Jun 17 2008
Solar Power for an Apartment?
I’m moving to a new apartment in mid-July. One of the things that I was going to do at my current residence is to install solar panels. Except that the lease has a clause about not having “large and obstructive” objects on our patios. I asked the manager if solar panels qualify as large and/or obstructive and was told in no uncertain terms that I was not allowed to have them on the patio. Of course, the lease also forbids charcoal grills and I’ve seen at least 5 on other peoples patios. A couple solar panels might attract more attention than a grill though.
I fully expect that I will not be able to install solar panels at my new residence, but decided to spend a little time looking anyway. I don’t want them because they’re “green” or other such nonsense, I want to save money. The lease is only for 12 months, and I am not under any delusions that I will recoup my investment in that short of time. But I will then have the capital, and will not need further investment.
Energy Consumption
The first problem is that I don’t even know how much energy I use in a day/month/year. I can’t even look at the bill from the energy company because my current rent includes the cost of electricity up to a certain amount. I’ve never gone over that amount, so I don’t know what it is. Setting aside the silliness of including electricity in the rent, the only way to determine energy usage is through a meter - which just happens to be in my apartment. So I wrote down it’s value when I walked home for lunch. At lunch tomorrow I can see how many kWh I’ve used in 24 hours. This will give me a rough estimate for how much energy I use on an average day.
The next step was finding all the things in my apartment that use energy. Since I live where it is very hot in the summer, it is almost a necessity to use air conditioning. I keep it on for 24 hours a day, set at 85F when I am not in the apartment and 75-78 when I am. I use A/C from around the beginning of June through the end of August. During the winter, I use very little heating. This last winter I turned on the heat only 2 nights.
Onto everything that I have plugged in. The refrigerator runs 24/7. I don’t seen any way around that since I have food that need to be kept cold. The oven/stove is plugged in, and get used once in a while. The computer and ceiling fan are on usually whenever I’m there at night and am awake; usually around 4-6 hours. The microwave is hardly ever used, but contains a clock. The phone likewise contains a display, but is hardly used. And there is the requisite clock radio so I can wake my sorry butt up in the morning.
I have several lights in the apartment that are hardly on. I have a florescent reading lamp which probably gets the most usage. There are 4 incandescent light bulbs on the ceiling fan, but I only use 1 or 2 at a time. There is 1 tube florescent light bulb in the kitchen, and 4 small wattage bathroom bulbs (3 incandescent, 1 CFL).
Cheap Solar Installations
That was mostly for myself, so sorry if you read all the way through it. But searching on the Internets found two do-it-yourself guides to setting up small solar panel arrays. The first is on bastish.net. He used two 70W panels with one battery, add in an inverter and controller and the cost comes to $1,764.
The second guide was at Instructables.com. She used three much smaller solar panels totaling 60W and three batteries. He stated that on one battery he could power a lamp and a light bulb for over 5 hours. Obviously the more batteries, the more power. So in terms of power, 3 batteries are better than 1, and 5 are better than 3. But that brings me back to the fact that I don’t know how much power I need.
How Many Watts? How Much?
The price per Watt for the two designs is about the same: 140W for $1,764 ($12.6/Watt) and 60W for $650 ($10.8/Watt). According to Mr. Electricity, the Wattage of his refrigerator is 300W. That’s only for when the compressor is on. And I have no idea how often that is. When the compressor is off, it only draws about 5W.
Let’s assume that the compressor is on for 4 hours in a day. I think this is probably high, but as I said, I don’t know, and I’m looking for a high estimate of the cost. The cost of electricity was 8 cents/kWh in Arizona in 2006. Let’s assume that the cost of electricity is now 11 cents/kWh. For the 4 hours per day that the compressor is running added for the entire year, the refrigerator costs $49. That means that it’s on “standby” 20hr/day. Again assuming 11 cents/kWh, that comes to around $5 per year. This means that it costs only about $54 per year to cool a refrigerator.
Assuming that the cheaper of the solar panel options above produced 60W of power 24/7, that would only save $58 per year. Which means it would take over 11 years to pay off the initial investment. And the actual time will be more than double that since they would only produce power when there is sunlight hitting them. So unfortunately, it doesn’t look like a small cheap solar installation is worth the investment at this time. It’d still be pretty cool to have though.
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14 Responses to “Solar Power for an Apartment?”
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Finally … welcome back home, Earthling.
I’m not sure of the meaning of your comment, but thanks for posting.
I bought a KillAWatt to figure out the average power usage of my refrigerator. My old, cheap KillAWatt displays the energy used (in kilowatt hours) and the time its been on (measured in hours), so it’s simple to figure out average power usage. My refrigerator is almost 30 years old and over the 2 weeks I used the KillAWatt this winter, I found that it uses an average of 200 watts. Since I live in a very warm climate (New Mexico), it gets very warm in the summer and decreases its efficiency, probably making the average power usage more like 250 watts or 300 watts.
