12May

How much does solar cost?

Wednesday | Filed in: Grid-tie solar

Solar cost? How much is solar power going to cost to run my home or business? This is usually the first question asked by someone who is exploring the idea of using solar power to run their home or business. Seems like a simple enough question. However, the answer is not so simple to get to without a little up-front information.Short of throwing some broad, vague meaningless numbers out there, if the person asking the question can provide the last 12 months PG&E or SMUD electrical bills, we can glean much of the information to provide a meaningful answer. O ya, one more thing, it is actually helpful to see the last bill rather than just the summary numbers so we can look at the rate your power company has you on. It makes a big difference when considering the payback.

You may say to yourself that this seems pretty basic, but I just got off the phone with someone that wanted a price on solar, and advised he was using 14,000 kWh per month on 3 buildings. The average US home uses about 11040 kWh per year, an average of 920 kilowatt-hours (kWh) per month. So I said OK, got a little excited then asked the next question. What is the address of the buildings? The caller was unwilling to give me the address only saying the buildings were on the same property. When I pressed him on the importance of knowing the addresses of the buildings for orientation to the sun etc., he got frustrated with me, “well thanks anyway” and hung up. I suspect he was concerned of some uninvited intrusion into his privacy. Probably a good thing for both of us since it is my experience that to properly size a solar system for a home or business it take a cooperative team effort between the owner and the solar company. If that is lacking in the first 5 min of the conversation, it does not make much sense to go farther.

There are four questions you need to consider carefully and answer in order to create a good system design. How much energy is available? How much energy do you use? How efficiently are you using the available energy? and How much will it cost? The first question addresses the availability of potential solar energy at your site. To assess the amount of solar energy available to you, you must know your address and zip code then we can find the number of peak sunlight hours at your site and to look at the local utility available rebates. We can use Google Earth to take a quick look at your roof orientation and layout to get an idea if the site is a good selection for solar. Even if there are problems with a roof application, ground mount or awning mount can sometimes work.The second question you will need to address is the amount of energy that you use. In order to accurately size a system you need a fairly accurate idea of your average daily power consumption. This information can best be obtained by pulling up your last 12 months power bills and then faxing them or running a summary on line and e-mailing the information.  While assessing your power needs, you can answer the third main question: How efficiently do you use power? This is a good time to note what appliances and lights in the house use a large amount of power, and figure out if you want to replace them with more efficient products. In many areas rebates are available to help off set the cost of older appliances. Some items which provide considerable savings in energy are switching from incandescent lights to compact fluorescent lights. If you are building (or even remodeling) a house, you may want to consider using passive solar design. By using some fairly simple design principles, you can create a house that stays warm in the winter and cool in the summer, helping to decrease the amount of energy needed to heat and cool your house.

All of these considerations lead to the last (and some say most important) question: how much will it cost? The more accurately you assess your energy needs, and the more energy efficient your appliances and home are, the more cost efficient your design will be. At some point a site evaluation is needed to completely answer all the questions and provide an accurate quote. Look at the video and it will give you a good idea what happens in a site assessment. Usually takes about an hour.

Some companies will quote you on the spot and then pressure you to sign us. I have been in building materials sales for many years and it is my feeling that it is better for both parties if the customer takes their time and is well informed about expectations. Energy independence is a great feeling but we have a responsibility to the industry to make sure you are getting the best return on investment you can get. Selling the largest system your roof can handle is rarely the best idea.

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