Thursday, May 14, 2009

If I were you, would I go for the solar panel option on the i-house?

I dunno. I'm not you! It depends on so many factors. But I'll tell you what I think...

I’m writing this for some of you, who may be ruminating over the value or possible mistake, of buying solar panels for the i-house. This is just my opinion, how I’ve worked things out in my own mind.

Search for other opinions. I didn't pull all my figures out of the blue, but I did fabricate a set of figures for future energy costs in the next thirty years. No one knows what these will be. I tried to take a middle road between two extremes.

Try to find blogs, video and articles from people using the technology. There’s a book, SOLAR POWER YOUR HOME, FOR DUMMIES, that you can find in a library. I had physics course in solar energy in college, but it has been so long, I had to figure what a kWh is, all over again. It is simple when you think of it in terms of solar panels. I'll try to explain it later in this post, if it didn't sink in from watching the videos in my last post.

Purchasing solar panels is not a way to save lots of money. The money spent on solar panels is more likely a break-even situation, unless you use them more than 20 years. Then, some real savings could kick in.

There is another kind of savings though, especially if you are in an area where the power is generated from coal. The burning of coal is polluting. Having solar panels will allow you to burn half as much coal (coal burnt at the local plant), and pollute half as much.

Find your last month’s electricity bill. Where it gives your meter reading for the month, pretend it says 1000 kWh (kilowatt hours) which at .10/kWh would give a bill of about $100 (ignoring the taxes and fees they add on.) So, that is a hundred dollars per month, so $1200 for a year.

This could be an average bill for a family that uses an electric clothes dryer, or electric hot water, or an air conditioner, or an electric space heater during cooler months, or has an electric well pump. (If you are on city or town water, you are not using a well pump.) $100/month electric bills would probably be low, if you live in Phoenix or Florida and use air conditioning, or if you have an all-electric house.

For the average of 1000 kWh/month use, ($100 monthly bill),that translates into burning 800 pounds of coal. Isn’t that incredible? So, at the coal plant they are burning 800 pounds of coal just to power a house for a month.

So, opting for the 2K solar panel, you’d avoid putting the pollutants from 200 pounds of coal burning into the atmosphere for a single month, and 400 pounds, if you opt for two 2K panels. (4k total)

Let’s say your electric bills are only $50/month. With 4K of panels, you would still save burning of 400 lb. of coal (at the power plant) and also save the same amount of money.

Let’s get back to basics.

A 2K panel is a 2000 watt panel. Under fairly sunny conditions, a 2K panel generates an average of 8kWh/day. That is, it generates 1000 watts for 8 hours. One kWh would be 1000 watts for one hour. kWh stand for "kilowatt hour."

You are thinking, how come it generates only 1000 watts, if it is a 2000 watt panel? That is simple. The 1000 watts for 8 hours, is just an average. When the sun is coming up, it may be generating only 200 watts for one hour, and the next hour 300 watts, and during the few hours of the day when the sun is shining brightly on the panel, it could generate near the full 2000 watts for each hour. Cloudy days and rainy days are factored into this average.

Using power during the day is when it is most expensive. That is when your biggest savings can come from using solar panels. The power company charges more for power during the day. You can see this on your bill. There are usually three different rates per kWh, depending on when you are using the power.

And what power you don’t use during the day, is credited to you, back in the grid at the higher daytime rate. I’m speaking about a grid-tie system only, which will be the thing most people get. People off the power grid, of course, opt for an off-grid system with batteries. They are not hooked to the power company at all.

Thanks for the comment below which answers my question about the inverter. Panels convert the sun's energy to DC and need an inverter to convert it to AC. Ready Solar, the panels used in the i-house, if you order them as an option, uses a special built-in inverter with each panel. So the inverter is included in the price.

The Clayton i-house official site blog -- just that portion of their site -- is down for a while. It got bombarded with hundreds of questions on May 7, the day of the AP article. If you didn't get your question answered, they'll probably get to it, or you can call them.