New refrigerators, however, are much, much more efficient; full sized energy-star fridges can use an average of around 65 watts, and though they cost slightly more than less efficient fridges to purchase, this efficiency might save you money in the long run.
Anyway, if you don’t care to read all of that, I just suggest you get a KillAWatt or something similar (or maybe just turn everything except your fridge off for a few days you won’t be there or something and measure the power usage then). Or if your fridge is fairly new, you might be able to look up its estimated power usage online (check out “recyclemyoldfridge.com”)
The problem is you are considering a battery system (off-grid) this significantly adds to the cost per watt because of the batteries and other components used to store the power. With a battery based system you need to maintain the batteries once a year and replace them every 5-10 years depending on the battery.
You may want to consider a 250 watt plug n play grid tied system we have on our website which allows you to grid tie your solar panels by plugging in to an AC outlet in your apartment! Its the first kit in the US market that allows you to take advantage of a grid-tied system with the ease of installation.
check it out:
Tell me what you think!
That looks good. But I still don’t think it makes economic sense to buy one. By my calculations, it would take me about 16 years to pay back the initial investment. This is better than the two options above, but still a little long. Thanks for the comment and link though.
Atmoz, you did not say if the new apartment rolls the ebills into the rent or not. [Reply: They don't.] If they do, anything you do to reduce your energy bill below the average for all units you are just putting money in the complex owners pockets. However, if you are actually going to receive an electricity bill then you can do a lot. Try to get an inside apartment, that is an apartment with neighbors above and below or on the ground floor not on a corner. Check the weather strip at the door to see if it is good and maybe get some thermal covers for the windows. They are probably not double pane energy efficient and those guys radiate a lot. The KillAWatt plug in meter is a good idea for checking the appliances and also for checking the power bill. If you have a specific meter for your apartment you might find it and then close your main breaker and see if the meter wheel stops spinning. If it doesn’t stop then the complex has some splainin to do.
http://www.powermeterstore.com/index.php?cPath=112&products_id=4578&s=GA&gclid=CNG2wtWg_pMCFQi1IgodBCmFWA
IF you are using batteries, you need to use special-purpose ones designed for the intended purpose. Unfortunately they are expensive. So you need to check before proceeding.
[Deleted.]
There have been recent articles on solar cells being “printed” on flexible substrate. This will allow them to be applied to windows, walls… I don’t think solar will be useful to apartment dwellers until this technology hits and we can “decorate” with it. May even be able to use it for flooring on a patio with the right materials!!
People with pools can use it for a pool cover to offset the costs! Electric vehicles can be covered with it for extended range and charging when parked outside…
The small areas available to us for conventional panels will expand dramatically with the newer tech!! It also is projected to be much less expensive.
http://www.popularmechanics.com/science/earth/4253464.html
As an Ohioan, the local utility has a calculator that let’s us estimate our energy usage. I don’t know if your utility has one, but you can play with this one:
https://www.aepohio.com/CustomerService/HelpfulInformation/SavingEnergy/Default.aspx
You don’t mention hot water, or an electric shower. Either would be likely to be a major contributor to your energy consumption.
As to how long it takes to recover your investment - you are assuming that the cost of your electricity will remain constant. I suspect that it won’t.
Here in the UK the media has been full of dire predictions of a 40% increase in energy costs this coming winter, due to the steep increase in the wholesale price of gas.
I believe that most of the electricity in the US is from coal-fired stations, and the price of coal has more or less doubled in the last 12 months.
Having said that, procrastination is probably not a bad idea. As KuhnKat says, costs are likely to come down. When I did a similar exercise on CFL bulbs about 3 years ago, they didn’t make economic sense at the time - but now the price has since dropped to around 25% of what they cost then, while the price I pay for a kW went up by 19% last year alone.
You are just like Joe Romm: You can’t take Harold Heat!
Why do you worry about all this global warming gobblygook and climate change claptrap? Don’t answer!
Old Weird Harold says this is what you should be worring about:
“How much money do you saved for retirement? And when you retire, are you going to have at least several million in assets?
Go to GISS, get the data for the Parowan Power Plant. Then do an analysis to determine the trend. Come back and tell to us what you have found. Don’t use the datum for 1934.
Note that the only major climate forcing at this remote and arid site is CO2. How much is it?
[Reply: Some people think about other things than money. You're obviously not one of them. Looking at the temperature data from one station is not going to be representative of the entire globe. Please see the newly adopted comment policy, paying particular attention to the 2nd and 3rd items. Thanks.]
Look into a solar hot water heating system instead. Simpler and less expensive.
[Deleted. Off topic. See comment policy.]