and then watch your electric meter while turning on a single breaker. Just make sure that the loads on that breaker cycle on while you are monitoring them such as an electric water heater, AC or a refrigerator.

Comment by Coldspring Corner on Nov 7th, 2011 at 7:40pm 0 Likes

Are there any success stories out there of folks using solar in the South with our hot summers? I just did an on-line solar calculator and a system to run my current home would cost $131,000 at 15kw. The home I will be building is half the size of my current place and even half that number is out of my reach. I've read about hybrid systems using a diesel generator.

Comment by Jackofalltrades1980 on Nov 8th, 2011 at 1:06am 0 Likes

That was the way I was looking at doing a solar system on a limited budget, I would size the solar system to run the small to intermediate loads (lights, TV, fans, occasional small microwave or hot plate for a few minutes) and use a diesel generator (which I made myself to run off of WVO) for running heavy loads like the washer, freezer, etc. Having the system interconnected also where the genny can charge the battery bank when it is running would give me a little more flexibility using the solar system to run heavy loads for short periods as well. We're in a mobile home and have a wood burner (mobile home approved) and with a hot fire it'll have the house at 85 degrees inside an hour. Of course in the south the bigger issue is AC.

Comment by Spun Gold Farm on Nov 8th, 2011 at 2:19am 0 Likes

That's where you start replacing with alternate appliances. Get a gas stove, etc. Start putting power strips to shut off the whole series when not in use. When you have to turn on the strip to use the item, you become aware of it. Also, I plan to super-insulate to minimize heating and cooling costs. Timers on bedroom lights, etc. limit power usage. Was the 15 KW YOUR usage or average usage for a house your size? I like the idea of starting now to ration your power usage to wean off of grid power appetite.

Comment by Jonathan Combs on Nov 8th, 2011 at 7:05am 0 Likes

Coldspring Corner - I wouldn't even attempt to install a PV system in our current home. It would probably take close to a 15K system to provide the amount of electricity we currently use in the summer months. When we build a new house, it will be built specifically to reduce cooling needs in the summer. We hope to drastically reduce our a/c needs. I would like to completely eliminate the use of a/c, but it may not be possible.

Was the $131,000 estimate for having someone install the system for you? Or just for the materials? Also, was this for a grid-tied system or for an off-grid? If off-grid, how many backup days was the battery bank designed for? I would think that you should be able to find panels for a 15k system for somewhere in the neighborhood of $30,000-$45,000. Of course you would have to add several other items. I would think you could build a battery bank to supply 3 days of backup for a 15k system for around $15,000. I can't imagine the remaining materials costing anywhere near enough to result in a total of $131,000.

Comment by Mrs. V on Nov 8th, 2011 at 8:44pm 0 Likes

We're trying to wean ourselves off the grid as well; our bills started to decline but have leveled off & we're frustrated. Our modular house came w/ a 3 ton air unit which we ran the whole first year (moved in during Nov.) & didn't get the wood stove in until the next fall. We did keep it off for the next cold & growing season until the heatwave came last summer. We set the thermostat to 80 the last week of June & it ran nearly constantly until the we felt it was more maneageable the second or 3rd week of Aug.
Switching to a clothesline saved an average of $40.00 a month. We'd like to put a sleeping porch up this year. We're charged $10.00 a month for a security light. Our refrigerator is old & has a poor seal so we are actively looking to get away from refrigeration. When our root cellar is finished we're looking to a spring house. After that, a smoke house.
Our biggest electical draws are from our well pump, water heater, fridge, & computer. They run most often. We'll probably get a window unit AC for next year. These houses are just not designed w/ any method other than central air.

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