For the sake of simplicity, I am going to use a .10/kWh rate of electricity across the board. This is probably two cents than most of you pay. In places like California, it could be two cents less.

Picture using a 1000 watt microwave oven for one hour. That would cost 10 cents at the rate of .10/kWh.

Here is the scenario I’ve set up. You buy your i-house in January of 2010. You opt for the full 4K of solar panels for $26,800.

Here is the next 30 years of your energy bills, predicated on you using 1000 kWh/month, AND, electricity going up one cent/kWh each year of the next decade. Some might think this is a modest estimate of increase. Others think that electricity, in twenty years could jump to ten times its present rate, to $1/kWh. I am trying to do a reasonable estimate, somewhere in between.

Savings from Solar Panels on Yearly Electric Bills for Three Decades beginning in 2010.

2010 @.10/kWh $600 Saved $600
(without solar, your bill would have been $1200)
2011 @.11/kWh $660 Saved $660
2012 @.12/kWh $720 Saved $720
2013 @.13/kWh $780 Saved $780
2014 @.14/kWh $840 Saved $840
2015 @.15/kWh $900 Etc.
2016 @.16/kWh $960
2017 @.17/kWh $1020
2018 @.18/kWh $1080
2019 @.19/kWh $1140
First decade savings = $8700 (half your bill)
(Without the panels your bill would have been $17,400)

With coal shortages and inflation, energy prices go up in 2020, with a 02.kWh rise every year, instead of just up .01 every year.

2020 @.21/kWh $1260 Saved $1260
2021 @.23/kWh $1380 Etc.
2022 @.25/kWh $1500
2023 @.27/kWh $1620
2024 @.29/kWh $1740
2025 @.31/kWh $1860
2026 @.33/kWh $1980
2027 @.35/kWh $2100
2028 @.37/kWh $2220
2029 @.39/kWh $2340
$18,000 (this decade)
+ $8700 (decade 2010 to 1019) = $26,700 savings
So after 20 years, the $26,800 you paid for 4K of panels is paid for. (A 2K panel would also be paid for after 20 years.)

For the third decade, you get all the electricity from your panels for free.

2030 @.42/kWh $2520
2031 @.45/kWh $2700
2032 @.48/kWh $2880
2033 @.51/kWh $3060
2034 @.54/kWh $3240
2035 @.57/kWh $3420
2036 @.60/kWh $3600
2037 @.63/kWh $3780
2038 @.66/kWh $3960
2039 @.69/kWh $4140

In the third decade you have saved $33,000, free and clear, your solar panels. Of course, $33,000 won’t be worth all it was back in 2010.

But, in the last three decades, you will have avoided burning over 140,000 pounds of coal through the use of your solar panels. Because of solar use, you will have not sent the emissions from the burning of 70 tons of coal into the atmosphere, or created the equivalent in nuclear waste, if you get your power from a nuclear facility.

Also, consider that in ten years, you could very well be driving an electric car, and adding more solar panels, saving substantially over gas prices, AND polluting less.

Do panels have a downside, other than just the initial investment, or a risk that a source of cheap clean power may be discovered in the future, such as nuclear fission-fusion reactors?

They do have a downside. In order to function optimally, they have to be cleaned every once in a while (hose off the dust), and if you are in an area with some snow, the snow has to be swept off them. Plus, instead of having a nice clean roof surface, solar panels are mounted there. They may get leaves or other debris stuck around them, or trap snow and ice.

Something might happen to a panel. A tree might fall on it, or it might get vandalized.

Solar panels degrade, but lose only one quarter of one percent of efficiency each year. Also something I learned from the video. When they heat up too much, they lose 10% efficiency. So, they work better in cool sunny areas, than they do in hot sunny areas. But that shouldn’t be as much of a consideration, compared to how many sunny days you have per year. In New Mexico, it is as sunny as most of California.

Opting for a smaller or more energy efficient house, in itself, is choosing to reduce your impact on the environment.

Here are the two basic reason to buy the solar panels:

1. You would like to use some clean power.
2. You have the money to pay for the solar panels.

If you are paying a mortgage on the i-house, well, opting for the solar panels probably won’t work out, as far as saving money goes. However, they could be seen as a possible wise investment, if you had to sell the house five or ten years down the road. I wouldn’t buy them just for investment purposes though. In ten years, they may come out with a generation of cheaper and more efficient (convert more of the sun’s energy to power) solar panels.

People get a deep satisfaction from using solar panels. The satisfaction is in not polluting, in using clean energy.

I don’t have solar panels. I wish I had money to buy them. I wish I had bought them when I did have money, instead of investing it in stocks that failed. There is so much sun here. It would be great to use it to power things in my little house.

Panels contain an amount of embodied pollution, in their manufacture. In other words, it is polluting to dig for the raw materials used, and use energy to make them in a factory. However, that is made up for very quickly in their use.

A wood stove can economical for heating, especially if you live on wooded property or in a wooded area. However, wood is very polluting. At least wood stoves have become more efficient in recent years, and are not as polluting as they used to be. Wood stoves with a catalytic unit don’t pollute, but the catalytic part has to be changed every few years. It is expensive. It is a good option, in terms of the environment, if you can afford it, and have plentiful wood to burn without having to cut trees down.

Are there other alternative energy alternatives? Sure. There’s wind, if you live in a windy area. And many power companies offer an option to purchase solar power through them. Your money goes toward building their giant windmills or solar facilities. It is a few pennies more per kWh.

Here’s my favorite from a company right here in Santa Fe. It is a hybrid solar/windmill. Click on the link, and watch the video.

Bluenergy Solarwind Turbine

It is not commercially available yet. So, when the sun isn’t out, it works as a windmill, and during the day when the sun is shining it can work as both, or it spins just from the solar cells. No wind or no sun, it would need battery backup or grid. They expect it to retail at around $20,000 I guess.

It might be one of those things that makes someone want to wait for a few years, to see if it might not be THE NEXT BIG THING.


Passive solar, can be important in cutting heating bills. You can save a lot in heating bills during the winter by siting the i-house, so the side with all the windows is facing south. With the big window/door units on each end, it would also allow some latitude in that.

Some people might feel the I-house doesn’t have enough windows. As good as Andersen windows are, in terms of quality and energy efficiency, they are nothing like having wall, especially on the north side of the house. So, I think the i-house people did the windows just about right. Plus, they have a few optional windows you can add, if you want.

I don’t like houses with too many windows. The light can be blinding inside. It is impossible to get away from light reflection on a computer screen or TV, if there are lots of windows on three or more sides of a room. Then again, the sun is very intense where I live. During a day of temperature in the 20's, I can turn off the heat in the middle of the winter, and my house warms up from the sun coming in three windows on the south side. I have no windows on the north side. Zero. Not even little ones, like the i-house.

Lastly, back to solar panels. A factor you may consider is that presently there aren't any government rebates to help pay for such things. In Australia, they had a program for a while, offering large rebates.

You can always add solar panels to your i-house later, since Obama might institute some kind of rebate or tax incentive on their purchase, within the next few years.


  1. Nice article about the solar panels's advantage.

  2. The panels are made by a company call Ready Solar. Each panel has a mini inverter built into it.

  3. Thanks for that info on the inverter being included in the solar panel. I'd read their rather sparse site, and missed the one line which mentions that.

  4. "not enough windows"? What? I was thinking there were TOO MANY windows! You'd have trouble finding places to hang a picture in that glassbox living room.

    You'll spend a bit of money buying blinds or drapes for it. I'm imaging tons of glare on the TV screen, sun-damaged furniture, and difficulty reading a book in that glass terrarium.


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